Parametric digital equalizer (with digital in/out)

[haraldo]

I really want to buy a parametric digital equalizer now.....
Thought about all these room correction systems, but they are quite expensive and.... I will probably want to go for a lyngdorf or deqx, but when buying, I want to do it right the first time, coz these things have a cost.......
But I don't think there's any way I'm not going there..........

well, some of these systems do nothing that a parametric equalizer cannot do, except for, well.... The deqx corrects phase too, so that's a very interesting thing.....

Very nice entry fees for Behringer dcx2496 and deq2496 (low price)
Anyone using these things?

Anyone using the deqx preamp?

 

[Savant]

Whether or not PEQ or some other "room correction" package is right for you depends on what you expect it to do. What kind of room / system problem(s) are you experiencing that have prompted you to investigate these types of solutions?

 

[haraldo]

Well

My question was more focused on experiences with these different boxes, rather than the room issues themselves, especially the deqx, which may seem very elegant for DIY'ers, specially whereas it provides 3 way active digital crossover and many nice features to aid in getting an active loudspeaker system running.... and providing means of room correction.

And the deqx has a volume control and serves as a full remote controlled preamp, whereas the Behringer boxes has nothing like that. Any way of getting a volume control integrated into the Behringer Ultdradrive?

The way I see it room correction may aid below 200Hz or sth, but not so much above that...
So below 200Hz it goes with combination of bass traps to control standing waves and decay and some equalizing ....

In general I believe the issue is how much work you are willing to do yourself and if you have the time and energy to do the hard work yourself you will get just as far as any of the "automatic" room correction systems. I presume, yes?

 

[Savant]

Others will have to chime in on their experiences with different devices. I have used the Behringer unit (DEQ2496, I think) to add a small amount of cut to a very low room mode. It worked much better than I expected.

Beyond using this type of "correction" for frequencies in the lowest octave or two, I haven't ever come across situations that would have benefitted from EQ. But that's just me.

 

[Swerd]

Haraldo

I have been thinking about this same subject as well – to use a parametric equalizer (PEQ) to correct uneven bass response due to room reflections. I have looked for what PEQs are available, at what price, and how they may be integrated into my existing system (see below).

The real problem with using PEQ to correct bass response due to room reflections, is how do you know what to correct? There is free software that apparently works well for this, Room EQ Wizard. It generates test signals, measures in room frequency response, presents the results graphically, and shows simulated freq response curves that would result with various PEQ notch filters it suggests or those you choose. It does require that you have a measuring microphone, such as a Behringer ECM800 and a way to connect it to a computer, such as this preamp box. It can also work with a Radio Shack SPL meter, although I don’t know those are available in Norway.

I have downloaded this software, and have ordered a microphone and preamp box and will try this. In the meantime I am exploring what type of PEQ to buy. One advantage of either of the two less expensive Behringer PEQ boxes is that they can communicate directly with Room EQ Wizard, simplifying their use. Perhaps the least expensive one will be enough to correct bass from 20-200 Hz. All 4 of these Behringer PEQ boxes work for only 2 channels, so if you must equalize a typical HT system, you would need at least three boxes. And all 4 of these must be installed between preamp and amplifier.

The 4 different Behringer boxes have confusing names and model numbers:

DCX2496 (Ultradrive Pro Digital Crossover $300 US) Highly capable for PEQ and active crossovers.

DEQ2496 (Ultracurve $300 US) Highly capable and said to be complex to learn to use.

FBQ2496 (Feedback Destroyer Pro $150 US) Capable of 40 notch filters, 20/channel.

DSP1124P (Feedback Destroyer Pro $100 US) Capable of 24 notch filters, 12/channel.

As you had mentioned there are two more automated and expensive approaches, DEQX and Audyssey. Both seem to be highly capable and very expensive – out of my price range. I’m not sure about DEQX, but Audyssey is automated, is meant to be professionally installed, and does not let the operator make choices. Audyssey also incorporates a simplified version of its room EQ into a number of Denon and Onkyo receivers. Again, with it you do not have any manual control.

There are also a few higher priced preamp/processors or AV receivers that have built-in PEQ abilities. These are various B&K receiver & pre/pro models (USA), TAG McLaren AV32R DP & AV192R AV processors (UK), and Classé SSP-800 (Canadian). There may be others that I am unaware of. I am looking for suitably priced used B&K receivers (AVR 305/307 or 505/507) or preamp/processors (Reference 30 or 50). They contain built-in digital PEQ that allow one to create up to 5 notch filters in the 20-300 Hz range. This feature works in all its channels.

I hope this information helps.

 

[Savant]

Again, my experience is limited. However...

DEQ2496 (Ultracurve $300 US) Highly capable and said to be complex to learn to use.

...I would disagree that the DEQ2496 is complex, at least in terms of the PEQ portion of it. I had it out of the box and up and running in under 30 minutes. My client did have to rework his signal chain to accommodate it properly. But even that would be hard to describe as "complex." IMO, very straightforward to use. YMMV, of course.

 

[haraldo]

Quite a few more options though....

Like Holm Acoustics DSpre1, which corrects for phase and response and that's got a built in digital x-over and sth like possibility for... I believe it's 25.000 eq. points
I got a demo of this and you can do equalization simply by dragging the response curve the way you want it and the system will calculate correct parametric equalizations to make this happen... Of course it's more expensice than the pro Behringer gear, but this is nice stuff

And holm has freeware that measures response and phase, and that should work with any kinds of soundcards, at least that's what's being claimed.

And the Lyngdorf products.....
http://www.lyngdorfaudio.com/

Ideally, perhaps... the way to go is the Behringer Ultradrive, because of the builtin crossover, but there is a major major problem with this unit, there is no volume control, and if you want that you will have to:
a) use digital volume control in the chain before the ultradrive, so you will lose resolution, lots of it...
or
b) use a 6 channel preamp in the chain after the ultradrive
and this is expensive, cannot remember to have seen an affordable 6 channel balanced preamp anywhere

So anyway, you bang your head into a wall of issues if you want parametric eq + digital x-over in an affordable unit.... for stereo usage.

And it would be interesting to hear about any kinds of experiences with these products.....

 

[haraldo]

sth wrong with url to holm acoustics, here it is:
http://www.holmacoustics.com/dspre1_introduction.php

http://www.holmacoustics.com/holmimpulse.php

And I was wrong, there is only 16.000 equalization points, not 25.000

And in a way, I'm not sure if the deqx, Lyngdorf, Holm or Audyssey products are really that expensive, all considered, thinking about all these man hours behind this, like the deqx has some million lines of source code in the software, and considering what Lyngdorf and Holm products do... hmmmm... difficult this is....

 

[WmAx]

Quite a few more options though....

Like Holm Acoustics DSpre1, which corrects for phase and response and that's got a built in digital x-over and sth like possibility for... I believe it's 25.000 eq. points
I got a demo of this and you can do equalization simply by dragging the response curve the way you want it and the system will calculate correct parametric equalizations to make this happen... Of course it's more expensice than the pro Behringer gear, but this is nice stuff

And holm has freeware that measures response and phase, and that should work with any kinds of soundcards, at least that's what's being claimed.

And the Lyngdorf products.....
http://www.lyngdorfaudio.com/

Ideally, perhaps... the way to go is the Behringer Ultradrive, because of the builtin crossover, but there is a major major problem with this unit, there is no volume control, and if you want that you will have to:
a) use digital volume control in the chain before the ultradrive, so you will lose resolution, lots of it...
or
b) use a 6 channel preamp in the chain after the ultradrive
and this is expensive, cannot remember to have seen an affordable 6 channel balanced preamp anywhere

So anyway, you bang your head into a wall of issues if you want parametric eq + digital x-over in an affordable unit.... for stereo usage.

And it would be interesting to hear about any kinds of experiences with these products.....

I use an analog signal to the DCX input. That input is the analog pre-amp outputs. Loss of resolution is no issue of practical consequence here; it is a 24 bit system and with gains set correctly, at no time do you have any type of audible noise/hiss. Noise/hiss is the only concern practically, and the unit has a large range comparable to high quality analog systems.

-Chris

 

[haraldo]

I use an analog signal to the DCX input. That input is the analog pre-amp outputs. Loss of resolution is no issue of practical consequence here; it is a 24 bit system and with gains set correctly, at no time do you have any type of audible noise/hiss. Noise/hiss is the only concern practically, and the unit has a large range comparable to high quality analog systems.

-Chris

What I heard from other pro users is that the AD converter in the DCX is not so good and that results are suboptimal when using analog input, compared to using the digital input (when you have a digital signal, that is)

A friend of mine that's a sound technician.... is not 100% happy when using the analog input of the DCX, which is why I'm somehow skeptical to the analog input... It could be because of other things, though....

If you have a digital signal, I wonder about the sense of going from Digital to Analog, then Analog to Digital again in the DCX and then back to Analog again.... like 3 AD or DA conversions.... when one should do it.....

 

[WmAx]

What I heard from other pro users is that the AD converter in the DCX is not so good and that results are suboptimal when using analog input, compared to using the digital input (when you have a digital signal, that is)

A friend of mine that's a sound technician.... is not 100% happy when using the analog input of the DCX, which is why I'm somehow skeptical to the analog input... It could be because of other things, though....

If you have a digital signal, I wonder about the sense of going from Digital to Analog, then Analog to Digital again in the DCX and then back to Analog again.... like 3 AD or DA conversions.... when one should do it.....

I seriously doubt any legitimacy of those claims. I would suspect these statements are just the same old subjective ones, based on psychological reasons, not actual audible ones, as is true with most any other issue in audio. It acts like a transparent device so far as I can tell. And measurable performance is great also; nothing to suggest an audible coloration. There may be multiple AD/DA conversions, but practically speaking, the conversion is of such low distortion and excellent SNR, that it's non-consequential. But if the mere idea bothers you that much, then you can rest assured you will probably 'perceive' a difference even if there is not one.

-Chris

 

[haraldo]

I seriously doubt any legitimacy of those claims. I would suspect these statements are just the same old subjective ones, based on psychological reasons, not actual audible ones, as is true with most any other issue in audio. It acts like a transparent device so far as I can tell. And measurable performance is great also; nothing to suggest an audible coloration. There may be multiple AD/DA conversions, but practically speaking, the conversion is of such low distortion and excellent SNR, that it's non-consequential. But if the mere idea bothers you that much, then you can rest assured you will probably 'perceive' a difference even if there is not one.

-Chris

Well, these claims came from a former professional sound technician that worked professionally as a lead technician with Cure and Dire Straits, so I'm not going to leave this with empty talk, and .... ok, I'm going to check with him what these things are about.....

hehe, yes...... if it bothers, me I will probably hear a difference that's not there

Do you employ the crossovers in the DCX too.... are you running a fully active system with no passive x-overs anywhere?

 

[haraldo]

Chris, one thing I'd really like to hear your opinions about.
If you disregards the phase correction that some systems do......

Do you think there is anything that any of these room correction system does that you cannot do with the Behringer DCX2496 or DEQ2496?

the idea being that you just correct what you want... like... "set and forget"
And disregarding the fact that there may be a lot of hard work to get all settings correct with a DCX or DEQ.

Or is it really a fact that you can get even better results with a DCX or DEQ because you have much more control? many of the room optimization won't even let you control any of the PEQ settings

 

[WmAx]

Well, these claims came from a former professional sound technician that worked professionally as a lead technician with Cure and Dire Straits, so I'm not going to leave this with empty talk, and .... ok, I'm going to check with him what these things are about.....

hehe, yes...... if it bothers, me I will probably hear a difference that's not there

Do you employ the crossovers in the DCX too.... are you running a fully active system with no passive x-overs anywhere?

I really care not whom he worked for or his position. He is no more immune against bias than me or any other human.

I use only fully active crossovers today. I have two systems, and both are fully active. The only passive component is a large capacitor on tweeters to protect against any potential LF transients upon turn on/turn off.

-Chris

 

[WmAx]

Chris, one thing I'd really like to hear your opinions about.
If you disregards the phase correction that some systems do......

Do you think there is anything that any of these room correction system does that you cannot do with the Behringer DCX2496 or DEQ2496?

the idea being that you just correct what you want... like... "set and forget"
And disregarding the fact that there may be a lot of hard work to get all settings correct with a DCX or DEQ.

Or is it really a fact that you can get even better results with a DCX or DEQ because you have much more control? many of the room optimization won't even let you control any of the PEQ settings

I'll tell you... I don't think phase correction is a big deal. The inverse phase change when you apply a correction to a LF mode with a normal parametric EQ is actually correcting the initial phase modification; because the room modes are a minimum phase phenomenon under about 80Hz or so in a regular sized room. The frequency response anomaly and phase are directly related to each other, so correcting it results in correction. And as far as the phase error the crossovers in the speakers themselves create; this is non-consequential according to the credible research that tested for audibility under different conditions/environments with many trained listeners. The only way to get really high quality correction in the 100-300Hz band, is with proper room acoustics treatments, and of course, the 80 and under band corrected with EQ is only good in a very limited sitting position.

It does take a while to correct with a manual device like the DCX, this is true. But it does a very good job.

-Chris

 

[haraldo]

I really care not whom he worked for or his position. He is no more immune against bias than me or any other human.

Thx and you're probably right Chris...
I just had this thought that somebody being within audio profession at least would be less influenced by these things
But this has been proven wrong many times......

And thanks for all this info......

 

[WmAx]

Thx and you're probably right Chris...
I just had this thought that somebody being within audio profession at least would be less influenced by these things
But this has been proven wrong many times......

And thanks for all this info......

As one last comment: if I detected or had reason to believe any significant level of audible degradation occurred, I would not use the DCX2496 in my systems. I have extraordinary demands/standards for audio quality; well beyond the standard audiophiles. I have invested years of research/studying/experiments (of the most laborious type; insisting on the most objective/scientifically valid experiments/data possible) in order to be able to achieve the sound quality that satisfies me. Make no mistake, even my computer sound system will flat out humiliate the majority of high end high cost audiophile systems and high end pro studio monitor systems. It is also a fully active 3 way system, with ultra linear response(+/- 0.7db up to 16kHz), extreme dynamic capability, incredibly low resonance and I have installed complete acoustical treatment of all surroundings.

-Chris

 

[muttondraw]

I got into room correcting some years ago when we moved house and I was unsatisfied with the sound of my hi-fi in the lounge. It was basically okay except for a couple of peaks in the bass response. The room would tend to resonate on certain bass notes on certain tracks. I found myself listening to the resonance rather than listening to the music, very irritating.

I bought a Tact 2.0 room correction system and lived with it for 18 months I was never quite satisfied with the correction. I was constantly trying new targets and recalibrating, but it never quite got it right. It was almost there so many times but was ultimately frustrating because it was a too heavy handed approach. It would solve some problems but introduce others. I always felt the sound that it created was overly corrected, what I wanted was a system which would leave the sound basically untouched and just reduce the significant bass peaks.

2 years ago I bought a DEQ-2496 to play with and experimented with EQing the bass response. What a different experience. The 2496 was very controllable, very clean sounding and just addressed the specific frequencies I was having a problem with. All in all I have been very impressed with it, my only real gripe is that there isn't quite enough low frequency resolution to hit a troublesome peak bang on unless it happens to sit at one of the frequency intervals the DEQ-2496 can tune to.

I bought 2 more DEQ-2496s and fed 5.1 digital to the DEQs from the digital outs on a Meridian 561. I then bought 2 Lavry DA10s (to give me 4 channels of dejittered DAC) these are used for L, C, R and I use the DACs in the 3rd DEQ for surround. This then goes to an Arcam C30 with multichannel input for level. Last year I modded an Oppo 980H to get higher resolution multichannel digital outs from SACD, this is fed digitally to the DEQ-2496s too.

The best place to start with correction is to get some computer software and a mic to measure your room (don't rely on the DEQ-2496 for measurement), work out where the problems are and correct as best you can through speaker placement and mechanical absorption. Then use EQ to address any problem peaks below 200Hz. You can actually do a lot by just changing speaker and listening position. but you really need a mic and some software so you can be objective about the changes you are making. I used a behringer ECM8000 microphone and Fuzzmeasure running on a Mac for measuring the room, but there are loads of options out there.

Cheers

Martin

 

[peerlesser]

Quite a few more options though....

I think the most common is nowadays Anti-Mode 8033 for around $300.

http://www.avsforum.com/avs-vb/showthread.php?t=1028464&page=25

http://www.hometheatershack.com/forums/bfd-forum/11699-testing-dspeaker-anti-mode-8033-a.html