Behringer DEQ2496 Equalizer Review

See also @gixxerwimp's Dummy's Guide to using the DEQ2496 Here:
https://www.superbestaudiofriends.o...ehringer-deq2496-digital-eq.9295/#post-306727

Behringer has a horrible reputation going back years now. Something about them ripping off a Mackie board from almost twenty years ago which they have never been able to escape. And also units that stopping working after the warranty expired. Both my DCX2496, purchased over ten years ago, soon developed issues with inputs or outputs not working. I think that stuff is long past and it's time to move forward. The Behringer Ultra Curve Pro DEQ2496 seems to be working well after a few years - cross my fingers. Heck, they've managed to stay in business that long, so somewhere along the line, I'm sure they've improved their quality control. I'd still be hesitant to use for them pro (money making) work, but at home, it should be fine.



So what is the Ultra Curve Pro DEQ2496? It's a inline analog and digital EQ. The use case I will cover here is that of a digital equalizer. I'm not interested in the analog EQ function because there is an AD/DA conversion required which I would rather skip (what would be the point of a four or five figure DAC if we are just going to put this in the analog signal path?).

Being a piece of pro gear, the only real (that is excepting Toslink) digital inputs and outputs it supports are AES. See below photo.


Do not despair if our digital sources and DA converters use RCA or BNC SPDIF, we are not SOL. I picked Sescom AES to SPDIF and SPDIF to AES transformers from Amazon for cheap pictured below. (Note that I don't see Amazon carrying the Sescom SPDIF to AES part anymore, so I provided a link to the more expensive Neutrik part). If necessary, use RCA / BNC adapters.

Sescom SES-AES-EBU-1 XLRF to 75 Ohm BNC Female AES/EBU Impedance Transformer
Neutrik NADITBNC-MX 75 Ohm BNC F to 110 Ohm XLR M Adapter



Note that is is possible that we can get away with cheater XLR to RCA cables that tie the "-" to ground for AES to SPDIF conversion. However, I wanted to play it safe with a more proper conversion. With the Behringer DCX2496 digital crossover where I used the adapter cables, I didn't get consistent results with digital signal not always locking on.

So getting the preliminaries out of the way, how might I use this? Here are two examples:

pi2AES -----AES----> DEQ2496 ----AES----> Sescom Transformer ----SPDIF----> Schiit Gungnir DAC (BNC 75-ohm input)
pi2AES -----AES----> DEQ2496 ----AES----> Modius (AES 110-ohm input)

 

So basically why the heck would I use a hardware EQ instead of software? Well, in the case of pi2AES and Volumio, the EQ plug-ins kind of suck. Also, some people such as myself prefer a physical interface. I've found a small learning curve with Behringer gear - I will go through the basics to get started quickly:

Click the IO button on the right panel. Select input via the main dial.


The bypass button shows us all the DEQ2496's features. There is a limiter, a dynamic EQ (might come in useful for limiting bass overexcursion for Focals and SR1a at high SPL), stereo width, etc. I plan on covering just the graphic EQ and parametric EQ functions here.
Here is parametric EQ screen:

And graphic EQ screen:


Normally, I've tended to prefer the PEQ. However, I've found myself preferring the GEQ during my time with the DEQ2496 for the following reasons:

1. The band granularity is quite good with 1/3 octave bandwidth per slider.
2. The DCX2496 has a "True Response" option in the utility menu. When this is turned on, it smooths the EQ function. I will give you a demonstration of how it works in later post via a measurement.

 

One thing I wanted to get squared away is how to split the left and right EQs from each other. This was actually the most difficult part of the interface! Normally the left and right channel EQs are linked and there is no reason to change that. With speakers in a uneven funky room, we may want to apply individual EQ to each channel. This may also ring true with compression drivers which have a tendency of not always being exactly the same with each other depending how precisely the diaphragm is aligned. It took me forever to find how to un-link the left and right channels, therefore I finally consulted the manual.

All we need to do it press the utility button, scroll down to the channel mode (second line from top) via the small top knob, and change from stereo-link to dual-mono with the large knob.



Also be sure to dial in negative gain offset so you don't go past 0dbFS. Digital clipping has a hard limit. Set negative offset so that we don't clip. The DEQ2496 has an RTA with peak hold function so we can monitor this. The button is on the very top left of the unit. Don't be a digital EQ noob!

 

Getting back to the "True Response" option, here is an GEQ profile that I set up:


And here are the measurement results for Uncorrected vs True Response:

Note that True Response will apply a smoothing function, hence the small dips at the sides.

Here are some signals to check for jitter. Note the y-axis scale goes from -200dbFS to -100dbFS. We are zooming in on the minutiae here.

12kHz signal at -1dbFS, 48kHz sampling rate, one pass, no averaging


12kHz signal at -1dbFS, 48kHz sampling rate, one pass, average of 4


12kHz signal at 0dbFS, 48kHz sampling rate, no averaging

This would appear to be jitter given the symmetry around the 12kHz signal.

12kHz signal at 0dbFS, 48kHz sampling rate, average of 4


It would appear that any jitter is transitory and disappears when there is a continuous output. In any event, the jitter is so amazing low, lower than what current electronics are capable of, so none of this is any concern. It's all academic.

SUBJECTIVE IMPRESSIONS

Subjectively, and I think this is the most important for the audience here, the DEQ2496 seems pretty darn transparent. Although it boggles the mind that digital sources and transports can actually have a sound, the DEQ2496 seems to transmit the sound of the digital source or transport through without imparting any of it's own. For example, the Theta Data III sounds like a Theta Data III. The Toslink output from the Marantz CD6006 sounds like the Toslink from it! The pi2AES sounds like the pi2AES. If you don't believe that digital sources actually have a sound, then just feel free to disregard what I just said as the ramblings as a madman.

 

So let's have some fun. Did I mention that the DEQ2496 also has a built-in pink-noise generator (selectable from the input source screen)? It can also auto-calibrate (those things are dumb, so I prefer calibrate manually).

Here is the RAAL Requisite SR1a on a miniDSP EARs. Note pink noise generator being selected below on the DEQ2496.


Here is the RTA using SBAF compensation
YEL = no EQ
GRN = EQ applied


Note that I intentionally dropped everything below 40Hz. I listen loudly, so would prefer the keep excursion under control. Not that this really does much good since I am boosting 50-80Hz, which will already add a ton of excursion already.

Here are the DEQ2496 GEQ settings with True Response turned on.


Go have fun guys!

 

^ Hahahahahaha. Maybe unfair, but pros don't want to be seen using Behringer. It's embarrassing.

 

Be careful what you wish for. $350 could be tough if it's a balanced version, as a lot of Schiit's gear seems to be headed in the mid and high ranges. Another request would be use of actual inductors for the EQ, but $$$.

 

For EQ on analog signals, the dbx is much better then the Behringer. There's still an AD/DA on the dbx stuff.

For pure analog EQ, discrete parts with LC circuits is best. No gyrator bullshit with opamps.

 

Holy crap, I didn’t even see the guide you wrote. Will add a link to it in first post.