ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Greetings All
As I get used to the prodigious performance envelope of my new Lab 9's, I find myself coming to grips with some rather clever technologies, the function of which, in the case of ABL or Adaptive Bass Linearisation, I am unable to find re an in-depth answer as to how it is technically implemented.
B&O describe it thus:
"ABL is a Bang & Olufsen patented solution basically to get more bass in small spaces. It is a solution where we make use of the surplus capacity in the built-in amplifiers and driver units at normal listening levels, for a bass extension. With this, we get more bass than the loudspeaker would otherwise be able to produce. However, this solution entails a risk that the driver unit might not be able to handle the extra boosts at higher volume levels. To solve this, we have introduced an electric circuit to monitor the sound level, so when the music peaks in the lower frequency areas and maybe come close to distorting the sound quality or damaging the driver unit, the bass signal is reduced accordingly
Bang & Olufsen developed Adaptive Bass Linearisation for high-end speakers like BeoLab 9, building a reputation for big and authoritative sound from relatively small speaker cabinets."
From this description, my guess is that technically, where the bass drivers starts to roll of re frequency response, the power and amplitude response is boosted, so as to extend the overall frequency response of the speaker; conversely, at higher volume levels, the boost is reduced so as not to overload the driver.
I am curious though, and would like to find out as to whether this feature protects the bass driver against mechanical overload/damage from other sources of bass boost, such as tone controls (bass) at maximum boost, loudness compensation on, coupled with say very high levels of L.F.E in a movie and high overall system volumes - a combination which would easily damage most HiFi speaker bass units - you'd really want a dedicated bass driver/subwoofer to handle that sort of load, and even then such a driver could be damaged if there was enough bass overload.
So just how clever is the ABL feature at idiot proofing the bass driver against mechanical overload; does it just reduce the bass boost re the equalisation feature at higher volumes, or can it also protect the driver against other bass overload conditions - I'd greatly appreciate a technical explanation if someone is able to give it, or has other in-depth knowledge of how this feature works and how it protects the bass driver from inadvertent mechanical overload.
Many thanks everyone
Kind regards
John...
Not sure about the implementation used in B&O active loudspeakers though. Almost all active loudspeakers have inbuilt protection against overload. However, varying the bass response at different signal levels still seems to be quite unique to B&O though.
I'd say it's pretty much the old loudness function that has been around for decades, only with a new name.
/ Johan
wonderfulelectric: Not sure about the implementation used in B&O active loudspeakers though. Almost all active loudspeakers have inbuilt protection against overload. However, varying the bass response at different signal levels still seems to be quite unique to B&O though.
Yes, the ABL circuit is patented and proprietary to B&O; unfortunately I can't comment on active speakers generally, as I've not owned a pair before.
Johan: I'd say it's pretty much the old loudness function that has been around for decades, only with a new name. / Johan
They were my exact thoughts also, until connecting them to my V1-40 also meant having an in-depth dig around in the more advanced menus of the surround sound processor and general setup of the V1-40.
It's worth noting (according to my dealer) that the V1 series is the first TV product to feature the new digital chassis; the BV11 is the second, albeit the first in the B&O 'proper' range as against the 'BeoPlay' range, but by and large the features re a plethora of adjustments are very similar. And in digging around, I came across something I haven't seen on an amplfier/surround sound processor in about 30 odd years; a loudness compensation setting - so it was clear the ABL was something else again.
Back in the analogue days, loudness compensation features on amplifiers in the separates world were very common, however whilst also compensating for the Fletcher Munson curve, re the ears decreased sensitivity to bass and treble at low volumes, they added noise and distortion, and with the aim of achieving the 'purest' signal possible, makers such as Linn and Naim eschewed both loudness compensation filters and tone controls as well, with the minimalist pursuit of a straight piece of wire with gain re an amplification concept being the goal towards 'better' sound reproduction.
However, fast forward 30 odd years, and DSP allows a lot of earlier concepts to be implemented without a noticeable performance loss re added noise and/or distortion, so given the thoroughness of B&O's R&D, whilst I was at first surprised to find a loudness compensation filter, I could also see the sense of it at the same time, as the Fletcher Munson curve is factual and well known.
Kind Regards
John
MartinW:Hi John - I believe your understanding of ABL is correct - at least it is the same as my understanding! To me it gives a well balanced boost to the bass at low levels, where many systems would just sound thin. As the volume goes up this boost is proportionally reduced to maintain a 'perfect' music balance. This is quite unlike 'loudness' Johan which basically spikes low end bass and high end treble at all volumes - a sound which can enhance lower quality loudspeakers but can be a bit tiring to listen to over long periods. I like loudness on with many speakers but preferred it off on my BL9's - and definitely off with BL5's. As for protection - B&O incorporate a thermal overload circuit into the active speakers that puts the speakers into a protection mode when they get too hot. I have seen numerous BL8000/BL6000 repairs where drivers have been blown but I have never seen this on any BL3, BL9 or BL5 speaker so I have always assumed that the ICEpower range has superior protection circuits.
As for protection - B&O incorporate a thermal overload circuit into the active speakers that puts the speakers into a protection mode when they get too hot. I have seen numerous BL8000/BL6000 repairs where drivers have been blown but I have never seen this on any BL3, BL9 or BL5 speaker so I have always assumed that the ICEpower range has superior protection circuits.
Hi Martin - thank you for your thoughts and experience.
To elaborate and expand a little upon my reasons for asking.....
I am hugely happy with my new Beolab 9's on both sonic grounds, but also as they are a finished audio/AV solution that steps right away from the world of audiophile obsessing, and delivers instead a completed, finished and balanced system to appeal to those who whilst they might like to know something of the ins and outs and wherefores of kit, but otherwise just much prefer to listen and enjoy the end result of the music or movie, rather than faffing about endlessly with the kit, as a kind of audiophile, or in some cases audiophool hobby, relevant to some though that may be.
It's been many years since I've owned new speakers; the subject of 'running them in' seems slightly contentious - another area for audiophile myths to self propagate perhaps. I did some reading about this, and it appears that the surrounds and spiders can settle down a little with early use - B&W for example claim about 15 hours for the mechanical effects to settle in the drivers, and for up to a week for temperature effects to stabilise, and for any seeming longer periods being more about the user getting used to the new sound, rather than any further inherent changes in the speaker taking place.
As to the method of running in - again opinions seem to vary - some say drive them harder than normal, others quieter than normal, and others to just drive them 'normally'...lol
In my case, being a bit of a recovering audiophile, and with a new and very expensive purchase, I've been ultra careful, so for the first couple of hours running, it was low level orchestral music, and after about three hours I bought the volume up to a still low, but more moderate level, and being very excited by my new purchase proceeded to listen for a good 10 hours at that sort of level till 4am in the morning!
On the second day of listening, still at low volumes relatively speaking, and playing some organ music, I was astonished and slightly concerned by the amount of low bass on low organ pedal notes, in the context of not wanting to put too much bass through them, being 'new' and all re the 'running in' etc.
So I did some comprehensive reading through the technical sound guide for the V1-40. There are seven factory pre-set sound 'modes', all of which can be individually customised. However, the one marked 'custom' is that which the sound guide notes to be a 'purist' setting for music listening, but even here the factory default is for loudness compensation to be 'on'. So, I turned it off in the custom mode, and found that for organ music the balance was better, and I had no fears about excessive bass on 'new' speakers 'running in' etc....
However, at the next listen, I was playing some string quartets/orchestral, and something about the magic of the sound had disappeared; I reset the custom sound mode back to factory default (i.e. Loudness compensation 'On') and the magic was restored.
I'm trying hard to move away from past audiophile obsessing, so as the sound guide mentioned the custom sound mode factory default (with loudness on) to offer the truest sound, I've left it as such from then on, and just accepted the much more powerful bass (when it is on a recording such as low organ pedal ranks) over what I have been used to with my previous system.
I wouldn't say the sound is unbalanced per se, just that the bass is quite prodigious, and I'm simply not used to that level of bass control and power out of my previous system. I also tried to ignore my concerns about speakers needing to be run in or babied whilst still new - whilst still being conservative with the volume control and continuing to listen at moderate, to now, with about 100 hours on them, normal, to a bit louder, but not REALLY loud levels.
I've also introduced movies; for the time being, I'm running in three channel mode - i.e. the V1-40 is doing the centre, and the Beolab 9's left and right fronts - the Bluray player outputs DD True HD and DTS HD Master Audio as 5.1 PCM; the TrueImage processing in the V1-40 outputs it as 3 channel audio - which of course also incorporates the L.F.E as well as the bass from all the channels being routed to the Lab 9's.
And it's here that I've had some anxious moments/concerns, hence my asking about the protection side of it with the ABL circuitry.
At first, I was able to play older movies, or movies without much L.F.E. to a level where the dialogue was clear and well balanced - usually at around 50 - 55 to perhaps a maximum of 60 on the volume control. However, some movies had some sudden surprises with L.F.E. effects that had me jumping on the volume control to drop the level back to around 45 or so to lessen the bass load on the speakers (that audiophile obsessing about babying new speakers again...lol) but of course, then the dialogue is a bit too low for clear intelligibility. As far as the sound mode is concerned, the picture and sound modes on the V1-40 I've both set to movie mode by default on the assigned Bluray player HDMI input - and for the movie sound mode, again the default is for loudness compensation to be on.
Last week, I played a new Bluray movie on the beginning of the XMen series - science fiction with lots of L.F.E. At around 45 on the volume, dialogue was too low, but the bass powerful.
Hmmm I thought, I can't keep babying them forever, and with 100 odd hours on them now, I should be able to play them to normal or louder levels with no issues, and the settings are all at recommended facttory default, so I upped the volume to a good dialogue level at 60 on the volume control.
So far so good, but.... there was a scene where suddenly the L.F.E surged to a level I would expect to hear from a high quality dedicated subwoofer.... but certainly not from a HiFi speaker, - at least not one that I've ever heard before - and simultaneously there was a sort of 'click' sound from the R.H. Channel - I panicked and jumped on the volume control fearing that the bass driver had bottomed out - i.e. the voice coil former had hit the back of the magnet plate.
So an audiophile anxiety moment or two followed, where I repeated the sequence several times whilst on my knees carefully listening to both speakers, and again in the normal seated position, and heard no deleterious sounds, apart from extraordinary bass such as would be expected from a dedicated sub, and not a HiFi speaker, and also that there were several click sounds in the actual sound track at around the same instance as the surge in L.F.E., - so I'm surmising that the sudden and most unexpectedly powerful and loud L.F.E. in combination with a sound effect in the sound track, co-mingled such as to make it seem as if it was the bass driver in distress.
Certainly with my previous system, currently ES Sony electronics and Naim SBL Fronts/Tannoy MX2 surround speakers, where I run them all 'large' i.e. they all handle the L.F.E. and there is no bass management (also with 'phantom' centre) I've never heard that level of bass/L.F.E before, but even so have had some frights where a click or pop in the sound track has co-mingled with very loud L.F.E. and caused a few frights when at high listening levels - that system is calibrated and I have listened at times on some movies up to 10db below dolby reference - i.e. 95db peaks.
Anyway, further listening to my new Lab 9's confirms that all is well, and that it was more of an recovering audiophile 'panic attack/anxiety moment' than any real problem with the speakers per se. Certainly when I demoed them in the shop prior to purchase, and with a V1-40 (almost certainly also at factory defaults) + Sony PS3 as the source, and again in a 3 channel mode, there were no issues on music up to around 70 on the volume, and at one point in some of the loud action sequences on the movie Avatar, the dealer cranked it up to 83 on the volume, and with no deleterious effects at all - I was quite astonished to be honest - in the passive world of separates, from my experience with such systems, there's no way you would get away with that sort of 'abuse' - active of course may be different, but not having owned active systems before I've not the experience to comment.
However, all speakers have limits, and I most certainly do not wish to inadvertently damage mine in any way, hence my asking about the protection side of things with the ABL circuitry.
I'm aware of the thermal overload protection, but in the case of sudden L.F.E. it's more of an impulse overload perhaps, where the driver could either jump forward out of the magnet gap, or rearwards to smack into the magnet back plate; either way likely to damage the driver, and I'm a bit anxious to know if the ABL circuitry protects against that sort of event.
Re the loudness compensation; from the technical sound guide for my V1-40, my impression/understanding is that the effect rolls in when the volume is lowered, and rolls out when you up the volume - albeit at what point in the overall volume control range this occurs is not made clear - rather than something that is consistent whatever the volume setting - but I could be wrong on this - certainly it's how loudness compensation filters/switches used to work back in the analogue days, albeit with DSP I'd expect it to be much more effective, and more or less like dynamic EQ - but I could be wrong again of course!
Well, i hope I haven't bored you all with my in-depth explanation to the background for my initial question about the ABL protection - I'm absolutely ecstatic with my new speakers, and probably just need to relax and enjoy the prodigious bass output, but audiophile concerns don't die easily, and I've had a few moments of anxiety re not wanting to accidentally damage the drivers due bass overload as mentioned - so if anyone is able to put my anxieties to rest due either an explanation of how the ABL circuitry works, or other experiences or recommended settings for the Lab 9's, I'd greatly appreciate hearing them...
Thanking you all for listening and sharing your knowledge and experiences...
John,
Stop worrying. It's been my experience that B&O build their speakers not to break, even under mild abuse. This is all part of the B&O experience - they're built for "dummies" (i.e. non-derogatory term for non-technical folks) - turn on the system and listen, immerse yourself in the music and forget about the technical bits. As the BL9s are not cheap, I can understand your concern with maintaining your investment, but they a robust, engineered system of amplifiers and drivers. They are built for people who don't give a second thought to "cranking it up to 11".
My experience with ABL is that reduces the bass according to sound level. It also causes most speakers to become "shouty" at high levels (the bass is turned down so the treble becomes more pronounced). I think the pops you heard were in the movie's soundtrack.
Here's some speculation on how ABL works: ABL is a function of the speaker, not the source. Except for the Lab5, volume is controlled by the input signal level coming from the source so I assume the speaker's amps are always be running with the same amplification. I would assume that the ABL is a circuit sitting between the cross-over and the bass amp that effectively attenuates the signal level to prevent damaging sound levels from reaching the amp/driver. As it is a circuit, it is working all the time so it doesn't matter if the signal comes from music, movie, sudden or gradual. Keep in mind, this is merely speculation, but, as a former engineer, this makes sense to me.
Stan
Stan:Stop worrying. It's been my experience that B&O build their speakers not to break, even under mild abuse. This is all part of the B&O experience - they're built for "dummies" (i.e. non-derogatory term for non-technical folks) - turn on the system and listen, immerse yourself in the music and forget about the technical bits. As the BL9s are not cheap, I can understand your concern with maintaining your investment, but they a robust, engineered system of amplifiers and drivers. They are built for people who don't give a second thought to "cranking it up to 11".
Indeed - people with a technical background will probably be more careful by nature and somewhat wary about using excessive levels... whereas some people just can't understand why you could not drive any technical & electronic device to the max. And the latter are of course, in a sense, right.
Stan:Here's some speculation on how ABL works: ABL is a function of the speaker, not the source. Except for the Lab5, volume is controlled by the input signal level coming from the source so I assume the speaker's amps are always be running with the same amplification. I would assume that the ABL is a circuit sitting between the cross-over and the bass amp that effectively attenuates the signal level to prevent damaging sound levels from reaching the amp/driver.
There's no full service manual for Beolab 9 (just a block diagram), but BL8000 manual shows it down to component level. There's still no description on how it works, but it's integrated into the crossover (which is just 2-way). It has an optical LED-LDR feedback system, with the LED apparently driven by an integrator network. I suppose it just averages the actual incoming bass level over some time constant, and controls the bass gain according to that.
BL9 manual has a block diagram, and ABL is again a separate unit but seems to control both bass & midrange levels. The actual protection circuitry is separate, with thermal feedback from the drivers, and probably level feedback as well (not clear from the manual).
In Beolab 5 (does it actually have ABL?) it would obviously be implemented completely in software.
(Sorry John, I haven't read your entire post yet - but will later, they are usually worth it )
--mika
Stan: John, Stop worrying. It's been my experience that B&O build their speakers not to break, even under mild abuse. This is all part of the B&O experience - they're built for "dummies" (i.e. non-derogatory term for non-technical folks) - turn on the system and listen, immerse yourself in the music and forget about the technical bits. As the BL9s are not cheap, I can understand your concern with maintaining your investment, but they a robust, engineered system of amplifiers and drivers. They are built for people who don't give a second thought to "cranking it up to 11". My experience with ABL is that reduces the bass according to sound level. It also causes most speakers to become "shouty" at high levels (the bass is turned down so the treble becomes more pronounced). I think the pops you heard were in the movie's soundtrack. Here's some speculation on how ABL works: ABL is a function of the speaker, not the source. Except for the Lab5, volume is controlled by the input signal level coming from the source so I assume the speaker's amps are always be running with the same amplification. I would assume that the ABL is a circuit sitting between the cross-over and the bass amp that effectively attenuates the signal level to prevent damaging sound levels from reaching the amp/driver. As it is a circuit, it is working all the time so it doesn't matter if the signal comes from music, movie, sudden or gradual. Keep in mind, this is merely speculation, but, as a former engineer, this makes sense to me. Stan
Hi Stan
Firstly, thank you so much for taking the time to read and absorb my very long post. I apologise for the length - it's a bit much to expect kind folks otherwise busy with work and life commitments to wade through something like that and respond - certainly I didn't plan for it to be so long,,, but as you can probably tell, I've been somewhat concerned about accidental damage to the bass drivers on my lovely new Lab 9's. Audiophile obsessions die hard...lol
I take the point about not worrying, with respect to B&O building their speakers to cope with the inadvertent abuse that some non technical users may dish out, which upon reflection I would agree with, and it gives me some comfort to feel that I likely haven't damaged the drivers with the sort of heavy bass/L.F.E. in the situation as I outlined in my long post.
I'm not an electronics engineer, albeit I've played around in a very hands on way with mechanical things and amateur electronics since a very young age, and have been involved in the HiFi hobby for over 40 years, so have learnt a few things along the way, but always prefer to hear much more experienced advise than rely upon my own limited experience, so doubly appreciate your comments as a former engineer - thank you.
Certainly your speculation as to how the ABL works makes a lot of sense - one would hope it would protect the bass driver from mechanical overload in all situations, - not just when it is either boosting or lowering the bass re it's equalisation feature.
Thank you so much again for your thoughtful, and helpful comments Stan
Thanks for the kind words. I'm just "paying it forward". Over the years, many kind people have helped me on this forum so I try to help when I can.
tournedos: Stan:Stop worrying. It's been my experience that B&O build their speakers not to break, even under mild abuse. This is all part of the B&O experience - they're built for "dummies" (i.e. non-derogatory term for non-technical folks) - turn on the system and listen, immerse yourself in the music and forget about the technical bits. As the BL9s are not cheap, I can understand your concern with maintaining your investment, but they a robust, engineered system of amplifiers and drivers. They are built for people who don't give a second thought to "cranking it up to 11". Indeed - people with a technical background will probably be more careful by nature and somewhat wary about using excessive levels... whereas some people just can't understand why you could not drive any technical & electronic device to the max. And the latter are of course, in a sense, right. Stan:Here's some speculation on how ABL works: ABL is a function of the speaker, not the source. Except for the Lab5, volume is controlled by the input signal level coming from the source so I assume the speaker's amps are always be running with the same amplification. I would assume that the ABL is a circuit sitting between the cross-over and the bass amp that effectively attenuates the signal level to prevent damaging sound levels from reaching the amp/driver. There's no full service manual for Beolab 9 (just a block diagram), but BL8000 manual shows it down to component level. There's still no description on how it works, but it's integrated into the crossover (which is just 2-way). It has an optical LED-LDR feedback system, with the LED apparently driven by an integrator network. I suppose it just averages the actual incoming bass level over some time constant, and controls the bass gain according to that. BL9 manual has a block diagram, and ABL is again a separate unit but seems to control both bass & midrange levels. The actual protection circuitry is separate, with thermal feedback from the drivers, and probably level feedback as well (not clear from the manual). In Beolab 5 (does it actually have ABL?) it would obviously be implemented completely in software. (Sorry John, I haven't read your entire post yet - but will later, they are usually worth it )
Thank you so much Tournedos for taking the time to read my long post, and to check with the manuals.
I do apologise about the length of the post, and hope it doesn't seem to long winded a discussion about ABL and my interest and reasons for investigating how it works, but I've been a bit concerned to be honest about the prodigious bass output from what is after all a HiFi speaker, not a dedicated sub woofer, and the risks of inadvertent driver damage through bass overload accordingly.
And of course, the difficulty in having a technical background in an amateur/hobbyist way as I do, is that it's easy to worry about things when you don't have all the facts or knowledge of how something works, whereas a non-technical person would probably be happier in their relative ignorance so to speak, so I'm probably worrying where I really shouldn't - B&O almost certainly know what they're doing with the design and engineering of their speakers - as Stan points out, some users will doubtless think nothing of cranking it up to 11, and B&O will likely engineer their speakers to cope with this.
I'm interested in what you see on the Beolab 9 service manual - if you're able once you've waded through my very lengthy post (sorry ) to comment further, I'd greatly appreciate it.
All this happened last week BTW, and I was concerned enough to visit my very helpful dealer and ask advice, before bothering the membership here.
Unfortunately, they are not able to offer a technical insight into how the ABL works either, (which is why I decided to ask the membership here for some technical advise or other experience/opinion if possible) but some anecdotal comments were interesting.
Their viewpoint was that if you are silly enough, and drive them hard enough and long enough, you can damage the likes of Lab 9's or 5's, but generally speaking, providing one is not completely stupid, there should be no problems.
By being silly - one customer apparently with a pair of Lab 5's, turned the volume to max, muted the system, put on the Telarc disc of the Tchaikovsky 1812 overture, complete with digital cannons (and obviously not heeding the warning on the discs about the levels going down to 5hz at speaker destroying levels!) cued up the disc, and took the mute off; - BANG - exit one Lab 5 bass driver.....
According to the dealer, the ABL function works with respect to time, so if you do silly things like that, it is actually possible to damage a driver - as happened in that particular case.
Another customer, owner of a pair of Beolab 9's, had his two teenage sons use them for a party - more or less maximum volume for a good 6 hours or so, with pauses when the speaker overheated and cut out - result, one damaged midrange driver in a Lab 9.
By contrast, it was pointed out that the showroom is much larger than my apartment, complete with traffic noise etc, and they drive the systems there regularly to very high volumes without issue, albeit obviously not for hours on end.
Indeed, the manager of the store is himself an 'ex' audiophile and owns three pairs of Lab 5's + projector etc, and mentioned that in some demos he used the infamous Sheffield Labs drum test disc, driving the system on both 5's and 9's to live drum-kit levels (around max volume) with no issues.
So, their opinion was more or less that unless one is completely clueless and silly, the system is well able to take high levels of volume and bass etc, with no issues, and that I was probably just being a paranoid ex audiophile....LOL - they're really nice people and exceptionally helpful BTW...both of the two main staff have a lot of audio experience behind them - which is extremely helpful - I could not be more delighted with the service.
So really, Stans' advice and the comments from the dealer basically correlate, so I should probably stop worrying - but if a technical explanation could be found re the ABL workings, I'd very much like to avail myself of that information.
I will say, that the only other HiFi speaker that I've heard (apart from dedicated high quality sub woofers) that offers anything like the ability of the Lab 9 on movie L.F.E. (and of course exceeds it) is the Lab 5.
In many ways, having heard the 5's much more extensively in demos than the 9's, the 9's remind me now as an owner, in many ways of being a 'mini' or scaled down, Lab 5. The sound really is that good! - they are quite amazing speakers, and I oft wonder if the more technically illiterate owners, otherwise delighted with them, realise just how good they are when compared to the audiophile mainstream offerings in the speaker world. Certainly I've heard nothing in their price range that comes close, and even many thousands above them in pricing level - that B&O is ignored by many audiophiles is simply their loss, and 'our' gain.
There's a learning curve going on for me with the performance and the prodigious bass - hence some concern and questioning, no doubt influenced by past audiophile experiences - but otherwise I'm exceedingly happy with my new purchase; albeit I would still like technical info on the ABL working should it be available, so that I can fully relax and take both yours, Stans and the dealers advice on board and stop worrying!!
Thank you again Tournedos for taking the time to read and absorb my long post and to respond - this is a wonderful forum and I'm very grateful and lucky to be a member of it, and to be a B&O owner with all the advantages that confers on a recovering audiophile!
Kind regards and many thanks
John: From this description, my guess is that technically, where the bass drivers starts to roll of re frequency response, the power and amplitude response is boosted, so as to extend the overall frequency response of the speaker; conversely, at higher volume levels, the boost is reduced so as not to overload the driver. I am curious though, and would like to find out as to whether this feature protects the bass driver against mechanical overload/damage from other sources of bass boost, such as tone controls (bass) at maximum boost, loudness compensation on, coupled with say very high levels of L.F.E in a movie and high overall system volumes - a combination which would easily damage most HiFi speaker bass units - you'd really want a dedicated bass driver/subwoofer to handle that sort of load, and even then such a driver could be damaged if there was enough bass overload. So just how clever is the ABL feature at idiot proofing the bass driver against mechanical overload; does it just reduce the bass boost re the equalisation feature at higher volumes, or can it also protect the driver against other bass overload conditions - I'd greatly appreciate a technical explanation if someone is able to give it, or has other in-depth knowledge of how this feature works and how it protects the bass driver from inadvertent mechanical overload.
Hi John,
You are mostly right - and partly wrong, and that depends on exactly which product we're talking about. So, rather than answer your question directly, I'll explain it differently. You'll note however, that some of what I say here repeats what you've already assumed to be true. Also forgive me if I underestimate your knowledge - I'm intentionally starting low.
There is no one technical definition for ABL, since it is in continual evolution. Speaking broadly, we could say that it reduces the low frequency content sent to the loudspeaker driver(s) (i.e. the woofer) when the loudspeaker is asked to play loudly - but even this is partially inaccurate.
It is not the case that this replaces a "loudness function" which may or may not be equalising for Equal Loudness Contours (sometimes called "Fletcher-Munson Curves"). However, since the bass is pulled back when things get loud, it is easy to assume this to be true.
When we are doing the sound design for a loudspeaker (which is based both on measurements and listening), we make sure that we are operating at a listening level that is well within the linear behaviour of the loudspeaker and its components. This means that the drivers (i.e. the woofer and tweeter) aren't being asked to move too far, the amplifier is no where near clipping, the power supply is well within its limits, and nothing (not the power supply, the amplifiers, or the voice coils) is getting so hot that the loudspeaker's behaviour is altered. This is what is meant by "linear" - it's another word for "predictable", (Not to mention the fact that if we were listening to loudspeakers at high levels all the time, we would get increasingly bad at our jobs due to hearing loss.)
So, we do the tuning at that low-ish listening level where we know things are behaving - also note that we always do it at the same calibrated level every time for every loudspeaker so that we don't change sound design balance due to shifts associated with equal loudness contours. (If you tune a loudspeaker when it's playing loudly, you'll wind up with a loudspeaker with less bass than if you tuned it quietly. This is because you're automatically compensating for differences in your own hearing at different listening levels.)
Once that tuning is done, then we go back to the measurements to see where things will fall apart. For example, in order to compensate for the small cabinet of the BeoSound 8, we increase the amount of bass that we send to the amplifiers for the woofers as part of the sound design. If we just left that bass boost in when you turn up the volume, the poor little thing would go up in smoke - or at least sound very bad. This could be because the woofer is being pushed/pulled beyond its limits, or because the amplifier clips or the power supply runs out of steam or something else. (Note that BeoSound 8's do not actually run on steam - but they do contain the magic smoke that keeps all audio gear functioning properly.) So, we put the loudspeaker in a torture chamber, put on some dance music (or some slightly more-boring modified pink noise) and turn up the volume.... While that's playing, we're continually monitoring the signal that we're playing, the driver excursion, the demands on the electronics (i.e. the amp's, DAC's, power supply, etc) and the temperature of various components in the loudspeaker, along with other parameters that I can't think of right now...
Armed with that information, we are able to "know" what those parameters are and how they relate to the characteristics of the music that is being played (i.e. how loud it is, in various frequency bands, for how long, in both the short term and the long term). This means that, when you play music on the loudspeaker, it "knows" how hot it is at various locations inside, what the velocity of the air in the port is (if it has a port), the driver excursion, amplifier demands, power supply demands, and so on. (The actual list varies according to product - these are just some examples...) So, when something gets close to a maximum (i.e. the amplifier starts to get too hot, or the woofer is nearing maximum allowable excursion, or the air velocity in the port is nearing an unacceptable level) then SOMETHING will be pulled back.
WHAT is pulled back? It depends on the product and the conditions at the time you're playing the music. It could be a band of frequencies in the bass region, it could be the level of the woofer. In a worst-case-last-ditch situation, you might wind up shutting down the loudspeaker (I've done this! :-) )
HOW is it pulled back (i.e. how quickly and by how much)? That also depends on the product and some decisions we made during the sound design process, as well as what kind of state-of-emergency your loudspeaker is in (some people are very mean to loudspeakers...).
Note that all this is done based on the signals that the loudspeaker is being asked to produce. So it doesn't know whether you've turned up the bass or the volume - it just knows you're asking it to play this signal right now and what the implications of that demand are on the current conditions (voice coil temperature, for example) This is similar to the fact that the seat belts in my car don't know why the car is stopping quickly - maybe it's because I hit the brakes, maybe it's because I hit a concrete wall - the seat belts just lock up when they're asked to move too quickly. Your woofer doesn't know the difference between Eminem and Stravinsky with a bass boost - it just knows it's hot and it doesn't want to get hotter.
It's important to note that some of what I've said here is not true for some products. The analogue loudspeakers cannot have the same self-knowledge as the digital loudspeakers because they don't have the same "processing power". We make every effort to ensure that you get as much as is possible out of your loudspeaker while still ensuring that you can't do any real damage to it. However, it's fair to say that, the more recent the model, the closer we are able to get to the maximum limits of the total system.
I hope that this answers your question(s) and clears things up a little - although I know I didn't actually give you the details of the specific question you asked...
Cheers
-geoff
Wonderful, thanks Geoff
Interesting description, I'm assuming my old Lab 8000's have the least intelligent implementation...but I also never assumed ABL was a loudness contour either.
Interesting thing about loudness contours, a number of old preamps and receivers I've had used an interesting implementation in that you set the volume to your usual loudish listening level, then from then on turn the volume down and up using the loudness control know. The loudness knob is at max clockwise position when you set the volume, then when you turn it down to a softer level it slowly applies more and more loudness contour the softer you set the sound level. Clever, more correct than the sledgehammer approach most things have with a simple on/off for loudness.
Still, to my ears the most useful implementation of loudness I've encountered has been on my BS9000. When listening at night and not wanting to disturb my wife, I use it listening at some quite low levels, and it seems to be pretty well implemented, as it doesn't sound like loudness it just subtly makes the whole system sound good at low levels. I don't think many mass market loudness contours are that well calibrated.
Jeff
I'm afraid I'm recovering from the BeoVirus.
What a detailed and thorough explanation Geoff!
I assume by "we" you mean you and your team of acoustic engineers. That's nice to know somebody from the inside is watching closely what is going on in the forum.
Normal 0 21 false false false DA JA X-NONE
Thanks a lot for that detailed description of ABL.
It does also tell me another thing, and that is what active speakers can ”give” the engineers.
With active speakers you seem to be so much more in control of how the speakers must ”handle” the music, and now I fully understand why B&O prefer active speakers.
beolion:With active speakers you seem to be so much more in control of how the speakers must ”handle” the music, and now I fully understand why B&O prefer active speakers.
They went with active design before they were able to tweak so easily with newer tech. An active crossover is before the amplification (i.e. at line level), and you then have dedicated amplifiers to each driver. As a result, you have much less distortion, and have a much more responsive and accurate reproduction. That in itself is most likely why B&O went for active design. The rest is important, but not the reason. If it was the reason, it wouldn't matter much just how powerful those amps are. However, B&O have chosen to power the various drivers with enough power to make a difference. So, in my book, they not just doing this for convenience to themselves. They actually care about accurate reproduction.
In other words, they could just as easily use a passive design and EQ for the same "ease of tweaking", but we're lucky they haven't taken that route.
Geoff Martin: John: From this description, my guess is that technically, where the bass drivers starts to roll of re frequency response, the power and amplitude response is boosted, so as to extend the overall frequency response of the speaker; conversely, at higher volume levels, the boost is reduced so as not to overload the driver. I am curious though, and would like to find out as to whether this feature protects the bass driver against mechanical overload/damage from other sources of bass boost, such as tone controls (bass) at maximum boost, loudness compensation on, coupled with say very high levels of L.F.E in a movie and high overall system volumes - a combination which would easily damage most HiFi speaker bass units - you'd really want a dedicated bass driver/subwoofer to handle that sort of load, and even then such a driver could be damaged if there was enough bass overload. So just how clever is the ABL feature at idiot proofing the bass driver against mechanical overload; does it just reduce the bass boost re the equalisation feature at higher volumes, or can it also protect the driver against other bass overload conditions - I'd greatly appreciate a technical explanation if someone is able to give it, or has other in-depth knowledge of how this feature works and how it protects the bass driver from inadvertent mechanical overload. Hi John, You are mostly right - and partly wrong, and that depends on exactly which product we're talking about. So, rather than answer your question directly, I'll explain it differently. You'll note however, that some of what I say here repeats what you've already assumed to be true. Also forgive me if I underestimate your knowledge - I'm intentionally starting low. There is no one technical definition for ABL, since it is in continual evolution. Speaking broadly, we could say that it reduces the low frequency content sent to the loudspeaker driver(s) (i.e. the woofer) when the loudspeaker is asked to play loudly - but even this is partially inaccurate. It is not the case that this replaces a "loudness function" which may or may not be equalising for Equal Loudness Contours (sometimes called "Fletcher-Munson Curves"). However, since the bass is pulled back when things get loud, it is easy to assume this to be true. When we are doing the sound design for a loudspeaker (which is based both on measurements and listening), we make sure that we are operating at a listening level that is well within the linear behaviour of the loudspeaker and its components. This means that the drivers (i.e. the woofer and tweeter) aren't being asked to move too far, the amplifier is no where near clipping, the power supply is well within its limits, and nothing (not the power supply, the amplifiers, or the voice coils) is getting so hot that the loudspeaker's behaviour is altered. This is what is meant by "linear" - it's another word for "predictable", (Not to mention the fact that if we were listening to loudspeakers at high levels all the time, we would get increasingly bad at our jobs due to hearing loss.) So, we do the tuning at that low-ish listening level where we know things are behaving - also note that we always do it at the same calibrated level every time for every loudspeaker so that we don't change sound design balance due to shifts associated with equal loudness contours. (If you tune a loudspeaker when it's playing loudly, you'll wind up with a loudspeaker with less bass than if you tuned it quietly. This is because you're automatically compensating for differences in your own hearing at different listening levels.) Once that tuning is done, then we go back to the measurements to see where things will fall apart. For example, in order to compensate for the small cabinet of the BeoSound 8, we increase the amount of bass that we send to the amplifiers for the woofers as part of the sound design. If we just left that bass boost in when you turn up the volume, the poor little thing would go up in smoke - or at least sound very bad. This could be because the woofer is being pushed/pulled beyond its limits, or because the amplifier clips or the power supply runs out of steam or something else. (Note that BeoSound 8's do not actually run on steam - but they do contain the magic smoke that keeps all audio gear functioning properly.) So, we put the loudspeaker in a torture chamber, put on some dance music (or some slightly more-boring modified pink noise) and turn up the volume.... While that's playing, we're continually monitoring the signal that we're playing, the driver excursion, the demands on the electronics (i.e. the amp's, DAC's, power supply, etc) and the temperature of various components in the loudspeaker, along with other parameters that I can't think of right now... Armed with that information, we are able to "know" what those parameters are and how they relate to the characteristics of the music that is being played (i.e. how loud it is, in various frequency bands, for how long, in both the short term and the long term). This means that, when you play music on the loudspeaker, it "knows" how hot it is at various locations inside, what the velocity of the air in the port is (if it has a port), the driver excursion, amplifier demands, power supply demands, and so on. (The actual list varies according to product - these are just some examples...) So, when something gets close to a maximum (i.e. the amplifier starts to get too hot, or the woofer is nearing maximum allowable excursion, or the air velocity in the port is nearing an unacceptable level) then SOMETHING will be pulled back. WHAT is pulled back? It depends on the product and the conditions at the time you're playing the music. It could be a band of frequencies in the bass region, it could be the level of the woofer. In a worst-case-last-ditch situation, you might wind up shutting down the loudspeaker (I've done this! :-) ) HOW is it pulled back (i.e. how quickly and by how much)? That also depends on the product and some decisions we made during the sound design process, as well as what kind of state-of-emergency your loudspeaker is in (some people are very mean to loudspeakers...). Note that all this is done based on the signals that the loudspeaker is being asked to produce. So it doesn't know whether you've turned up the bass or the volume - it just knows you're asking it to play this signal right now and what the implications of that demand are on the current conditions (voice coil temperature, for example) This is similar to the fact that the seat belts in my car don't know why the car is stopping quickly - maybe it's because I hit the brakes, maybe it's because I hit a concrete wall - the seat belts just lock up when they're asked to move too quickly. Your woofer doesn't know the difference between Eminem and Stravinsky with a bass boost - it just knows it's hot and it doesn't want to get hotter. It's important to note that some of what I've said here is not true for some products. The analogue loudspeakers cannot have the same self-knowledge as the digital loudspeakers because they don't have the same "processing power". We make every effort to ensure that you get as much as is possible out of your loudspeaker while still ensuring that you can't do any real damage to it. However, it's fair to say that, the more recent the model, the closer we are able to get to the maximum limits of the total system. I hope that this answers your question(s) and clears things up a little - although I know I didn't actually give you the details of the specific question you asked... Cheers -geoff
Hi Geoff
I would like to say that it is an absolute delight and honour to have your input on the forums - particularly such a detailed and insightful post - and having some idea of the kind of workload and responsibilities your role at B&O would entail, I can only offer my sincere and very grateful thanks for your taking the time to write and address my personal concerns as a new and very proud B&O owner, but also for the knowledge re the principles behind the workings of ABL imparted to everyone else.
I would like to suggest the Mods perhaps save the information re ABL as part of the reference information on this site for some of the technologies that B&O use - I found it extremely helpful, and very interesting indeed.
I've been 'into' sound and audio for a long time at an amateur level; born out of my love of, and study of music (piano, trumpet and voice - all in the classical domain). I've not been an atypical audiophile box-swapper, preferring to buy once and buy right, but certainly for a period started to get caught up in a lot of the audiophile obsessive and dubious rituals aimed at 'improving' the sound, but ultimately found that they took one away from the music, and re-focused ones attention on what the kit is doing to and with the music, rather than enjoying the music on an emotional and intellectual level per se.
I would like to just say that as a newcomer to B&O with the purchase of a new V1-40 earlier this year, and now a new pair of BeoLab 9's, I feel as if I'm finally where I want to be with a HiFi/AV system at last - I find the performance of the Lab 9's when assessed on musical criteria i.e. vocal and instrumental timbral detail and naturalness, spatial perspectives close to what I hear in real life, the outstanding reproduction of musical dynamics etc, coupled with easily the most user friendly, fiddle free system I've ever owned, and with customer service at the highest levels, I don't think I could be more delighted with both my purchase and B&O as a brand.
Some audiophile habits die hard, re worrying about bass levels and system durability on movie soundtrack heavy L.F.E. etc, as I had been and which caused me to post here, and I do find the performance of the Lab 9's extraordinary in this regard - more like a high performance dedicated sub such as a Velodyne DD15 than a HiFi speaker - but overall I feel as if most of my separates audiophile thinking, where you could be listening to music and finding oneself musing, "perhaps I could improve the sound if I changed this cable etc" rather than being absorbed by the music, has been more or less banished - I'm enjoying the music and movies from my new system to a much, much higher level than anything I've ever owned - and, oh Joy!, no audiophile anxieties or obsessive fiddling about with the kit required!
I'd also mention I'm a huge pipe organ fan, and listening to some of my favourite Bach recordings on Silbermann instruments, or large scale romantic works on my favourite Cavielle-Coll instruments - I'm in Heaven! - the sound is just awesome!
So please accept my very grateful thanks and appreciation for your most interesting and thorough explanation of the philosophy and engineering behind ABL, but also the whole approach to design and manufacture at B&O - there is simply nothing available in the passive speaker separates audiophile world that could offer that sort of combination of performance and control in a speaker when viewed as a total system - and the design and engineering detail that you go to, simply cements in my mind the sheer overall value of my investment, and makes me doubly proud as an B&O owner.
Thanks again so very much for your time and most helpful comments
tournedos: Wonderful, thanks Geoff
+ 10
Great post, John
Jeff: Interesting description, I'm assuming my old Lab 8000's have the least intelligent implementation...but I also never assumed ABL was a loudness contour either. Interesting thing about loudness contours, a number of old preamps and receivers I've had used an interesting implementation in that you set the volume to your usual loudish listening level, then from then on turn the volume down and up using the loudness control know. The loudness knob is at max clockwise position when you set the volume, then when you turn it down to a softer level it slowly applies more and more loudness contour the softer you set the sound level. Clever, more correct than the sledgehammer approach most things have with a simple on/off for loudness. Still, to my ears the most useful implementation of loudness I've encountered has been on my BS9000. When listening at night and not wanting to disturb my wife, I use it listening at some quite low levels, and it seems to be pretty well implemented, as it doesn't sound like loudness it just subtly makes the whole system sound good at low levels. I don't think many mass market loudness contours are that well calibrated.
Hi Jeff
Very interesting comments
Years ago, I owned a CA800 Yamaha amp - 2 channel stereo, switchable Class A/Class AB, and it had a very similar arrangement. One turned up the volume to what one wanted, and when needing to reduce it, one turned the loudness compensation knob clockwise - which lowered the volume and the midrange, leaving the bass and treble effectively boosted at the lower listening levels.
I found most other amps implementation of loudness compensation in the analogue world a bit crude to be honest; one often found a point where with the loudness switched out at a particular volume the sound was too thin, and with it switched in for the same volume level the sound was too OTT re the bass and treble.
Thus far, the implementation in the V1-40 seems very natural - as I understand it these loudness compensation features are supposed to automatically lower the perception of bass and treble as the volume goes up, so it should theoretically perhaps be a form of dynamic EQ - certainly I haven't as yet picked a point where it is either too much or too little re it's effect, as previously found in the analogue domain - I can only think this is in part due to the efficacy B&O's implementation and the advantages of DSP over analogue signal processing.
I agree that mass market loudness contours are not very well calibrated - at least in my experience.
Out of interest, do you switch it off when you listen at louder volumes, or just let it taper its effect away (as I believe it's designed to do) as you turn the volume up?
John....
I typically only use the loudness at lower levels, and it doesn't seem to gradually taper off on the BS9000 at higher volume levels. Still and all, it's useful, as is the ability to set the tone controls remotely. I don't understand the audiophile aversion to tone controls, especially as they often tailor sound in ways that aren't adjustable with odd cables and such. On the BS9000 the controls are wonderfully useful, hit a bright CD, one notch down on treble seems to cure it without making it dull, bass heavy, cut it a click or two, or boost it, they seem to be well calibrated at least to the Lab 8000's I use.
Geoff,
Thank you for such a thorough overview of the entire speaker test & tune process - very informative.
It's very interesting to hear that you and your team infer the excursion of drivers for the production model speakers. No doubt you use one of those cool laser vibrometers for measuring driver excursion in testing!
When will we start seeing servo driven loudspeakers from B&O? I think with those you could have better real-time excursion self-knowledge.
Beo4 'til I die!
wonderfulelectric:I assume by "we" you mean you and your team of acoustic engineers.
Sorry - I should have been more specific. Typically, these days for a given product, there is a "core" of three or four people within the acoustics department who work directly on the loudspeaker. These are the acoustical engineer, the DSP engineer and the sound designer. Of course, there is a lot of communication with people from other departments, like the mechanical engineers, the electrical engineers, the power amp and power supply people - and the visual designers.
So, when I said "we" I guess I was referring to that core team of 3 people from the acoustics department. Or maybe I just meant "we at B&O". :-)
John:Thanks again so very much for your time and most helpful comments
You're welcome! Glad to hear that the explanation answered your question. I'm also very happy to hear that you're happy with your system!
John: Thus far, the implementation in the V1-40 seems very natural - as I understand it these loudness compensation features are supposed to automatically lower the perception of bass and treble as the volume goes up, so it should theoretically perhaps be a form of dynamic EQ - certainly I haven't as yet picked a point where it is either too much or too little re it's effect, as previously found in the analogue domain - I can only think this is in part due to the efficacy B&O's implementation and the advantages of DSP over analogue signal processing.
Hi again,
If you look in the Advanced Menus of the V1, you'll see that you have the option to "tweak" the loudness compensation curves. The factory default settings are +12 dB on the Bass and +9 dB on the treble at the lowest volume levels. At high volume levels, there is (of course) no boost applied to either. On a medium volume level, the boosts will be something less than +12/+9.
However, if you feel that this default setting is too much or too little, you can change the values to your taste.
For more info on this, check out the Technical Sound Guide available on the beoplay.com website.
Geoff Martin: John: Thus far, the implementation in the V1-40 seems very natural - as I understand it these loudness compensation features are supposed to automatically lower the perception of bass and treble as the volume goes up, so it should theoretically perhaps be a form of dynamic EQ - certainly I haven't as yet picked a point where it is either too much or too little re it's effect, as previously found in the analogue domain - I can only think this is in part due to the efficacy B&O's implementation and the advantages of DSP over analogue signal processing. Hi again, If you look in the Advanced Menus of the V1, you'll see that you have the option to "tweak" the loudness compensation curves. The factory default settings are +12 dB on the Bass and +9 dB on the treble at the lowest volume levels. At high volume levels, there is (of course) no boost applied to either. On a medium volume level, the boosts will be something less than +12/+9. However, if you feel that this default setting is too much or too little, you can change the values to your taste. For more info on this, check out the Technical Sound Guide available on the beoplay.com website. Cheers -geoff
As always, I deeply appreciate and thank you for your further comments and advice, as I'm also sure does everyone here.
I have availed myself of a copy of the Technical sound guide, and have been studying it in depth - thank you for the reference.
I'm tempted to ask a couple of questions, but hesitate slightly as I'm sure that answering the technical questions of owners doesn't quite come into your job remit, and I hate to take up the time of hard working professionals.
But at the risk of being a nuisance, and to satisfy my audiophile angst..lol.. I'll ask anyway; please feel free to ignore them if you're too busy with other work commitments etc.
1) I've not come across loudness compensation in 30 odd years, since back in the analogue days. I note it is the factory default for it to be on in both the custom sound mode setting (which I'm using for a two channel 'pure' music mode as the sound guide suggests) and for the movie sound mode (which I'm using for Bluray movies) on my V1-40, and with all sound modes set at factory default values.
Question: would you advise switching the loudness compensation on and off for low, as against normal to loud listening, as required, OR leaving it on all the time and tweaking the advanced settings re the loudness compensation curves to suit as suggested? I'm using 55 - 60 re a volume setting for music, and similar for movies, so would assume from your comments re medium volume levels, the loudness compensation would still be having some effect at these volume settings that I'm using currently for room filling, but not excessively loud levels, in my 5 x 4 metre, carpeted concrete floor space, with double brick painted walls and concrete ceiling (an atypical apartment).
2) I've been astonished by the amount of L.F.E the Lab 9's deliver when the effects are there in great strength on a movie sound track (using movie sound mode at factory default, running in 3 channel mode with V1-40 + Lab 9's, at a volume level of 60 and using a Bluray disc via HDMI.)
I note from the technical sound guide, that with a Lab 9, and with respect to bass management, low bass is only filtered/panned off to a Lab 5, and not to any other speaker in the B&O portfolio including a Beolab 2 subwoofer. I note also that the low frequency response circa -10db ref midrange for the BeoLab 9 is 28hz, and for the Beolab 2 subwoofer, 25hz.
Question: Apart from being likely to be able to play louder, lower and for longer in the case of the Beolab 2 subwoofer, would there be any likely advantage in adding an Beolab 2 subwoofer to my system? I assume from my interpretation of the technical sound guide that it would handle the L.F.E. only, and hence take some of the load off the Beolab 9's, but provided my Beolab 9's are up to the task of handling movie L.F.E. both in performance and reliability/durability terms, I would rather save the funds towards Beolab 3's as intended surrounds, and (please God!) BeoLab 5's later on if at all possible as my main system speakers, and moving the Lab 9's to the surround position.
Again Geoff, I greatly appreciate your extremely knowledgeable expertise and experience; please don't let yourself get caught up in the angst of an recovering audiophiles questions if you are very busy with work commitments etc, but if you are able to make some small comment, I would dearly love to hear of your expert advice, and trust I haven't 'hit' you with an unfair plethora of requests for opinion and advice etc.
Respectfully and gratefully yours
Sorry it took a while to get back to you - it's been a busy week. I'll try to answer as best I can.
John: 1) I've not come across loudness compensation in 30 odd years, since back in the analogue days. I note it is the factory default for it to be on in both the custom sound mode setting (which I'm using for a two channel 'pure' music mode as the sound guide suggests) and for the movie sound mode (which I'm using for Bluray movies) on my V1-40, and with all sound modes set at factory default values. Question: would you advise switching the loudness compensation on and off for low, as against normal to loud listening, as required, OR leaving it on all the time and tweaking the advanced settings re the loudness compensation curves to suit as suggested? I'm using 55 - 60 re a volume setting for music, and similar for movies, so would assume from your comments re medium volume levels, the loudness compensation would still be having some effect at these volume settings that I'm using currently for room filling, but not excessively loud levels, in my 5 x 4 metre, carpeted concrete floor space, with double brick painted walls and concrete ceiling (an atypical apartment).
John: 2) I've been astonished by the amount of L.F.E the Lab 9's deliver when the effects are there in great strength on a movie sound track (using movie sound mode at factory default, running in 3 channel mode with V1-40 + Lab 9's, at a volume level of 60 and using a Bluray disc via HDMI.) I note from the technical sound guide, that with a Lab 9, and with respect to bass management, low bass is only filtered/panned off to a Lab 5, and not to any other speaker in the B&O portfolio including a Beolab 2 subwoofer. I note also that the low frequency response circa -10db ref midrange for the BeoLab 9 is 28hz, and for the Beolab 2 subwoofer, 25hz. Question: Apart from being likely to be able to play louder, lower and for longer in the case of the Beolab 2 subwoofer, would there be any likely advantage in adding an Beolab 2 subwoofer to my system? I assume from my interpretation of the technical sound guide that it would handle the L.F.E. only, and hence take some of the load off the Beolab 9's, but provided my Beolab 9's are up to the task of handling movie L.F.E. both in performance and reliability/durability terms, I would rather save the funds towards Beolab 3's as intended surrounds, and (please God!) BeoLab 5's later on if at all possible as my main system speakers, and moving the Lab 9's to the surround position.
Your interpretation of the Technical Sound Guide is correct. You've noticed that the Bass Management will not remove bass from a BL9 and send it to a BL2. However, you'll also note that a BL2's bass will not be sent to a BL9. This is because, if you average over a "wide" frequency range (albeit restricting yourself to low frequencies) you'll see that they are roughly equally capable. However, since you probably have TWO BeoLab 9's, they share the work, and thus certainly gives you more bass capability than you would have from a single BeoLab 2.
The low frequency range limits that you quote there are only true at low listening levels below the ABL thresholds. This number tells more about the sound design of the loudspeaker than its performance. In other words, it tells you a little about how low in frequency we're pushed the tuning when things are quiet, but it doesn't give you any information about how loud the loudspeaker can play bass.
I hope that this answers your questions.
Geoff Martin: Hi John, Sorry it took a while to get back to you - it's been a busy week. I'll try to answer as best I can. John: 1) I've not come across loudness compensation in 30 odd years, since back in the analogue days. I note it is the factory default for it to be on in both the custom sound mode setting (which I'm using for a two channel 'pure' music mode as the sound guide suggests) and for the movie sound mode (which I'm using for Bluray movies) on my V1-40, and with all sound modes set at factory default values. Question: would you advise switching the loudness compensation on and off for low, as against normal to loud listening, as required, OR leaving it on all the time and tweaking the advanced settings re the loudness compensation curves to suit as suggested? I'm using 55 - 60 re a volume setting for music, and similar for movies, so would assume from your comments re medium volume levels, the loudness compensation would still be having some effect at these volume settings that I'm using currently for room filling, but not excessively loud levels, in my 5 x 4 metre, carpeted concrete floor space, with double brick painted walls and concrete ceiling (an atypical apartment). Personally, I would suggest that you leave the Loudness function ON and, if you're not satisfied with the factory defaults, tweak the two values in the Advanced Menus to suit your tastes. The best way to do this is to play pink noise (you can find this as a downloadable file online - if not, Lady Gaga's "Just Dance" will serve as a substitute...) at a high-ish volume (55 is probably high enough) and then turn down the volume. You should hear the same balance between the bass, midrange and treble at all volume settings on the way down. If not, then tweak accordingly. Two things to note: - the Loudness function is there to compensate for the way your hearing system behaves at different listening levels. So, the size of your room, or the materials you listen to don't have any influence on this. However, the recording level of the program material has a huge effect. For example, Volume Step 50 results in a very different listening level whether you're watching a movie or listening to Metallica. The important thing with a Loudness function is how loud the sound is - not the volume level. I tuned the factory defaults in the TV using movies, television and music - so it's an average, intentionally weighted towards TV and Movies. However, if you listen exclusively to pop music (which is typically louder than TV or movies), you might find that the factory defaults are a little high. - A Loudness function of some form is built into every B&O TV that I know of. The difference with the V1 and BeoVision 11 is that you have the ability not only to turn off the function in the Sound Mode controls, but also that you have the ability to adjust how aggressive the behaviour is. As far as I know, these are the only consumer products that give consumers this degree of control. John: 2) I've been astonished by the amount of L.F.E the Lab 9's deliver when the effects are there in great strength on a movie sound track (using movie sound mode at factory default, running in 3 channel mode with V1-40 + Lab 9's, at a volume level of 60 and using a Bluray disc via HDMI.) I note from the technical sound guide, that with a Lab 9, and with respect to bass management, low bass is only filtered/panned off to a Lab 5, and not to any other speaker in the B&O portfolio including a Beolab 2 subwoofer. I note also that the low frequency response circa -10db ref midrange for the BeoLab 9 is 28hz, and for the Beolab 2 subwoofer, 25hz. Question: Apart from being likely to be able to play louder, lower and for longer in the case of the Beolab 2 subwoofer, would there be any likely advantage in adding an Beolab 2 subwoofer to my system? I assume from my interpretation of the technical sound guide that it would handle the L.F.E. only, and hence take some of the load off the Beolab 9's, but provided my Beolab 9's are up to the task of handling movie L.F.E. both in performance and reliability/durability terms, I would rather save the funds towards Beolab 3's as intended surrounds, and (please God!) BeoLab 5's later on if at all possible as my main system speakers, and moving the Lab 9's to the surround position. Your interpretation of the Technical Sound Guide is correct. You've noticed that the Bass Management will not remove bass from a BL9 and send it to a BL2. However, you'll also note that a BL2's bass will not be sent to a BL9. This is because, if you average over a "wide" frequency range (albeit restricting yourself to low frequencies) you'll see that they are roughly equally capable. However, since you probably have TWO BeoLab 9's, they share the work, and thus certainly gives you more bass capability than you would have from a single BeoLab 2. The low frequency range limits that you quote there are only true at low listening levels below the ABL thresholds. This number tells more about the sound design of the loudspeaker than its performance. In other words, it tells you a little about how low in frequency we're pushed the tuning when things are quiet, but it doesn't give you any information about how loud the loudspeaker can play bass. I hope that this answers your questions. Cheers -geoff
Thank you so very much for taking the time out to respond - your reply most certainly does answer my questions, and I am extremely grateful and indebted to you for taking the time out of your undoubtedly busy work-life and responsibilities at B&O, to both reply and in such exceedingly helpful detail.
I've been involved in both music and audio since a very young age, and have also been quite 'hands on' with it, having a technical/engineering leaning and some background training, but most certainly respect my own limits of knowledge, especially as a newcomer to B&O, and am accordingly just so very grateful that an highly qualified and knowledgeable engineer such as yourself is prepared to answer what must otherwise seem quite tedious questions - especially from a recovering audiophile who started to get caught up in the audiophile subjective 'foo' that so permeates the industry at a commercial and hobbyist level.
Part of my buying 'into' B&O, has been to purchase an integrated AV system with performance, design, and engineering at the highest levels, and as a user, with a minimal box count, intuitive ergonomics/interface, beautiful design, and with an audio philosophy firmly grounded in the original tenets of HiFi - 'the closest approach to the original sound'.
The other reason for my buying into B&O, was to step away from the mainstream audiophile approach to building an HiFi or AV system, with mixing and matching of components at the retail level, as it oft becomes a very hit and miss approach, with repeated changes of boxes, interconnects etc, to try and get the 'best' sound - and for many audiophiles it appears that the purported 'best' sound is more like an exercise in wine tasting and flavouring, - albeit in a very expensive and seemingly never ending manner, - thus to achieve a sound that mostly it would appear from the wholly subjective comments one reads on forums and in HiFi magazines, that just best pleases me, rather than the closest approach to the original sound - the original tenet of HiFi.
As such, as a classical musician, but one who also appreciates and is interested in HIFi, and someone who regretfully started to get caught up in all the obsessive audiophoolery that goes on with the HiFi hobby in many areas, I am so deeply grateful to find that my two main aims at changing from my present high end separates HiFi/AV system, to B&O, have been met.
The performance, and design etc of the Beolab speakers is there for all to see and hear; but to have your insight into the design process and exceptionally detailed engineering that goes on to not only maximise the performance, but to ensure the durability and reliability of the product was deeply interesting, both technically speaking and as a newcomer to B&O, and I'm indebted to you for posting such helpful and deeply interesting information. I'd also add that it solidifies my faith and commitment to B&O as a customer, but especially as to the integrity of the engineering behind it, and makes me doubly proud to be an owner!
Musically, I find the Beolab 9's stunning, and reminiscent of top of the line headphones in their detail retrieval and naturalness of timbre. I could go on, but you know all this...
When I look back at the years I spent faffing about with separates and passive speakers, - in the pursuit of the 'closest approach to the original sound' - I only wish that I'd come to B&O, and active speakers designed as a total music/AV system by highly qualified, tertiary trained engineers, decades earlier.
We all buy HiFi for different reasons, and I wonder if some of those who buy B&O mainly for it's style and design, realise just how, in comparison with the mix and match separates/passive speakers so called high end audiophie world, what technically advanced, balanced and finished products B&O speakers are; a complete and finished design by some of the best and brightest minds in the business - acoustically and technically.
If I ever make it to Struer for a visit to the factory Geoff, the drinks are on me!
Thank you once again, for your most helpful and deeply insightful comments, and for which I am extremely grateful.
John..
Geoff, would you also recommend leaving Loudness on in a 7-55? As mentioned in another thread, I have been trying out a pair of 5s for the las few weeks and will have for another two weeks. I find I like my current 9s as well as, or better than the 5s. I have always had loudness set of off.
Just switched it to On and will be listening but wondered what you would recommend.
Thanks!
Beolab 28s Beolab 9s Beolab 12-3s Beolab 1s Beolab 6000s 2 pairs Beolab 4000s Beovision 7-55 Beovision 10-40 Beoplay V1 32 inch Beovision Avant 32 inch Beosound 1 (CD player) Beosound 3000 Beosound 5 Core Essence MKII Beoplay M5
Martin, just been reading some of this thread on ABL, you mentioned about turning off ABL on BL5s? Do you, does anyone know if this is possible and if so how. Really fed up with bass by that I mean, the 5s are unforgiving with any master recordings that have been badly or over produced (i.e. bass added because poor studio monitors were used. I've clocked up dozens of notes on which recordings sound absolutely spot on with BL5s and lots more that really are bad (but you wouldn't notice on an inferior system|). Bit ironic that you pay for 5s and they sound poor, not because of the speakers, but because the original master is not truly balanced. This all means that it's pot luck that what you're listening to will sound fantastic when you turn it up. So reduce the thump that 5s give you, I'd like to take the ABL out so I can enjoy more recordings. There is enough real bass in the 5s anyway to not need the ABL. Just want it flat with no bells on? :-) Anyone advise? Suppose I could look on the B&O web site for the manual but I'm wondering if there was another service option / setting known only to dealers or engineers perhaps. Right now they're in OPTION 0 as they're fed via Powerlinks from a BV10 (humm) guess I could drop the bass on the BV10 settings, may help, had forgot that....
Razlaw: Geoff, would you also recommend leaving Loudness on in a 7-55? As mentioned in another thread, I have been trying out a pair of 5s for the las few weeks and will have for another two weeks. I find I like my current 9s as well as, or better than the 5s. I have always had loudness set of off. Just switched it to On and will be listening but wondered what you would recommend.
Hi,
I know that it sounds glib, but my recommendation is to set the loudness to whatever you prefer. If you like the behaviour of the TV with it on, leave it on. If not, turn it off. Just remember that the way to test it is to listen for changes in timbre as you change the volume setting. One way to think of things like loudness (and background noise compensation in automotive systems) is "if you can hear it working, it isn't".
Of course, if you are listening at low levels, then the loudness function is applying a bass boost (regardless of which product you have - some products may also be adding a treble boost). If, at those levels, you find that you have too much bass, then one way to reduce it is to turn loudness off. There are, of course, other ways...
I just came across this thread.
Many thanks to John for posting his question (and to the other contributors).
A post like this makes it worth spending hours (and hours) reading on BeoWorld
By the way - question for John (if he is still following the thread):
"..which I'm using for a two channel 'pure' music mode".
Which source/device are you using to listen to 2-channel music?
A CD-player connected through 'digital out', your (?) BluRay player, the MediaPlayer of the V1, or....?
Greetings Millemissen
There is a tv - and there is a BV
Millemissen: I just came across this thread. Many thanks to John for posting his question (and to the other contributors). A post like this makes it worth spending hours (and hours) reading on BeoWorld By the way - question for John (if he is still following the thread): "..which I'm using for a two channel 'pure' music mode". Which source/device are you using to listen to 2-channel music? A CD-player connected through 'digital out', your (?) BluRay player, the MediaPlayer of the V1, or....? Greetings Millemissen
Hi Millemissen
My system as described previously is the V1-40, flanked by a pair of Beolab 9's - for the time being surround is provided by a lead I sourced from the ever helpful and thoroughly professional Steve at Sounds Heavenly, running from the V1 to my previous TA-DA9000ES Sony amp, which is driving a pair of Tannoy MX2's for surround duties, with the V1 handling all the processing and the levels balanced up with an SPL meter.
For 2 channel music, I'm using my iMac via iTunes with ALAC rips of my CD collection, streaming over an Apple distributed WiFi network, to an Apple TV3 connected to the V1 via HDMI. When listening to music, I use the 'custom' mode in the V1 sound modes, as this is indicated in the manual to be the closest to a 'direct' or 'pure' mode without any influence from AV processing etc. Generally I 'mute' the picture as well, as I find it a little distracting when listening to music, but I can't say if doing so makes any difference to the sound.
For movies, I use a Sony Bluray player, connected via HDMI to the V1, and use the default 'movie' mode for both sound and picture.
In fact, all my settings for the V1, both picture and sound are at factory default. It may be possible to improve upon them, but frankly I am so happy with the picture and sound that I feel no need to tweak and play - which is a huge antidote for me coming from the ever tweaking, never satisfied, audiophile world.
I've had the TV now for 15 months and the speakers for 10 months, and it's still far and away the best performing, and most satisfying ownership experience of a HiFi/AV system that I've ever experienced.
I hate to come across like a B&O fanboy, but I've listened to many so called high end systems over many years, and spent a small fortune on some of the more recognised brands such as Naim, and would never change again having experienced B&O - there's simply nothing else quite like it in terms of it's blend of qualities.
The fact that one can have an online conversation with some of the most talented and highly qualified people in the industry such as Geoff Martin, with his wonderful in-depth explanation of the inner workings of ABL - which is patented and proprietary to B&O - is something that just takes ones pride of ownership to the next level.
Re-reading some of my words I've written here, I may possibly seem over lavish in my thanks and appreciation to Geoff perhaps, but when I look back at the sort of pseudo science, foo and general snake oil that permeates much of the so called high end audiophile scene, and which I found myself and my wallet caught up in, much to my chagrin and regret, the Science and Engineering lead team at B&O, of whom Geoff is a part, is a wonderful relief and antidote to audiophoolery, that I cannot overstate in my experience of the travails of the high end audio scene.
I've just discovered this thread too, and it is well worth reading several times!
The original thread heading about ABL protection gives no real indication of how this useful thread developed: maybe John could go into the edit function and change the heading. Something like 'B&O Adaptive Bass' would have had me reading the thread months ago.
Graham
vikinger: I've just discovered this thread too, and it is well worth reading several times! The original thread heading about ABL protection gives no real indication of how this useful thread developed: maybe John could go into the edit function and change the heading. Something like 'B&O Adaptive Bass' would have had me reading the thread months ago. Graham
Thanks Graham - good idea given the way the topic expanded and that there is so much useful information in there from Geoff Martin in particular; I expanded the heading to greater reflect the consequent discussion that evolved.
HTH