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Hey everyone, this is my first time posting although I am an avid reader of the forum.
I recently made the jump and bought a pair of BeoLab 18s (only speakers that satisfied both demands of my wife (design) and mine (sound) :-))
I now have a question of how to hook them to an Airport Express (I read their DAC and digital output is really, really good).
The BeoLab 18s have Powerlink (RJ45), RCA and Toslink inputs. In theory, I can connect to any type from the AE as I can use a mini-jack to Powerlink, mini-jack to RCA or Toslink-Toslink cables - the question is, what should I use?!?
Many thanks for your help!!
Hi and welcome to Beoworld - and congrats to your new speakers.
You most certainly will get some different answers on that subject.
Personally I would use neither!
But I would encourage you to have a look at the BS Essence.
This will certainly give you a better DAC and more possibilities - e.g. a better volumen control...
If you can wait, you should look out for the coming 2. Generation BS Essence,
Maybe (?) that will have WiSA, which means, that you can hook the speakers up wirelessly to it.
In the meantime use either of the possibilities, you noted.
Enjoy your speakers - sound- and design-wise.
MM
There is a tv - and there is a BV
Thanks so much for the quick reply!!
I also thought of the Essence or the Transmitter 1, but i think we pretty much maxed our budget with the speakers for the moment ;-)
Two quick follow up questions:a) If I use Toslink, I presume the BeoLab 18 uses a built in DAC, is this as good or better than the AE DAC?b) When using mini-jack to PL, I have one cable connecting both speakers. If I use Toslink, do I then hook up the Toslink to one of the speakers and then connect the two speakers together via PL?
a) the DAC of the BL18 is 'miles above' that of the AE (which is normally concidered rather poor).
Note: If you use the dig. out of the AE, you don't use the DAC in the AE, since there is no convertion done there.
The digital to analog convertion will be done in the BL18?
b) reading the User Guide for the BL18 should answer that question.
mk2012: Thanks so much for the quick reply!! I also thought of the Essence or the Transmitter 1, but i think we pretty much maxed our budget with the speakers for the moment ;-) Two quick follow up questions:a) If I use Toslink, I presume the BeoLab 18 uses a built in DAC, is this as good or better than the AE DAC?b) When using mini-jack to PL, I have one cable connecting both speakers. If I use Toslink, do I then hook up the Toslink to one of the speakers and then connect the two speakers together via PL?
When using toslink, acording to the manual, you also daisy-chain the 2 BL18's. One toslink from AE to BL18-1, and the toslink from 18-1 to 18-2..
The AE is using 16 bit cd quality DAC, and it seems that the BL18 DAC is better.
BL18 DAC : Sample rate 32k, 44.1k, 48k, 96k / PCM16-24 bit
So I would use toslink if not it causes problems with the wires, toslink cables cannot be bend the same as PL cables.. Even though the DAC was the same bits in AE and BL18, I would still use toslink based on th fact that I would say that the DAC would/should be better in such an expensive speaker, than the AE
/Weebyx
Weebyx: mk2012: Thanks so much for the quick reply!! I also thought of the Essence or the Transmitter 1, but i think we pretty much maxed our budget with the speakers for the moment ;-) Two quick follow up questions:a) If I use Toslink, I presume the BeoLab 18 uses a built in DAC, is this as good or better than the AE DAC?b) When using mini-jack to PL, I have one cable connecting both speakers. If I use Toslink, do I then hook up the Toslink to one of the speakers and then connect the two speakers together via PL? When using toslink, acording to the manual, you also daisy-chain the 2 BL18's. One toslink from AE to BL18-1, and the toslink from 18-1 to 18-2.. The AE is using 16 bit cd quality DAC, and it seems that the BL18 DAC is better. BL18 DAC : Sample rate 32k, 44.1k, 48k, 96k / PCM16-24 bit So I would use toslink if not it causes problems with the wires, toslink cables cannot be bend the same as PL cables.. Even though the DAC was the same bits in AE and BL18, I would still use toslink based on th fact that I would say that the DAC would/should be better in such an expensive speaker, than the AE /Weebyx
First of all - the quality of a DAC is not just dependent on bit and sample rates - it takes a lot to make a good digital to analog convertion.
The DAC in a modern BeoLab is not just a DAC, it is a DSP solution for audio processing - what B&O call an 'audio engine'.
But - you don't have to worry about bit and sample rates at all.
Airplay streaming to the AE is always done in the 16/44.1 standart - that is part of the AirPlay protocol.
So when you connect them via Toslink, how do you control the volume on them? Let's say I stream music via Airplay to the AE and the 18s are hooked up via Toslink, will the volume control on my iphone work? This seems like a stupid question but Steve from SoundsHeavenly said if I use Toslink it will also go to max volume...
I really doubt that there is a DAC into the BL18 since all signals have to pass DSP.After processing the digital sound signal is converted to PWM and then brought into the amps.So there is no digital to analog conversion on the signal side.
I think there is just an ADC for the PL part...Quality should be best when using toslink.As far as I know AE optical out is volume controlled, too.
BR,BeoMotion.
BeoMotion: I really doubt that there is a DAC into the BL18 since all signals have to pass DSP.After processing the digital sound signal is converted to PWM and then brought into the amps.So there is no digital to analog conversion on the signal side. BR,BeoMotion.
If there is no digital to analog conversion, you can't hear anything.
Whether the conversion is part of a 'DSP solution' or is going on in a 'chip-solution DAC' does not matter.
There has to be a digital to analog conversion somewhere.
N.B. How this exactly is done/what exacly is going on in the modern BeoLabs, those who know it (and made it) won't tell us. (I did ask!).
P.S. I guess you meant 'to PCM' (which is a digital format)?
Well, of course there is a analog signal at the end.
But as I've written the signal side is completely digital. There will be an amplified analog signal behind the amp (h-bridges) + low-pass filter combo.All class d-amps are fed with a PWM (not PCM) signal which is digital.
A common signal path for DSP + class-D amp would look something like this:
Analog in -> ADC -> int. dig. audio bus 1 (e.g. I2S is common) -> DSP -> int. dig. audio bus 2 -> PWM generator -> AMP -> low-pass filter -> speaker
There are also DSPs with integrated PWM generator...An external digital input (like opt. s/pdif on the BL18) would either be multiplexed behind the ADC or directly fed into the DSP (if it offers more then one input).
Millemissen:N.B. How this exactly is done, those who know it (and made it) won't tell us. (I did ask!).
Hi,
There are different reasons to choose the different options here. Let's start by looking at the signal path...
Assuming, for example, that you're going from an iDevice (or iTunes on a Mac) to an Airport Express to the BeoLab 18's:
Option 1: analogue cable from AE to BL18's. (stereo minijack to two RCA's)
This means that the signal is converted to analogue at the AE's DAC, then converted back to digital at the BL18 inputs. This is necessary, since the BL18's filtering is done in the digital domain using a DSP. The individual signals for each driver in the BL18's are converted back to analogue using the internal DAC's (one per driver) and analogue is fed to the inputs of the individual Class-D amplifiers. I believe (although I'm not sure) that the gain that is applied to the signal as a result of the volume control happens in the AE (digitally, of course).
Option 2: TOSLINK from the AE to one BL18. Daisy-Chained TOSLINK to the second BL18.
The only real difference between this and the previous signal path is that the AE DAC and the BL18 ADC are taken out of the path, since there is no conversion to analogue (and back to digital) between the two devices. I believe (although I'm not sure) that the gain that is applied to the signal as a result of the volume control happens in the AE (digitally, of course).
So, except for the extra DAC/ADC components in the path, the two chains are effectively identical. The BL18 is set to "full volume" in both cases (a better way of saying this is that their sensitivity does not change), since the volume command from the iDevice is applied before the signal arrives at the BL18 input.
Now we have to ask some questions:
1. Is the DAC+ADC addition to the signal path the "weakest link in the chain?" My experience with my Mac's minijack output compared to the TOSLINK output, when connected to the BL17's, 18's and 20's is that the overall noise floor is lower with the TOSLINK. This makes sense, since the DAC of the Mac is relatively noisy (for example, it can be heard when it's gated on and off when listening with headphones). Whether the DAC of the AE is better (or worse) than my Mac (a 17" MacBookPro from 2011 - I cannot comment about other models...) I don't know. I also don't know whether there are differences in the noise floor of the DAC's of the different generations of AE's.
2. What is the behaviour of the volume control on the iDevice? For example, if the first volume step (the lowest one above "mute") is too loud, then there is not much you can do about it on TOSLINK. However, if you're using the analogue path, you can pad (lower the level of) the signal between the AE DAC and the BL18 ADC.
3. If you use the analogue path between the AE and the BL18's. AND if you have padded the level to reduce the maximum volume. AND if you listen to music with significant dynamic rage: Does your music, at low volumes, have enough level to automatically turn on the BL18's? This is a "corner case" but it might be significant if you like classical music and you've got a 20 dB pad on the cable, for example...
4. Is the output of the AE TOSLINK output properly dithered? If not, then at low volume settings, with quiet music (either quiet passages or low mastering levels) , you'll hear a distortion like a crackling noise that modulates with the signal. If it is dithered properly, then you might hear a noise floor (depending on whether the dither is at 16 bits or 24 bits (or something else). I don't know whether the AE volume control is dithering correctly these days. I know that it did not 6 or 7 years ago when I bought my first AE - but that's many generations ago - I have not tested the new devices.
5. If you're using a Mac as a source and you are using the TOSLINK output, you may have some initial issues with signal sounds (like "you've got mail") being surprisingly loud because they have a volume control that is independent of the iTunes volume. There are ways around this - and I don't know whether the same problem occurs with an AE - I've only experienced it with the TOSLINK output of my Mac when I first started testing the BL18's and BL17's.
That's enough questions... However, as you can see, the question is not whether the DAC in the AE is better or worse than the DAC's in the BL18 - since the DAC's in the 18 are used whether you go into the TOSLINK or the analogue input. The big questions are really
- can you hear the added noise of the analogue addition to the signal path?
- is the AE signal dithered properly at the TOSLINK output? (listen for distortion in quiet music at low volume levels to find out)
- does the iDevice's volume knob behave "better" (more to your tastes) for one cable than the other (I expect that there is no difference here - unless you've padded the analogue signal, of course)
Hope this doesn't make things more confusing...
If it helps, I can say that, when I did the sound design of the BL17, BL18 and BL20, I just used the TOSLINK output of my MacBookPro connected to the loudspeakers. However, I was using my own custom-built volume knob with 24-bit dithering in the tuning software that I made on the Mac - so I don't know about iTunes's behaviour with the same signal path.
Cheers
-geoff
Geoff Martin:The individual signals for each driver in the BL18's are converted back to analogue using the internal DAC's (one per driver) and analogue is fed to the inputs of the individual Class-D amplifiers.
Why? Why using an analogue signal to feed a PWM comparator? Wouldn't it be better to keep it digital?
BeoMotion: Why? Why using an analogue signal to feed a PWM comparator? Wouldn't it be better to keep it digital?
Not necessarily - it depends on the requirements of the particular product and the integration of its various components. In the case of the BeoPlay A8, we use a PCM to PWM conversion to connect the inputs of the class D amps to the outputs from the DSP. In the case of other products, like the BL18, we use DAC's feeding the analogue inputs of the class D amps. So, that particular part of the signal path is a decision that's made on a product-by-product basis.
- geoff
BeoMotion:Why? Why using an analogue signal to feed a PWM comparator? Wouldn't it be better to keep it digital? BR, BeoMotion.
Hi. I have the same problem with my Beolab 18. About every tree days there is a cracking sound from the speaker connected to the other speaker with Toslink optical. After rebooting the speakers all is fine again. I use optical (Toslink) out on Sonos Connect as input to my BL18.
Who told you, that it's a software issue in BL18, and did you solve the problem?