Newbie with some q's, DCX2496, setting up...

[fackamato]

Hi,

I'm trying to set up my future stereo in theory here. What I have (in theory) is an EP2500, a DCX2496, a stereo amplifier (with pre out and main in), two DIY subwoofers.

1) Can I use REW with the DCX2496? (I think I read somewhere that it has a microphone input?)

2) If I can't use REW, can I in some other way use the DCX2496 to measure room response, and export it to a computer?

3) I want to "equalize/correct" my two mains and two subwoofers. Is this possible, for example like this:



Is this possible, like in the "diagram" above? I was thinking a highpass filter on the mains, somewhere around 40Hz, or even 50Hz perhaps, then a lowpass filter for the subs, at 60Hz or so. It depends on the room of course, and measurements...

4) How would I connect everything? I would run XLR between DCX2496 and EP2500, but what about the integrated amp and the DCX2496? Are there XLR<->RCA cables, if there are, would they be a problem? (gain or otherwise?)


I'm sure I'll think of more questions later!

[brucek]

1) Can I use REW with the DCX2496? (I think I read somewhere that it has a microphone input?).
Yes, but you have to enter the filters by hand (no big deal) as REW doesn't have a selection for the DCX2496, but the filters for the FBQ will be fine.

2) If I can't use REW, can I in some other way use the DCX2496 to measure room response, and export it to a computer?
I would use the REW RTA feature.

3) I want to "equalize/correct" my two mains and two subwoofers. Is this possible, for example like this:
Yes.

4) How would I connect everything? I would run XLR between DCX2496 and EP2500, but what about the integrated amp and the DCX2496? Are there XLR<->RCA cables, if there are, would they be a problem? (gain or otherwise?)
The balanced inputs/outputs can be used in the unbalanced mode. No problem.

brucek

[fackamato]

Thanks for the swift reply!

Just to clarify, when I measure the room with DCX2496, is there a way to export the response into RTA? Or is that what you meant by "manually entering filters"?

(are they exportable at all, DCX2496 > PC?)

The REW RTA feature.. that means hooking up a microphone to my PC, right? With loop cables and whatnot... or can the DCX2496 do this somehow?

[brucek]

when I measure the room with DCX2496, is there a way to export the response into RTA? Or is that what you meant by "manually entering filters"?

No on both questions. I don't use a DCX2496 myself, but from reading the manual, I know it has an Auto feature that sets up the delays to aid in smoothing cancellations between speakers. Once that's set, then you simply use REW to measure your sub and then manually enter the filter recommendations into the parametric filters of the DCX2496.

The REW RTA feature.. that means hooking up a microphone to my PC, right? With loop cables and whatnot... or can the DCX2496 do this somehow?

REW requires a microphone for all its measurements, including the RTA feature. The DCX has an AUTO feature that you can also use (that requires a mic).

I highly recommend reading the references I mentioned in my first post.

brucek

[hddummy]

The only thing you may also want to consider is a signal level converter. Standard home electronics output audio in -10dBu (1.25vrms) and the DCX2496 expects a level of +4dBu (21vrms). You can use an Art Cleanbox or a Samson S-convert Box. The DCX will work fine without it, but if I remember reading right, it will only use an equivalent of 16bit instead of 24bit.

[brucek]

I believe the DCX provides input gain control from -15dB to +15dB, unlike the FBQ and BFD that use an operating level switch.......

brucek

[hddummy]

it does, but that is post Analog-Digital Conversion, so it doesn't affect the bit usage of the input signal at all. Again, this is only splitting hairs unless you really care about taking advantage of the full 24bit processing.

[fackamato]

hddummy wrote:

it does, but that is post Analog-Digital Conversion, so it doesn't affect the bit usage of the input signal at all. Again, this is only splitting hairs unless you really care about taking advantage of the full 24bit processing.

Good to know. Since the DCX will be processing all my speakers, I guess this shouldn't be a problem. I would just have to turn the volume knob on the amp higher, to give the DCX a higher voltage on the rca inputs? (thus keeping 24-bitness )

[Wayne A. Pflughaupt]

hddummy wrote:

The only thing you may also want to consider is a signal level converter. Standard home electronics output audio in -10dBu (1.25vrms) and the DCX2496 expects a level of +4dBu (21vrms). You can use an Art Cleanbox or a Samson S-convert Box. The DCX will work fine without it, but if I remember reading right, it will only use an equivalent of 16bit instead of 24bit.

If the Art or Samson add any noise (and I suspect they do) that'll pretty much blow out any "benefit" of going from 16 bit to 24. Not to mention, 16 bit = a dynamic range of nearly 100 dB, which is probably as good or better than most integrated amps...

Regards,
Wayne

[bjs]

I have the DCX driving A500 power amps in balanced mode from a Pioneer 816 receiver and it works fine.

Yes, the input gain on the DCX is digital and AFTER the ADC. However the input voltages required are much lower than posted by hddummy above and readily achieved by most consumer receivers (I think). Certainly my el cheapo Pioneer receiver has no problems driving the pro-level inputs to full volume.

Actually I have mixed pro and consumer amplifiers and they play together nicely. I just turn down the (digital) gain on the more sensitive amps.

The DCX can be controlled from the front panel or via free PC software. The PC software will run without a DCX so is great for learning how to use the DCX.

The microphone input/auto delay feature is easily fooled so I don't use it. As for using the DCX as a microphone pre-amplifier outputting to REW...I've never tried it but the PC software would show if the necessary internal links are possible. The DCX itself doesn't measure room response.

[Otto]

bjs wrote:

The DCX can be controlled from the front panel or via free PC software. The PC software will run without a DCX so is great for learning how to use the DCX.

Where can I get that software? I looked at the Behringer site, especially around the DCX2496 pages, and I could not find it. I'll have another look, but gimme a link if you can.

Thanks!

[Otto]

Nevermind -- it's so much on the front page that I didn't even see it. I thought that icon was just that of the 2496 itself; I didn't know it was a link.

Duh....

[fackamato]

Otto wrote:

Where can I get that software? I looked at the Behringer site, especially around the DCX2496 pages, and I could not find it. I'll have another look, but gimme a link if you can.

Thanks!

http://www.behringer.com/DCX2496/DCX2496_V1_16.zip

[WmAx]

hddummy wrote:

it does, but that is post Analog-Digital Conversion, so it doesn't affect the bit usage of the input signal at all. Again, this is only splitting hairs unless you really care about taking advantage of the full 24bit processing.

The DCX seems to have analog input gain blocks and analog output gain blocks. The unit's noise floor clearly decreases as you reduce the output gains. And the input gains would seemingly have no way to prevent clipping when reducing attenuation if you exceed the input capacity of the ADC stages. If it is digitally attenuated, it's superbly executed and acts exactly like an analog equivalent in all practical situations. Regardless, if you have a clean consumer level signal, it will boost it, no problem. I have never had to use a converters when feeding A DCX unbalanced consumer lines. At the very most, a ground loop isolation transformer may be needed in some rare cases.

-Chris

[hddummy]

There you have it. Real world, hands-on use trumps by the books planning almost every time.

[myn]

WmAx wrote:

The DCX seems to have analog input gain blocks and analog output gain blocks. The unit's noise floor clearly decreases as you reduce the output gains. And the input gains would seemingly have no way to prevent clipping when reducing attenuation if you exceed the input capacity of the ADC stages. If it is digitally attenuated, it's superbly executed and acts exactly like an analog equivalent in all practical situations. Regardless, if you have a clean consumer level signal, it will boost it, no problem. I have never had to use a converters when feeding A DCX unbalanced consumer lines. At the very most, a ground loop isolation transformer may be needed in some rare cases.

-Chris

I can barely get the input LED's on the side of the DCX registering -20. This going from my Panasonic XR55 LFE out into using a monoprice RCA out to XLR cable.

Are you saying as you boost the input gain the LED's reflect this input gain adjustment?

So do you boost the input or output gain? And is there an advantage to each?

[sfdoddsy]

I think we are discussing this on another forum, but the answer is no.

All the adjustments regarding gains on the DCX happen after the A/D conversion.

From what you have said elsewhere you have done a test and are unable to get the input gain LEDs above -20. How did you do the test?

I'm assuming you switched off the power amp and simply turned up the prepro to maximum volume and observed the LEDs? What input signal did you use? I'd suggest trying full range pink noise to remove the source as the culprit. There are test discs that have this, but it is easier to use an RTA program like TrueRta (www.trueaudio.com). The basic program is free, if limited, but all you need is the pink generator.

Set your prepro to the highest possible xover, although I think the Panny only has one. Speaking of which, how have you done the Panny speaker setup? If set to small it automatically crosses at 120ish (from memory). If to large you will only get the LFE output. But it may not do bass management properly and this could be your culprit.

To check the bass management, try this: Instead of feeding the DCX the LFE output, feed it the left or right front output. Set it up as two channels only, no sub and mains Large. In other words a full range signal.

Then play the pink noise, or indeed another loud signal, with the Panny volume at maximum. IMPORTANT: power amp off.

If the DCX is still getting a low signal, go into the Speaker Level menu and turn the mains to the maximum and try again. If this fails you are basically stuffed. The Panny just doesn't have the juice.

If this test does get you a fuller signal, I'd try turning up the subwoofer level, or the LFE level when you go back to your normal setup.

When I do this test, I can clip the input gains on my DCX with the XLR outputs at 0dB or so and the RCAs at a few more more.

Mind you, given you are only using the DCX for the sub, the A/D bitrate is probably not a huge issue. The advantage (if any) of 24 bit is in the high end, not the low. Even at -20dB the DCX should be coasting along when converting the signal.

Try a simple bypass test.