Behringer DEQ2496 Ultracurve Pro DSP Review

[bobbooo]

Ah, thanks for that link re the online calculator (just have to remember to use negative numbers) and that tallies with the 10dB rule that Amir told us about. You did a typo in your calculation though, the number I bolded & underlined in your post should say -60dB.

Thanks, fixed.

In terms of thinking about the relevance of high SINAD electronics, headphones have lower measured distortion than speakers (I've only just kinda realised this contrast!), with headphones often having less than 1% distortion which I believe is unheard of in speakers. Could it be that the low distortion of some headphones could mean that higher SINAD numbers are more relevant when it comes to headphone listening? Is there a way of calculating a relevant SINAD target in conjunction with headphone listening given headphones low distortion.....it would be quite useful to have a ballpark practical target for SINAD for electronics when used in combination with headphones? On the same token headphones don't suffer from room modes (which cloud the sound) and headphones also don't have the long decay times that speakers have in rooms (which are both particularly applicable in the bass area where distortion in speakers is often highest), so I'm thinking this all adds up to headphone listening being a higher resolution experience in general that might be able to define greater nuances (SINAD) in electrical gear? (Of course there's the HRTF/HpTF problem with headphones that would decrease resolution (which speakers don't suffer from), but some of that can be EQ'd out).

EDIT: an additional thought re the application of high SINAD electronics, when you EQ then you need to apply a negative preamp, which effectively means you're reducing your SINAD, so you need to start off with a higher SINAD product if you're taking EQ into account. I guess you're typically talking about a -5 to -10dB preamp when EQ'ing, so I guess this translates to removing 5 to 10dB from your SINAD. So taking this into account your want your DAC to have about 15-20dB better SINAD than your downstream devices.

Yes, headphones typically have lower distortion than speakers. Probably the lowest distorting headphones ever made are the $60,000 Sennheiser HE1 at 0.01%, which translates to -80 dB. Allowing for negative preamp while EQing as you say, this means your DAC would only need to have 15-20 dB less distortion than this and so a SINAD of 95-100 dB, giving a combined distortion of -79.9 to -80 dB to 1 decimal place i.e. an inaudible addition of distortion. Most smartphones people already have in their pockets, e.g. the three and a half year-old Samsung Galaxy S8 with a SINAD of 96 dB, or the $9 Apple dongle with a SINAD of 99 dB will therefore add no audible distortion to the lowest distorting headphones in the world. The DAC SINAD required for effective transparency with a typical headphone would obviously be even lower.

But there's still one thing that's being neglected in this picture - the distortion in the music production chain. Just like speakers in the audio reproduction chain, mics will likely be the highest distorting link in the production chain, both being transducers of course. If we take a best-case (or at least excellent case) mic distortion of 0.1% (-60 dB), this means playback chain SINAD would only need to be above 75-80 dB, giving a (worst-case, in-phase) combined distortion of -59.9 to -60 dB (to one decimal place) and so an insignificant distortion contribution from the playback chain (for headphone listening, required SINAD for speaker playback would be even lower due to their transducer distortion being typically higher than such a low distorting mic). And none of this is even considering absolute distortion audibility limits, which are likely to be even higher, especially when listening to actual music and the perceptual masking that goes along with it.

 

[Robbo99999]

Thanks, fixed.


Yes, headphones typically have lower distortion than speakers. Probably the lowest distorting headphones ever made are the $60,000 Sennheiser HE1 at 0.01%, which translates to -80 dB. Allowing for negative preamp while EQing as you say, this means your DAC would only need to have 15-20 dB less distortion than this and so a SINAD of 95-100 dB, giving a combined distortion of -79.9 to -80 dB to 1 decimal place i.e. an inaudible addition of distortion. Most smartphones people already have in their pockets, e.g. the three and a half year-old Samsung Galaxy S8 with a SINAD of 96 dB, or the $9 Apple dongle with a SINAD of 99 dB will therefore add no audible distortion to the lowest distorting headphones in the world. The DAC SINAD required for effective transparency with a typical headphone would obviously be even lower.

But there's still one thing that's being neglected in this picture - the distortion in the music production chain. Just like speakers in the audio reproduction chain, mics will likely be the highest distorting link in the production chain, both being transducers of course. If we take a best-case (or at least excellent case) mic distortion of 0.1% (-60 dB), this means playback chain SINAD would only need to be above 75-80 dB, giving a (worst-case, in-phase) combined distortion of -59.9 to -60 dB (to one decimal place) and so an insignificant distortion contribution from the playback chain (for headphone listening, required SINAD for speaker playback would be even lower due to their transducer distortion being typically higher than the mic's). And none of this is even considering absolute distortion audibility limits, which are likely to be even higher, especially when listening to actual music and the perceptual masking that goes along with it.

Wow, that's MADNESS re the HE1, it's £51,000 here! https://en-uk.sennheiser.com/sennheiser-he-1
Good point about the mic distortion rate in recorded music, but I suppose there's some electronic music where some elements of the sound is just created (electronic music) rather than recorded, although maybe it started life as a recorded sample at some point. It's all probably pretty negligible to be honest. I did indeed choose my equipment based on SINAD as one parameter (SoundblasterX G6, Topping E30, JDS Labs Atom Headphone Amp), so I'm part of the "yes please I'll have the best measuring gear!", but hell most of us have enough SINAD for our speakers and headphones, no stress. I was pretty sure I noticed a quality difference in the sound once I upgraded my headphone amp from the included amp in the SoundblasterX G6 to the JDS Labs Atom when used with my K702 headphones, but that might not be SINAD related (might be another factor) or it might be a placebo.....although thinking about it using a seperate headphone amp allows me to run the DAC at a higher output level as volume is controlled by the headphone amp so that might play into it too. Praps there's more to amps than there is to DACS when it comes to noticeable sound quality, the mantra often goes speakers/headphones -> amp -> DAC in order of importance I keep hearing.

EDIT: about that Sennheiser HE1 at that link above, there does seem to be quite a lot of phooey and witchcraft associated it if you read about it at that link, would love to see it measured on ASR, imagine bringing down a £51,000 headphone package (it includes amp (tube!))! Or maybe it would measure awesomely!

 

[sam_adams]

Thanks, I was being lazy and hoping for a DEQ2496 schematic so I'd have the exact part numbering, but if I must trace the circuit, so be it. In the case of the SRC2496 above, I'm thinking that C86 (100p) and C43 (20p) might be all I need to upgrade to C0G types. And although much larger than the stock part, I could probably squeeze a film capacitor in there, replacing the 47 uf coupling capacitor C94 (but is it worth the bother @ $7.33/ea?) Have I missed anything else which might give me lower THD?

The DEQ schemetics seem to not have leaked out like the other device schematics have. I haven't seen them at all.

Instead of just changing a few capacitors, you might get better results by taking a look at Jan Didden's power supply upgrade if your device has the SMPS in it or looking for a good, non-eBay, linear supply to replace the minimal supply that's already there if the device has the linear supply. If the device has the linear supply, shielding the transformer and dressing the wires might help to reduce noise. The NJM4580s would be something else to look at as there are devices that have better distortion and noise specs.

 

[bobbooo]

Wow, that's MADNESS re the HE1, it's £51,000 here! https://en-uk.sennheiser.com/sennheiser-he-1
Good point about the mic distortion rate in recorded music, but I suppose there's some electronic music where some elements of the sound is just created (electronic music) rather than recorded, although maybe it started life as a recorded sample at some point. It's all probably pretty negligible to be honest. I did indeed choose my equipment based on SINAD as one parameter (SoundblasterX G6, Topping E30, JDS Labs Atom Headphone Amp), so I'm part of the "yes please I'll have the best measuring gear!", but hell most of us have enough SINAD for our speakers and headphones, no stress. I was pretty sure I noticed a quality difference in the sound once I upgraded my headphone amp from the included amp in the SoundblasterX G6 to the JDS Labs Atom when used with my K702 headphones, but that might not be SINAD related (might be another factor) or it might be a placebo.....although thinking about it using a seperate headphone amp allows me to run the DAC at a higher output level as volume is controlled by the headphone amp so that might play into it too. Praps there's more to amps than there is to DACS when it comes to noticeable sound quality, the mantra often goes speakers/headphones -> amp -> DAC in order of importance I keep hearing.

Yeah it's a bonkers amount of money to pay for a pair of headphones...especially considering the frequency response variation Oratory measured been two HE1 units - criminal at that price.

True, I was focusing on recorded music really, and the requirements for transparency may actually be higher for electronic music, contrary to common audiophile 'wisdom' that says you need the highest quality playback chain to reproduce lifelike live music performances - they rarely consider distortion from the mics in these scenarios. I suppose there could be an argument that as electronically created sounds don't have a real-life counterpart, unlike live recordings, 100% audible transparency is less important in these cases, as there is no 'real' reference to compare them to (personally I don't buy this argument, just throwing it out there). But even if not using mics, other 'pro' audio equipment used in music production often has relatively high distortion compared to typical consumer playback electronics, so the SINAD needed for audible transparency is still likely not very high for purely electronically created music either, and consider your headphones are probably a weaker link distortion-wise anyway.

So regardless of exact thresholds of audibly significant added distortion, I think the general rule of thumb holds that each link in your audio playback chain only requires around 15-20 dB higher SINAD (accounting for EQ preamp, likely only 10-15 dB without) than the highest distorting link in the whole combined production-reproduction chain, in order to guarantee not making the chain any (audibly) weaker than that weakest link. And that weakest link is usually either the mics at one end for recorded music, or your speakers/headphones at the other, both with invariably significantly greater distortion than the vast majority of competently designed consumer DACs, amps etc.

 

[JeffS7444]

Instead of just changing a few capacitors, you might get better results by taking a look at Jan Didden's power supply upgrade if your device has the SMPS in it or looking for a good, non-eBay, linear supply to replace the minimal supply that's already there if the device has the linear supply. If the device has the linear supply, shielding the transformer and dressing the wires might help to reduce noise. The NJM4580s would be something else to look at as there are devices that have better distortion and noise specs.

I wish I could relocate that article as the author was methodical in his modifications, and the appeal of the modification was an order of magnitude improvement in the THD with only the most minimal of circuit changes, and he arrived at something much closer to the 0.0005%(!) THD spec of the stock opamp. Different opamps were tried in the stock circuit but had little effect.

 

[tvrgeek]

I had one of these when they first came out. Darn near 20 years ago. It does what they say, but the terribly long boot drove me crazy and it made ugly noises on powering up and down. Sound quality is dead on for what they built it for, cheap PA work. That is NOT a criticism. It does not impact the intended use. It is not a hi-fi unit and not sold as such. I do wonder if they have done any updates. Hard to believe some of the chips are still in production. I have had good luck with Behringer. A lot of function for the money. Their analog crossover sounded better though.

Jan Didden published quite a POOGE in AA. Big improvements.

 

[Wombat]

FWIW. DEQ power supply schematics:

https://maurmun.com/2010/10/05/the-behringer-dcx2496-power-supply/

http://www.awdiy.com/uploads/pdf/DEQ2496-PSU-DIY-v2-1.1.pdf


Cap replacement. Applies to DEQ2496 also:

Using the DEQ2496 in a HiFi system.



P.S. For those who can't leave things be: http://www.awdiy.com/

 

[AnalogSteph]

I wish I could relocate that article as the author was methodical in his modifications, and the appeal of the modification was an order of magnitude improvement in the THD with only the most minimal of circuit changes, and he arrived at something much closer to the 0.0005%(!) THD spec of the stock opamp. Different opamps were tried in the stock circuit but had little effect.

You may be talking about this thread.

 

[amirm]

True, I was focusing on recorded music really, and the requirements for transparency may actually be higher for electronic music, contrary to common audiophile 'wisdom' that says you need the highest quality playback chain to reproduce lifelike live music performances - they rarely consider distortion from the mics in these scenarios.

If I am listening to electric guitar whose amp distorts 200%, it is your position then that I should listen to said music on a playback system that generates say, 100% distortion?

So no, what is in the music is what is in the music. Distortion and all. Our playback system's job is not to add to it.

 

[Francis Vaughan]

I think he is arguing the opposite. Live musical instruments and analog recording components (microphones etc) with its inherent harmonic content may be more tolerant of additional harmonics, whereas synthesised electronic music is often much more pristine and possibly any additional distortion may be more obvious. I suspect that may true.

The curious weasel words from the likes of PSAudio clearly do try to suggest that their magical secret sauce is adding distortion to the sound to “improve” it.

 

[tvrgeek]

If I am listening to electric guitar whose amp distorts 200%, it is your position then that I should listen to said music on a playback system that generates say, 100% distortion?

So no, what is in the music is what is in the music. Distortion and all. Our playback system's job is not to add to it.

So many seem to miss this! Sound of tubes etc. ( their place is in the studio, preamps and mics if they so choose) What is also missed is some aspects of non-linear distortions can manifest themselves dynamically differently depending on topology. I suggest, the better any topology is executed, the less the differences. An example is VAS loading compensation vs transient miller. You can get the same static condition measures, but in an otherwise all things equal test, the difference is audible.

 

[JeffS7444]

You may be talking about this thread.

That's it, thank you!! Big help having someone already work out the part numbers and locations, saves me the hassle of having to place an order for the one SMD capacitor I overlooked!

 

[Fone]

I had one and it was a blast. I liked the UI. Alongside REW Software, the DEQ2496 was an intuitive teaching tool for audio and room acoustics. It definitely was not transparent so I sold it eventually.

There were a ton of mods on these, principally at diyaudio.com. I recall somebody found a bug (maybe in the firmware or DAC implementation but maybe that was the DCX; can't remember.

Here is a fun DEQ2496 mod by the Lampizator. His blogs are fun to read and filled with nice pictures
http://lampizator.eu/lampizator/transport/behringer/ultracurve/ultracurve.html

Scott Endler sold some mods years ago...and reviewed them too!
https://web.archive.org/web/20140810061537/http://mysite.verizon.net/vze4c5pt/id14.html

 

[jsm]

Same here. I use it for digital parametric EQ, with named presets for my speakers & headphones. Got it about 4 years ago, still works great.

I wonder if its pure digital section could be tested. For example, give it a known digital signal, pass it through and see if it modifies it. Add noise (it can dither 16, 20 or 24 bits, triangular or noise shaped) and check the noise profile. Apply a few parametric EQ bands and see if they cause any side effects other than the EQ itself.

All in the pure digital domain, of course, no A/D or D/A converters.

I speculate that it would have excellent performance for these pure digital functions; its weakness is the D/A and A/D converters.

This is so true, I suppose that 90% of the DEQ 2496 owners for HIFI purpose were expecting this kind of test, I had one, I already know that it is not a good DAC, and I don't use analog side, just the AES in/out between a yellowtec puc 2 and a YBA WD202 ofr PEQ correction. Sadly, this review is not what we are expected , but thanks to confirm the poor DAC performance anyway.

Amyr certainly dont know that it is more an accessible room correction device than anything else ^^.

And I prefer to use external soundcard+REW than the in-build tools for the room correction , I inject manually the correction result from REW, I never understand why this model is not include in the REW "pre made" list of hardware, had to create it manually too.

 

[anmpr1]

FWIW I heard on the Phillip McKnight Know Your Gear guitar show that Behringer is ceasing 'brick and mortar' sales. Below is a news link. A sad situation, but it is probably the wave of the future as we are all under varying degrees of house arrest lockdowns, for our own good we are told.

https://www.musictech.net/news/gear/music-tribe-factory-direct/

With Guitar Center in bankruptcy (and likely facing a lot of store closures), local outlets where one could check out and purchase inexpensive pro-oriented gear could possibly become history. Manufacturers have no incentive to ship gear to a retail outlet that is more likely than not to fail, and when the store is in bankruptcy the manufacturer can't get their goods back. Rumor has it that Fender is in out tens of millions of dollars in receivables from Guitar Center--product shipments that haven't been reimbursed, and may not be depending upon their situation.

The problem is--if the item is not what you want or is otherwise defective, you could take it back to the store, no hassle. Returns are not going to be that easy with direct sales. Returns will be at manufacturer discretion, and not the discretion of a middle-man store owner who has an incentive to keep a customer's good will. Also, the expense of return shipping will probably be born by the customer.

One other point Phil made regarding these 'cheap' pro products like Behringer (and Peavey). People look down on them from an absolute standpoint, but in Phil's words, they 'make the impossible possible'. If you don't have much money but want to get involved in the recording scene, these companies offer a way to do it on a budget.

 

[Stephen]

FWIW I heard on the Phillip McKnight Know Your Gear guitar show that Behringer is ceasing 'brick and mortar' sales. Below is a news link. A sad situation, but it is probably the wave of the future as we are all under varying degrees of house arrest lockdowns, for our own good we are told.

https://www.musictech.net/news/gear/music-tribe-factory-direct/

With Guitar Center in bankruptcy (and likely facing a lot of store closures), local outlets where one could check out and purchase inexpensive pro-oriented gear could possibly become history. Manufacturers have no incentive to ship gear to a retail outlet that is more likely than not to fail, and when the store is in bankruptcy the manufacturer can't get their goods back. Rumor has it that Fender is in out tens of millions of dollars in receivables from Guitar Center--product shipments that haven't been reimbursed, and may not be depending upon their situation.

The problem is--if the item is not what you want or is otherwise defective, you could take it back to the store, no hassle. Returns are not going to be that easy with direct sales. Returns will be at manufacturer discretion, and not the discretion of a middle-man store owner who has an incentive to keep a customer's good will. Also, the expense of return shipping will probably be born by the customer.

One other point Phil made regarding these 'cheap' pro products like Behringer (and Peavey). People look down on them from an absolute standpoint, but in Phil's words, they 'make the impossible possible'. If you don't have much money but want to get involved in the recording scene, these companies offer a way to do it on a budget.

I agree it's a budget tool for pro users , still there is a leeway to produce a better quality product, more expensive, more reliable, with a better screen targeting also HIFI enthousiast that could correct their room and speakers imperfections. They could also potentially make more money... I use it optical in/opt out and I am very happy with it.

 

[Andysu]

I have x2 DEQ2496 one in the rack the other one not racked up yet. I use the DEQ for Dolby Stereo Lt Rt MP 4.2.4 matrix as I can adjust the Lt Rt if misblanced.

 

[Brdbelgium]

Just brought the Berhinger to EQ the room. Killer investment... taking digital signal from the streamer before feeding the Topping E30.

300 euro with measurement microphone. He propose me the EQ which I more or less repected, I prefer to cut down the peak and avoid pushing too much. The correction proposed where quite small beside the bass area as I use vintage corner speaker having a lot or room re-inforcement (too much)

now I am flat till 40 hz. It is totally transparent as fully digital and improve a lot the result. In the era digital, a dsp is clearly a must have and I find funny to have so big upgrade with such ‘tool’ which make audiophiles scream Vade Retro Satanas.

 

[AdamG]

Just brought the Berhinger to EQ the room. Killer investment... taking digital signal from the streamer before feeding the Topping E30.

300 euro with measurement microphone. He propose me the EQ which I more or less repected, I prefer to cut down the peak and avoid pushing too much. The correction proposed where quite small beside the bass area as I use vintage corner speaker having a lot or room re-inforcement (too much)

now I am flat till 40 hz. It is totally transparent as fully digital and improve a lot the result. In the era digital, a dsp is clearly a must have and I find funny to have so big upgrade with such ‘tool’ which make audiophiles scream Vade Retro Satanas.

Welcome Aboard @Brdbelgium.

 

[Stephen]

Just brought the Berhinger to EQ the room. Killer investment... taking digital signal from the streamer before feeding the Topping E30.

300 euro with measurement microphone. He propose me the EQ which I more or less repected, I prefer to cut down the peak and avoid pushing too much. The correction proposed where quite small beside the bass area as I use vintage corner speaker having a lot or room re-inforcement (too much)

now I am flat till 40 hz. It is totally transparent as fully digital and improve a lot the result. In the era digital, a dsp is clearly a must have and I find funny to have so big upgrade with such ‘tool’ which make audiophiles scream Vade Retro Satanas.

Yes it's absolutely one of the best value investment in my setup.