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Greatings all.
Have bought the Beolab 5 FE an in the process of setting it up in my non-B&O system.
I have had the BL5s running with Sonos and SPDIF. Now use a NAD M51 dac as a hub for the Sonos and a CD player, using the RCA line in option. According to stereophile.com the output mode for the M51 RCA is 2.375 V (http://www.stereophile.com/content/nad-m51-direct-digital-da-converter-measurements#bvS6jwS0ryWJ5y4g.97). That is the number Im looking for when deciding which level to set the BL5s on, right?
(See Geoff Martins post at http://archivedforum2.beoworld.org/forums/p/11900/103849.aspx#103849 "Note, however, that if your goal is to optimise your BeoLab 5 input for a line signal that is higher-than-normal, then you can change the maximum allowable input voltage of the RCA Line input from 2.0 V rms (the default) to 4.0 V rms.")
So the M51 has a RCA line voltage higher than 2, and I should set the BL5 to option 2 (2V - 4V), if all of the above is right..
But... whats the deal? Are there any risks in *not* setting the correct option? Are there flaws to the sound? Will gain be affected?
Just asking hehe :)
(next up in my system is a tube pream, unknown RCA line out level - so Id better get this right...)
Regards
Hmm no answers - sorry if somehow the question is stupid or unclear. Im not good at this :)
I will try a bump for good luck.
just guessing:- Set Beolab 5 to max. 2V input: Distorted signal may occur if you feed them with >2V input signal- Selt Beolab 5 to 2-4V input: Works without problems and maybe maximum volume will be lower than expected which shouldn't be a problem on Beolab 5.
I've tried diferent settings on my setup and the only difference I could tell was a little gain variation, probably because my preamp is limited to the 2V range.
Maybe a more pronunced effect will show up if you use a 2-4V signal while the speakers are set to 2V. I wouldn't say that you get a better or worse sonic response (more bright, transparent or anything like that), but you will avoid your signal from being clipped and the entire system will work with a higher signal-noise ratio.
Makes sense?
A while ago Geoff Martin had an article on his blog called:
'Signal levels and Dynamic Range'
Maybe you'd find some hints there:
http://www.tonmeister.ca/wordpress/2017/02/13/signal-levels-and-dynamic-range/
Or, why not just send him a PM - he is a member here.
MM
There is a tv - and there is a BV
Thx guys, good answers I think, all revolving around signal/noise and clipping. The Geoff Martin link made things clear(er), also with some good practical advice that I had forgotton all about:
Quote:
"The first one is to try to align all your maximum levels as much as possible. So, as in the last example above, if your source device has a maximum output of 2.0 V RMS, set the input sensitivity of your next device to “expect” 2.0 V RMS maximum. This will make the tops of the red rectangles all align, and the dynamic range will be defined by the worst link in the chain instead of the way the devices are connected.
The second rule of thumb is to put as much gain as possible at the beginning of the chain. This is particularly true if you’re working in a recording studio. This is because every piece of gear contributes noise to the audio signal. If you put all the gain at the end of the chain, then you are making the signal louder, but you’re also making all of the noise from all of the gear “upstream” louder as well. If you put all the gain at the beginning of the chain, then you might wind up in a situation where you have to turn DOWN the signal through the chain, those reducing your signal to the correct level, and bringing the noise floor down with it. "
What is left is basically a bit of fright of what might happen if my tube pre exceeds the 4 V by a large margin. I might PM Geoff yes..
This is a fairly complex topic, you're talking about digital audio > preamp analogue line level > analogue input op-amp on BL5 > BL5 ADC .. etc.
There's a fairly common reference of -18dBfs = 0.775vRMS however it is simply one reference. Though in all cases clipping any op-amp on the chain sounds like crap, worse is digital clipping. Terribly mastered music tries so hard to be compressed / limited just below this but that's another conversation.
Now the complex bit is that for some reason flashy consumer audio stuff tend to bump the output level to seem 'better'. It's not totally uncommon to find 2.5vRMS+ on 'boutique' preamps which probably explains why b&o has a provision to ensure proper gain staging.
I can only assume using higher levels gets slightly better SNR.. however that's non issue in professional studio using balanced connections.