DEQX --is your system up to par?
- Thread starter DaveyF
- Start date
It will be interesting to see what Dave thinks when he switched over permamently to the Vandersteens in his room.
For me as I have not done a setup yet. I will wait to hear it. I feel almost any device we buy can be improved upon.
But it must be done with caution. And listening first is paramount. I also have ps audio P10 ,s feeding my whole office rig.
And I am using multi wave as the output setting and it has improved every divide in the chain including my plasma.
As I know the unit does complete room correction , my intention is to use it as my 4 way active cross over and go from there . Presently I have a Yamaha d240 now given the unit is about 12 years old i am sure there will be improvements
Without using room corrections.
Al
But it must be done with caution. And listening first is paramount. I also have ps audio P10 ,s feeding my whole office rig.
And I am using multi wave as the output setting and it has improved every divide in the chain including my plasma.
As I know the unit does complete room correction , my intention is to use it as my 4 way active cross over and go from there . Presently I have a Yamaha d240 now given the unit is about 12 years old i am sure there will be improvements
Without using room corrections.
Al
Is there a posting or an article somewhere that describes the changes in the power supplies, analog stages, and digital stages of the new line versus the old line? All I've seen is a description of the newer DAC chip.
Nyal and I calibrated my speakers and integrated 2 mono subs today. We actually corrected the "greatest loudspeaker on earth!" 
. Actually it didn't need much correcting. But the improvement is real. Just the speaker correction makes everything more coherent and clear. The integration of the subs brings everything to a different level. The subs open up my music collection. I don't worry about how my levels are listening to big organ or electronica dance music. Nyal's attention to detail is unprecedented in my experience. I've never encountered any professional in high end audio that was so thoroughly prepared and could execute something like this without missing a step. I've heard DSP that sucked. I've never heard a sub integrate into a 2CH system without standing out like a sore thumb. Nyal's efforts using both DEQX and REW made the subs totally disappear. I think the problem with subs is that almost nobody goes through the effort to properly set the system up right. One needs the ability to delay main R/L and also be very proficient with REW to integrate subs into a 2CH system.
I have 4 profiles on the HDP-4. I still haven't got beyond profile 1.
DIRAC integrates very smoothly with the DEQX. I made 4 different filters, one for each DEQX profile.
Michael.
View attachment 14486 Nyal and I calibrated my speakers and integrated 2 mono subs today. We actually corrected the "greatest loudspeaker on earth!"
Nyal's attention to detail is unprecedented in my experience. I've never encountered any professional in high end audio that was so thoroughly prepared and could execute something like this without missing a step. I've heard DSP that sucked. I've never heard a sub integrate into a 2CH system without standing out like a sore thumb. Nyal's efforts using both DEQX and REW made the subs totally disappear. I think the problem with subs is that almost nobody goes through the effort to properly set the system up right. One needs the ability to delay main R/L and also be very proficient with REW to integrate subs into a 2CH system.
I have 4 profiles on the HDP-4. I still haven't got beyond profile 1.
DIRAC integrates very smoothly with the DEQX. I made 4 different filters, one for each DEQX profile.
Michael.
Michael, That's very interesting. I'm sure that with the DEQX one can set up the subs so that they are seamless. One can actually do it without DSP, BUT it takes a LOT more trial and error...never mind patience and time!
BTW, you have EXACTLY the same carpeting in your room as I have in mine...color and everything..Too much
The new DEQX processors....here's the back story
Back in the dawn of time (10 years ago+) DEQX released the PDC2.6, their first processor. It introduced their approach to DSP including the proprietary linear phase speaker correction and crossovers. Feedback was generally positive, with reviewers and customers thinking that the DSP was great but the physical implementation left some room for improvement. The word got out and after market modders started taking the unit and doing the typical op-amp, power supply and capacitor tweaks, which improved the sound quality. DEQX however got quite a few units back for repair that had developed problems from poorly executed mods. Of course they were curious as to why people were modding their units and found out that indeed some of these 'audiophile' tweaks did improve the sound. This led to the release of the previous generation units, the HDP-3 and the HDP-Express. These were based on the original PDC2.6 circuit boards but with upgraded parts and power supplies. These were good sounding units and received a few nice reviews online.
Fast forward a few years and DEQX released the HDP-4 and Express II, and a bit later on the MATE and PreMATE. These new processors are really the 2nd generation (the HDP-3/Express were a kind of gen 1.5) and incorporate a completely new main circuit board. There was a lot of attention paid to the design of the new boards including focus on circuit board layout, the op-amps used, digital and analog decoupling capacitors and power supplies. The new generation incorporate 32 bit Burr Brown DAC chips and the pathway between the DSP chips and DAC was upgraded to 32 bits. This allowed the volume control to be moved completely into the digital domain with no negative effects. All of the DEQXs incorporate coarse analog level adjustments with output voltages from 1-8V so that the processor can be properly matched with the power amplifiers and the digital volume control can always be run near the top of the range...though with 8 spare bits you have quite a bit of headroom anyway. The new generation also includes Crystals top ADC in case you want to feed it an analog source. There is also now a USB input based on the XMOS async USB chipset and the implementation is very good.
So if you are reading DEQX reviews online or people's comments LOOK at what generation they are using!!
It's worth knowing that the DEQX really is a multi-functional device. The main DSP functions are speaker correction, speaker crossover and room correction. You can just use it as a room correction processor, or just as a digital crossover. You don't have to use everything. It is also a digital pre-amp, as it can take digital signals and output analog. There is volume control and input switching.
The challenge with the DEQX is proper implementation, especially with the speaker correction. It really needs the help of a knowledgeable dealer to guide the end user through the speaker correction setup, and preferably one who understands acoustic measurements. The DEQX uses a quasi-anechoic measurement technique for speaker correction, in essence you cut out any reflections that reach the microphone. The longer time you have between the direct sound hitting the mic and the reflected sound the lower in frequency you can correct down to. A VERY common mistake is for people to include reflections thus corrupting the measurement, since you are correcting the impact of reflections on the measurement, not the speaker. A related and also VERY common mistake is to try and set the speaker correction to too low a frequency. The lower in frequency you want to correct the longer time window you need between the direct and reflected sound. The only real way to correct down to say 300Hz is to measure outside or in a large warehouse with the speaker off the ground. Anyone who buys a processor from me gets a free webinar on how to use the software and I focus particularly on the speaker correction piece as it trips most people up. If you hear a DEQX and don't like it chances are the speaker correction hasn't been setup properly. Feel free to ask the owner to contact me with their configuration file and I'll be happy to review it and if necessary point them in the right direction.
The new gen really does not need any mods doing to it. Anyone with a previous generation version who like it should demo a new one as the upgrade is substantial. I have a demo unit available should anyone want to try it (please PM).
Back in the dawn of time (10 years ago+) DEQX released the PDC2.6, their first processor. It introduced their approach to DSP including the proprietary linear phase speaker correction and crossovers. Feedback was generally positive, with reviewers and customers thinking that the DSP was great but the physical implementation left some room for improvement. The word got out and after market modders started taking the unit and doing the typical op-amp, power supply and capacitor tweaks, which improved the sound quality. DEQX however got quite a few units back for repair that had developed problems from poorly executed mods. Of course they were curious as to why people were modding their units and found out that indeed some of these 'audiophile' tweaks did improve the sound. This led to the release of the previous generation units, the HDP-3 and the HDP-Express. These were based on the original PDC2.6 circuit boards but with upgraded parts and power supplies. These were good sounding units and received a few nice reviews online.
Fast forward a few years and DEQX released the HDP-4 and Express II, and a bit later on the MATE and PreMATE. These new processors are really the 2nd generation (the HDP-3/Express were a kind of gen 1.5) and incorporate a completely new main circuit board. There was a lot of attention paid to the design of the new boards including focus on circuit board layout, the op-amps used, digital and analog decoupling capacitors and power supplies. The new generation incorporate 32 bit Burr Brown DAC chips and the pathway between the DSP chips and DAC was upgraded to 32 bits. This allowed the volume control to be moved completely into the digital domain with no negative effects. All of the DEQXs incorporate coarse analog level adjustments with output voltages from 1-8V so that the processor can be properly matched with the power amplifiers and the digital volume control can always be run near the top of the range...though with 8 spare bits you have quite a bit of headroom anyway. The new generation also includes Crystals top ADC in case you want to feed it an analog source. There is also now a USB input based on the XMOS async USB chipset and the implementation is very good.
So if you are reading DEQX reviews online or people's comments LOOK at what generation they are using!!
It's worth knowing that the DEQX really is a multi-functional device. The main DSP functions are speaker correction, speaker crossover and room correction. You can just use it as a room correction processor, or just as a digital crossover. You don't have to use everything. It is also a digital pre-amp, as it can take digital signals and output analog. There is volume control and input switching.
The challenge with the DEQX is proper implementation, especially with the speaker correction. It really needs the help of a knowledgeable dealer to guide the end user through the speaker correction setup, and preferably one who understands acoustic measurements. The DEQX uses a quasi-anechoic measurement technique for speaker correction, in essence you cut out any reflections that reach the microphone. The longer time you have between the direct sound hitting the mic and the reflected sound the lower in frequency you can correct down to. A VERY common mistake is for people to include reflections thus corrupting the measurement, since you are correcting the impact of reflections on the measurement, not the speaker. A related and also VERY common mistake is to try and set the speaker correction to too low a frequency. The lower in frequency you want to correct the longer time window you need between the direct and reflected sound. The only real way to correct down to say 300Hz is to measure outside or in a large warehouse with the speaker off the ground. Anyone who buys a processor from me gets a free webinar on how to use the software and I focus particularly on the speaker correction piece as it trips most people up. If you hear a DEQX and don't like it chances are the speaker correction hasn't been setup properly. Feel free to ask the owner to contact me with their configuration file and I'll be happy to review it and if necessary point them in the right direction.
The new gen really does not need any mods doing to it. Anyone with a previous generation version who like it should demo a new one as the upgrade is substantial. I have a demo unit available should anyone want to try it (please PM).
Nyal setup 4 different settings all with different varieties of speaker correction. One of them has no speaker correction. All four settings have the subs integrated so the only differences in the settings is the less aggressive to more aggressive speaker correction. I prefer the least aggressive speaker correction. However, there's a substantial improvement in image quality and localization, especially with cymbals, piano and brass. Loud electronica and rock music sounds better with more clarity. Finally, high resolution symphonic pieces from Reference Recordings are never heard before. Truly incredible.
One of the filters that I thought lost resolution a little was the recommended correction from DEQX. This is where leaning on a master like Nyal is so beneficial. Nyal set his own custom filter which is based on his expertise and knowledge of my listening preferences and speaker quality. Nyal's filter is totally transparent. There is no downside at all; only nice improvements.
Thanks again Nyal!
Michael.
One of the filters that I thought lost resolution a little was the recommended correction from DEQX. This is where leaning on a master like Nyal is so beneficial. Nyal set his own custom filter which is based on his expertise and knowledge of my listening preferences and speaker quality. Nyal's filter is totally transparent. There is no downside at all; only nice improvements.
Thanks again Nyal!
Michael.
Nyal, thanks for the version history. It appears they've really improved the sonics of their offering.
As an aside, or on a related note, when would you consider an alternative less automated product such as a Lake LM26 versus a DEQX, for crossover and correction (not for preamp) functionality alone? Both offer two in six out, with slopes, time delays, etc.
As an aside, or on a related note, when would you consider an alternative less automated product such as a Lake LM26 versus a DEQX, for crossover and correction (not for preamp) functionality alone? Both offer two in six out, with slopes, time delays, etc.
I have not had the pleasure of using the new Lab Gruppen Lake DSPs. The raised cosine EQ is very precise..."mathematically correct" as Keith Yates puts it...and apparently you can put cuts next to peaks with no strange effects.
As to sound quality, you would have to listen to each unit.
The DEQX speaker correction is proprietary, there is no one else doing it. It is a unique low latency FIR filter that corrects for both frequency and group delay.
I do use pro DSPs quite a bit, typically in home theater. One good application is for management of subwoofer arrays of 4 or more subs. I use Xilica, same brand as Legacy Audio use.
Obviously with a pro DSP like Lake or Xilica there is ZERO automation. You have to tell it exactly what you want it to do. The DEQX has software assisted speaker and room correction.
In addition to Lake and Xilica, I can recommend the DBX DriveRack series. The 4800 is as transparent as I've heard and extremely flexible. But not for the newbies, you must know what you are doing with these Pro speaker processors.
Nyal, thanks for the great write-up on the history of the DEQX line, I've been following them for the entire decade, and came close to purchasing the original 2.6 unit, but the lack of direct control and limited number of channels held me back.
I've recommended them to friends looking for a simpler path to achieve speaker and room correction. Nice to know they could also avail themselves of your expertise as well. As Michael notes, setup is critical to achieving good results.
Nyal, thanks for the great write-up on the history of the DEQX line, I've been following them for the entire decade, and came close to purchasing the original 2.6 unit, but the lack of direct control and limited number of channels held me back.
I've recommended them to friends looking for a simpler path to achieve speaker and room correction. Nice to know they could also avail themselves of your expertise as well. As Michael notes, setup is critical to achieving good results.
Nyal, not to take anything away from the older DEQX processors as I had an original DEQX Express for about a year-and-a-half and it was by-far the best upgrade that I've ever implemented into my system, but you are dead-on correct with the statement that the latest generation DEQX units are substantially better sounding than the previous. Amen. I'm speaking first-hand as I, probably like others, have previously wondered if the DEQX Express II was really that much better than the original Express.
The wondering is over. Now I've upgrade to the Express II, and using my same calibration file that I created on my original Express, I can easily say that there is an immediate noticeable overall improvement in the sound quality. As before, my DEQX is used as my main DAC and I feel that in this area, along with an improved analog section, is where the Express II really set's itself apart from the original Express. They both seem to do speaker correction, crossover function. and room correction equally as well, however, that's difficult to quantify. But moreover, I always thought that original Express had a very good sounding DAC in general, better than anything that I've ever used to date, and if it had any digital glare issues I sure didn't noticed it, but the Express II clearly has a much more fluid and natural sound with better dynamics than the original Express. Again, this is not to take anything away from the original Express since I could have easily lived with it for the foreseeable future, but now that I tried the Express II, I won't be going back.
At my house, listening is good these days after upgrading to the Express II. A new calibration file creation is planned using a recently acquired M23 kit. I guess that I will soon find out first hand if the M23 kit makes much of a difference over the standard calibration kit.
DEQX configuration: Bi-Amp with Stereo Subs /Speaker Correction/ Room Correction to 160Hz
Speakers: Apogee Duetta Signature (Graz MRT ribbons) - DEQX crossover at 1Khz 96db/oct
Subs: 2 x Rythmik/GR Research 12" - DEQX overlap crossover at (main to sub 80Hz 24db/oct) (sub to main 100Hz 24db/oct)
Amps: Jeff Rowland Model 5 (for MTR ribbons), Model 3 monos for main bass panels.
Forrest
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Thanks for the feedback Forrest, glad I convinced you to upgrade (and so are you from the sound of things!).
If you want me to look at your project file just let me know, I will be happy to do so. Most people try and set their correction filters to too low a frequency relative to the quality of the measurement that they took. DallasJustice's speakers we only corrected down to 1kHz using an in room measurement with the M23.
Nyal, I'm very pleased with the DEQX upgrade and I highly recommend to anyone who's on the fence about moving to the newest generation DEQX to stop waiting and make the move. I can assure them that there will be no regrets!
Also, I recently preformed a new calibration using the M23 and I immediately noticed a new level of clarity that I didn't realize I was missing all of this time. I now see that the M23/M30 kit is a must in order to bring out the best in the DEQX. For anyone who has the DEQX calibrated with the standard calibration kit and thinks that it sounds good now, you really need to buy or borrow an M23 or M30.
But moreover Nyal, I will soon be emailing you my DEQX configuration file since I would like to have your input on what I have. From my recent speaker measurements, I noted that the time-window between the initial impulse to the first reflection is about 12ms and that's with the microphone placed on-axis five-feet from the mid-range/tweeter ribbon in the center of a rather large room. I'm not quite sure how this relates to the lowest frequency that I should try to correct, but for now, I placed an arbitrary lower correction-limit of 500Hz, but I'm not really sure where this actually needs to be. Once you take a look at my file, you will see that I have another filter created with a lower correction limit of about 300Hz, but now after reading you post, I think that this is probably too low; however, this correction filter did sound very good and from this is where I made my initial listening observation on the M23 improvement stated above.
Also, I recently preformed a new calibration using the M23 and I immediately noticed a new level of clarity that I didn't realize I was missing all of this time. I now see that the M23/M30 kit is a must in order to bring out the best in the DEQX. For anyone who has the DEQX calibrated with the standard calibration kit and thinks that it sounds good now, you really need to buy or borrow an M23 or M30.
But moreover Nyal, I will soon be emailing you my DEQX configuration file since I would like to have your input on what I have. From my recent speaker measurements, I noted that the time-window between the initial impulse to the first reflection is about 12ms and that's with the microphone placed on-axis five-feet from the mid-range/tweeter ribbon in the center of a rather large room. I'm not quite sure how this relates to the lowest frequency that I should try to correct, but for now, I placed an arbitrary lower correction-limit of 500Hz, but I'm not really sure where this actually needs to be. Once you take a look at my file, you will see that I have another filter created with a lower correction limit of about 300Hz, but now after reading you post, I think that this is probably too low; however, this correction filter did sound very good and from this is where I made my initial listening observation on the M23 improvement stated above.
I am very happy with my DEQX HDP-4. I had to send my unit back for a repair; my fault. So, Nyal graciously allowed me to borrow his unit for a few weeks. When I got my new unit back, I noticed that it sounds a little better than Nyal's demo unit. Alan said they have made a few running improvements. I believe it! One of the things they have done is to use a new USB receiver. The newer version has a kernel called "Xcore." It's designed so that no 5v power is used from USB, not even the usual 5v to establish the "handshake" is used. I can totally turn off my 5v power on my sOTM USB card and it works beautifully.
I read Kal's column today in the new Sterwophile. I think he has a DEQX unit in for review. I look forward to his findings. I always enjoy his reviews. I hope he chose to use DIRAC for bass EQ instead of the old fashioned PEQ in the DEQX.
Michael.
I read Kal's column today in the new Sterwophile. I think he has a DEQX unit in for review. I look forward to his findings. I always enjoy his reviews. I hope he chose to use DIRAC for bass EQ instead of the old fashioned PEQ in the DEQX.
Michael.
What are your guys views on MiniDSP and Dspeaker.
I'm currently running 2 parallel correction/PEQ type systems for my Meridian DSP6000's and twin SVS subs and a 3rd KrK12's
FIR+ Peq using Acourate for the minidsp...considering getting the DIRAC verion??
and the self contained mixed Fir/IIR Dspeaker antimode 2.0
I can AB them back to back....they both sound different..I lean towards the miniDSP
I would like to hear Deqx..but being in South Africa , chances are nil...
I'm currently running 2 parallel correction/PEQ type systems for my Meridian DSP6000's and twin SVS subs and a 3rd KrK12's
FIR+ Peq using Acourate for the minidsp...considering getting the DIRAC verion??
and the self contained mixed Fir/IIR Dspeaker antimode 2.0
I can AB them back to back....they both sound different..I lean towards the miniDSP
I would like to hear Deqx..but being in South Africa , chances are nil...
Well folks,
being new to the forum and this topic, I'd like to steer attention back to DEQX.
I'm actually using one of the seemingly ancient PDC-2.6p, having bought a used unit 6 years ago. Just want to confirm that these old units really had room for improvement which I was able to implement by exchanging the main board with the "HD" version. Additionally though, I had a specialist replace the OPAs and later replaced the clock with a low jitter TENT oscillator plus a very stable power supply. This gave improved results with my 3-way activation of B&W Nautilus 804s, for which I linearized drivers, designed new x-over characteristics and optimised the step response with the PDC. Enough to say this worked excellent! A repurchase of a new unit was not necessary. Well, there's still potential with using a linear power supply and more, but a new unit is out of the question until the PDC just "dies".
Another, but not the least reason I post this is, that one more finding regarding the DEQX concept (which seems to not have greatly changed over the years really ) is the fact, that the unit's sound quality is depending on the quality of the incoming SPDIF or AES Signalto a significant extent! Means: If the dig. inputsignal is great, the unit sounds great. If input is "jittery" - you'll hear that (at least when comparing against a low jitter soure)!
So, what to do? Since almost 1.5 years I am now using a so called "reclocker" ahead of the DEQX AES or SPDIF input; it decodes the data from the incoming SPDIF or AES signal and modulates a new Signal using its own very stable Master Clock. The reclocking device is named Mutec MC-3+ and I can only strongly recommend to try this little device with your DEQX! It may relieve you from much higher investments !
If you are interested in what I have written, post your feedback or questions!
Cheers,
Winfried
being new to the forum and this topic, I'd like to steer attention back to DEQX.
I'm actually using one of the seemingly ancient PDC-2.6p, having bought a used unit 6 years ago. Just want to confirm that these old units really had room for improvement which I was able to implement by exchanging the main board with the "HD" version. Additionally though, I had a specialist replace the OPAs and later replaced the clock with a low jitter TENT oscillator plus a very stable power supply. This gave improved results with my 3-way activation of B&W Nautilus 804s, for which I linearized drivers, designed new x-over characteristics and optimised the step response with the PDC. Enough to say this worked excellent! A repurchase of a new unit was not necessary. Well, there's still potential with using a linear power supply and more, but a new unit is out of the question until the PDC just "dies".
Another, but not the least reason I post this is, that one more finding regarding the DEQX concept (which seems to not have greatly changed over the years really
) is the fact, that the unit's sound quality is depending on the quality of the incoming SPDIF or AES Signalto a significant extent! Means: If the dig. inputsignal is great, the unit sounds great. If input is "jittery" - you'll hear that (at least when comparing against a low jitter soure)! So, what to do? Since almost 1.5 years I am now using a so called "reclocker" ahead of the DEQX AES or SPDIF input; it decodes the data from the incoming SPDIF or AES signal and modulates a new Signal using its own very stable Master Clock. The reclocking device is named Mutec MC-3+ and I can only strongly recommend to try this little device with your DEQX! It may relieve you from much higher investments
!If you are interested in what I have written, post your feedback or questions!
Cheers,
Winfried
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