Behringer DCX2496 digital X-over

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#4,422
passive out DCX2496

Pano said:
Tojoko, thanks for the measurements, I am able to open them no problem.
But I don't understand what is going on here. The noise floor in the second measurement show spikes that do not look mains frequency related. Overall distortion is low, but it looks very spiky. Maybe it's a clock problem?

What are you using to get the digital signal to the DCX and what are you using to get the analog signal back into REW?
Click to expand...

Hi Pano
Using digital out from PC, and Line in from PC, it is a build in (OEM) soundcard, I think the spikes were caused by interference, the cable were close to the powersupply of the PC, moved them away, and now it looks less spikye.
would appreciate your comments on the measurements.
Cheers, Tom.
 
#4,423
Pano said:
Yes, that's what I meant. The DCX is meant for pro line level which is a good bit higher than consumer line level. That means that if you are using the analog inputs your signal levels will be low compared to the noise levels. That might be what is causing your ground noise, or at least making it more obvious. Are you going in and out balanced?

Gain structure is important, and can be difficult with the DCX.
Click to expand...

Yes i'm in/out connected in XLR-to-XLR cables
I'll try to see if i got hum and buzz when the Pre-amp is disconnected
 
#4,424
passive out DCX2496

Pano said:
Tojoko, thanks for the measurements, I am able to open them no problem.
But I don't understand what is going on here. The noise floor in the second measurement show spikes that do not look mains frequency related. Overall distortion is low, but it looks very spiky. Maybe it's a clock problem?

What are you using to get the digital signal to the DCX and what are you using to get the analog signal back into REW?
Click to expand...

Here is the less spikey Tommod version....
 

Attachments

#4,425
Not sure I am following the discussion too well, but I took the attachment of post #4411 ("Tommod4") and compared it to my very quick and dirty minimally gussied-up 12-smoothed curve.

There are two curves in the attachment, one looks a tiny bit better than the other. My distortion curve is the one marked "Behrin...". The plot shows the crap-level below the fundamental (which in all Behringer plots is just flat, of course).

Both not audibly different than my quick and dirty test since the THD is in the residual test noise level and well below most homes and so a waste of time, at least judging from this one datum.

I am using a coax S/PDIF input A digital input (which isn't quite an AES signal and so to Behringer's credit that it seems to use it just fine anyway). So there's still room for people to argue about all the crap introduced when using the analog input A.

Have I previously mentioned I bought this Behringer about a dozen years ago. Basic model hasn't changed except for LE budget omissions.

B.
 

Attachments

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#4,427
Tojoko, the Tommod 5 measurement looks good, distortion is generally falling as frequency goes up, not too much noise. I don't believe any of that would ever be audible.

Ben, your REW file would not open, says it's not MDAT format.
 
#4,429
passive out DCX2496

Hi Pano
Thanks, only thing that is a bit weird is the noisefloor, distinct 50 hz, our mainvoltage frequency, but distortion is low, only at 25 hz a bit more, but that will not be heard, I think...
Cheers, Tom aka Tojoko.
Same here could not open Ben's file.
 
#4,431
Pano said:
Tojoko, the Tommod 5 measurement looks good, distortion is generally falling as frequency goes up, not too much noise. I don't believe any of that would ever be audible.

Ben, your REW file would not open, says it's not MDAT format.
Click to expand...

Puzzling. The attachment from DIYaudio unzipped and worked for my Mac OSX.

Earlier a REW upload attempt failed which I assumed was due to large size or something. So I uploaded a zip condensed version.

Glad to cooperate when I learn how best to help.

B.
 
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#4,435
tojoko said:
Hi
Can someone put a zipped REW file of a stock DCX2496 in thiss forum, I only got 5 modded DCX2496 🙂, would like to see how stock measures....
Tojoko.
Click to expand...
Pano is right, the unit is stock although quite old. But I used a digital signal to Input A (as many people will be doing) and therefore skipped past the DCX's input ADC conversion. Some people (not me) think that the input ADC and the output DAC are weak links inside the DCX, so maybe not the full-monty stock as some use theirs.

My posted test results are done with my "vintage" equipment in the loop and would have looked even better had I used a louder input. Testing with a louder signal raises the signal further out of the noise when testing but, up to clipping point should not increase relative distortion.

Also, I just sat down and ran REW and just posted the first curve that I got.

Anybody with REW and some cables can test their unit. I been pestering this thread to show test results for many years. Looks like it's happening now.

B.
 
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#4,437
Hello there,
I've one weird behavior which i'm not able to correct.
I've setup my DCX2496 for 3 speakers driven in 2 ways so in LHLHLH mode (A:left, B:center, C:right)
A goes to 1 & 2, B to 3 & 4, C to 5 & 6

when i tred to mute each channels one by one i discovered something strange only happening on my Right & Left Speakers, I got my High sound only available with channel 1 is unmuted but on both speakers, and when I mute channel 1, all High are muted...even channel 5.
which is not normal as all my channels should be independents.
here is the link of the config i've extracted from my DCX if someone is able to investigate what happens.
 
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