Beolab 5 and Beolab 3 with non-B&O Surround Processor

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adrianb (archived)
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Posted May 29, 2009 at 20:18 GMT
#1879087

Hello all

What is the best way to use Beolab 5 front speakers with Beolab 3 rear speakers with a non-B&O Surround Processor?

If we remember that:

Beolab 5 wants fixed 2V RMS line input (volume controlled on speaker).
Beolab 3 wants a variable 2V RMS line input (volume controlled from source).

If using a Beosystem 3 I assume that the Powerlink (or other voodoo) over-rides the Beolab 5 internal volume changes or sets it to a "reference" level of some sort so that it effectively meshes with the Beolab 3.

In theory with a non-B&O surround processor (assuming a maximum out of 2V RMS), I could connect the line outputs to each speaker (BL5 and BL3). Set the non-B&O surround processor to reference (ie: 0dB attenuation), send a test tone to the rear speaker and then adjust the Beolab 5 volume to match the rear speaker from the same tone. I could then store this setting for the BL5 so when the speaker is turned on it starts at this level ready to go for surround applications. Volume changes on the non-B&O surround processor would then change the volume of all speakers equally.

For stereo listening (from SPDIF/coax) I'd need to remember to turn down BL5 before playing to avoid a heart-attack!

Is this the best solution? Is there a better way (without Beosystem 3)? Anyone currently doing this or similar?

Kind regards Adrian

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soundproof (archived)
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Posted May 30, 2009 at 01:35 GMT
#1879088

I have BL5 and BL3 with a non-B&O processor.

All are connected to the processor through LINE IN. Use the surround set-up test tone in the processor to set the same level on each speaker. This gives you a working reference for the rear channels, as well as a volume level for surround. But as you say, s/pdif plays much louder than the line in.

Either try to match that by increasing the analog output from the source (the s/pdif is usually at one level), or do what I did. Once I had my reference level for the speakers, I just reduced the volume of the BL5s by 9 dB (nine ticks of the volume control) before storing the BL5 volume.

That's a good starting level for my s/pdif, which is what I listen to most of the time. When I want to listen to a movie in surround, I just give the BL5s nine quick ticks up.

9dB is the difference I have set here, you may find that the processor you choose has a smaller difference between analog and s/pdif.

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adrianb (archived)
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Posted May 30, 2009 at 02:37 GMT
#1879089

Thanks again for your helpful advice Soundproof (we've got to stop meeting like this!).

Do you know what the RMS output of your processor is?

I'm concerned connecting a 5V RMS or 20V RMS unit will be more difficult or am I just fretting over nothing?

I'm OK with hi-fi... but BEO-land is another (good!) planet! :)

Kind regards
Adrian

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soundproof (archived)
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Posted May 30, 2009 at 04:17 GMT
#1879090

B&O are very specific about ≤ 2V RMS, and the need for an attentuator if you have higher values.

My processor has 2.3V RMS, measured, on the L/R LINE OUTS, and I didn't bother with an attentuator. But if you're well in excess of that, it's not worth it to take any chances, I think.

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