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Old 16th July 2004, 11:12 AM   #111
nowater is offline nowater  Australia
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OK, here goes. (I hope the other posters on this thread can chip in with their conclusions, too.)

It mostly looks like good news. The output voltages from the DCX at 0dB are 10x larger than at -20dB, so there is no obvious compression indicating clipping.

The 9.26Vrms output voltage from the DCX at 0dB is +21.6dBu, very close to the spec sheet's +22dBu. Good. None of this indicates any clipping.

In step 1 you said the clipping disappears if the DCX is removed and you listen with DEQ only. This suggests the input to the DEQ and its analog output are not to blame. I thought maybe its the DEQ digital output, but in step 4/5 you got audible clipping with DEQ analog output to DCX, so it's not the DEQ digital output either.

Step 2 simply showed the DEQ was correctly "zeroed" internally. (I just wanted to make sure.)

In step 3 I am not sure why, if the DEQ output voltages are 12.9dB (voltage ratio of 4.4) lower with analog input, the input levels are not 12.9dB lower. They only measure 3.5dB lower. But I cannot connect this discrepancy to your problem. Help, anyone?

Conclusion: I'm not sure! Given that step 1 absolved the DEQ, and step 4/5 shows uncompressed outputs from the DCX even when audibly misbehaving, I think your DCX may have a fault. And it's not in the input circuit, because it happens with both analog and digital input.

You haven't tried uploading the DCX software from their website? It is possible to get it wrong when doing this.

Comments from any other posters? That's about it from me.
Grant
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Old 17th July 2004, 02:52 AM   #112
Vadim is offline Vadim  Canada
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I have been using both the DEQ and the DCX for a while now. I use digital connection between them. For the past month or so I had my trusty scope plugged into both units in the effort to make some sense out of the many options available in the software of both the DCX and the DEQ. I use signal generator as an analog source for test purposes and I can readily observe the levels of the signals on the scope. Well, I must say that the specifications as given in the manual for both units are dead on.

I also, like AR2, observed the clipping as displayed on the input indicators of the DEQ and the DCX when the optical SPDI/F signal from a common CD Player is used as an input to the DEQ. However, that does not result in the clipping of the ANALOG output signal on EITHER the DEQ or the DCX as observed on the scope or heard through my speakers.

The reason for it has already been addressed by Jan Didden. The digital signal coming through the SPDI/F can easily has the maximum value of all 1s or be very close to it, which will correspond to the 0 dB level. Many CDs are actually recorded that way. The input indicators on both the DCX and the DEQ will light up RED at about 1-2 dB below the 0 dB level. Does it mean the output is clipping? No. In any event it is not the fault of the Behringer boxes.
Another point to keep in mind here is that the internal limiter of the DEQ is ALWAYS on and cannot be defeated; - it should help with any overdriven analog input. In any event, it seems to me that there might be a problem with AR2s DCX box.

I recommend that the limiters on the DCX be turned ON and set to 0 dB threshold. Can you still hear clipping?

Also, even if the input indicators go RED, I am sure that the output indicators on the DCX do not go RED or, at the very least, they should not go RED. If they do, that would indicate a problem to me.

You see, the input indicators average the input signal and use that value to see the level of the input signal. The output indicators are band-limited and, as such, their absolute signal level is expected to be lower then the averaged level of the input signal. The output clipping will only occur if the input signal level is actually above the specified +22 dBu. I am not talking about the discrete sine waves here. They will in fact clip the output if the input is set to +22 dBu. However, with you typical music material, the average signal level will have to be higher then the 22 dBu for the output indicators to show clipping, or so this has been my experience.

Here is what I did recently; - I input a boosted analog signal from my CD Player into the DCX. I used a Bryston pre-amp to boost the signal to about 12 Volt peak and input that into the DCX. I observed a very occasional RED indicator from the output LEDs, while the input indicators were pretty much RED all the time. With limiters set to ON on the DCX, no clipping was heard from the speakers, no seen on the scope.

Well, I hope it helps.
Vadim
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Old 17th July 2004, 08:40 AM   #113
AR2 is offline AR2  United States
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I think that we are coming to good conclusion.
I agree with all you guys explained, especially with the last post from Vadim. I do think that maybe my DCX is damaged.
I have DEQ almost a year and never had this kind of a problems. Yes it is correct that majority of CDs are recorded so they reach -0dB and it is correct that that never produces any clipping down the line.
I purchased DCX about twoo weeks ago, and I noticed this problem from very begining. I updated the firmware to the latest version without any problems, hoping to solve the problem.
It is a weird clipping that goes on. DCX's analog output never reaches red zone, far from it. Even with almost maximum attenuation in front of the amps, heavy distorsion sound goes to the speaker, which obviously pointing problem to the DCX. With analog in there is no problem. With digital signal attenuated at input to about -7dB usually solves the problem.
I did tried limiters at about -6dB setting and they are doing fine job, the only problem is that they are in use almost all the time, which kills the dynamics a lot. In that case I was better of just lowering the volume.
I think I will take my unit to exchange for another one. I will let you know what is the verdict.
Thank you all very much
AR2
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Old 17th July 2004, 10:56 AM   #114
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Don't know if this should be in a new thread, but has anybody considered using a pc sound card to do the A-D conversion ?

Reason being you can use the vol. control on the pc to digitally attenuate, acting like a digital pre.

Could also use remote control with this:

http://www.girder.nl/index.php

I'm considering this for my turntable.

Cheers,

Rob
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Old 17th July 2004, 09:46 PM   #115
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There is a lot of good educational reading here.

I still only have my DCX hooked up to the 5x subs, fed digital via the DEQ as others have, so I haven't intergrated it with the mains yet.

I emailed our local Behringer office, and asked if I could beg, borrow or steal a schematic of the DCX, so I am hoping for an answer early next week.

Don't go holding your breath, as others have said, Behringer do not make these available, but hey I figured nothing ventured nothing gained...
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Old 23rd January 2006, 08:02 PM   #116
youmax is offline youmax  Argentina
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Hi, someone have a Bodzio software called soundeasy ?????, where can download?, work for DCX2496 ?. whait for comments, best regards.
Ariel from Argentina.
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Old 31st January 2007, 05:15 PM   #117
oettle is offline oettle  Germany
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Hi to all DCX2496 owners,

Is there anybody who is interested in the Oehlbach mod:

http://freerider.dyndns.org/anlage/B...ut-Stage-E.htm

I bought 4 of them, 2 for a friend of mine and 2 for me. Due to a misunderstanding my friend doesnít want to have the mods any more. So there are two left. Iím pretty happy with the mod. You can hear noticeably more details.
The price for one PCB plus all components is 75 Euro. Assembled and tested you can have one mod for 85 Euro plus shipping costs.

Please send me an Email when you are interested.
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Old 31st January 2007, 05:57 PM   #118
DougL is offline DougL  United States
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Quote:
Hi, someone have a Bodzio software called soundeasy ?????, where can download?, work for DCX2496 ?. whait for comments, best regards.
Soundeasy is a comercial speaker design software package, similar to LpCad or Speaker Workshop.
You can buy a copy @ Parts Express for example.Soundeasy @ Parts express
I have Soundeasy. While its capable of programing the DCX2496, the capability is rather limited. Basically, you build the crossover in Soundeasy using active filter elements that the DCX2496 supports, then download it. Its easier to program the DCX through the windows interface.
Soundeasy will also simulate passive crossovers, using a multi-channel sound card. I have never tried this, but it looks interesting and is my backup if the DCX2496 stops working.

Hope this helps

Doug
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