DCX2496 into Quest 3004

[Drizt]

Originally Posted by AndrewT

if you input a digital signal of a modern highly compressed CD into the DCX much of the signal will be at +21.9dBu for much of the time.
If all the EQ is flat and all the filters are flat then the output of a "modern CD" will be +21.9dBu.

If you add any high Q filtering or +EQ then the internal signal will be above +22dBu. The avoid this you must reduce the DCX gain until the maximum signal in every channel is <+22dBu. This will give you regular peak signals that are 13.8Vpk.
This will overload most domestic equipment.
You must add passive volume control AFTER the DCX.

If you input an analogue signal extracted from a "modern CD" then you must try to maintain maximum unclipped signals through the DCX.
If you reduce the analogue input using the DCX -15dB gain control you will ruin the signal to noise ratio at the output.
You will also ruin the signal to distortion ratio at the output.

Thank you again. All very helpful information. Ill be using analogue inputs, and using the MX882 to up the levels to what the DCX desires.

If I wasn't planning on 'Summing' some inputs on the MX882 then I could have just used the MX882 to both up the levels on the way in to the DCX and then down the levels on the way out of the DCX. But by 'Summing' in the MX882, if I did try to use it both pre and post DCX then I would create a feedback loop.

Hmmm, perhaps I should find a really cheap device that can do Summing..... Or just buy two MX882's, but that would seem a waste.

[Drizt]

Actually, perhaps I can just use the one MX882.

Each input can be set to split or mix mode. I thought the whole unit was either in split more or mix mode, but seems it can be done on an individual channel basis.

So I could do...

Main inputs, are the LPF (40Hz and below) output from my active main speakers.
Input 1 could be the LFE channel which gets mixed into both the L & R main outputs.
Set the main output levels appropriately for the DCX.

This could then be feed into the DCX .
The output from the DCX could then be feed back into the MX882 on channels 3 & 4.
Set those channels to 'split' mode (so that they don't get summed to the main outputs and create a feedback loop).
Set the output levels to what is appropriate for the inputs of the Quest 3004.

Work out the appropriate gain or sensitivity on the Quest.

I 'THINK' thats how it could work.

Originally Posted by Drizt

If I wasn't planning on 'Summing' some inputs on the MX882 then I could have just used the MX882 to both up the levels on the way in to the DCX and then down the levels on the way out of the DCX. But by 'Summing' in the MX882, if I did try to use it both pre and post DCX then I would create a feedback loop.

Hmmm, perhaps I should find a really cheap device that can do Summing..... Or just buy two MX882's, but that would seem a waste.

[Drizt]

Originally Posted by Drizt

snip...

I was wrong again... this is getting repetitive, me making mistakes that is

I can't use the 'sum / mix' functionality if I want to do level matching on the outputs of the DCX as it would create a feedback loop. I 'think' I was right the first time.

I 'think' I have to scrap the idea of combining the Low Passed (40Hz and below) from the L & R mains with the Home Theatre LFE channel.

Summary:
Input 1). could be a copy of the LFE (use a splitter cable from my Integra DHC-9.9), which I put in 'mix' mode, adjust gain for DCX input, and output straight out of Output 1.

Input 2). could be a copy of the LFE (use a splitter cable from my Integra DHC-9.9), which I put in 'mix' mode, adjust gain for DCX input, and output straight out of Output 2.

Input 3). this would be the L output from the DCX. Here we would lower the voltage to the whatever is needed by the Quest 3004 for the Left channel input.

Input 4). this would be the R output from the DCX. Here we would lower the voltage to the whatever is needed by the Quest 3004 for the Right channel input.

Damn, I hope I have it right this time.. talk about a merri-go-round in my head :P