I have seen some posts on other forums claiming that DEQX kills low level signal and does not sound as transparent as well executed passive cross-over. Apparently those low level spatial clues are lost with DEQX and according to some it is better to have MF/HF crossover in a 3-way as passive. Anyone with experience in DEQX transparency?
I have been a DEQX user for several years now, the 2.6P. My opinion remains that once you go DSP active with a multi-way speaker's crossovers there is no going back. I find it almost shocking that writers “on other forums claiming that DEQX kills low level signal and does not sound as transparent as well executed passive cross-over” because my experience is the exact opposite. In my forty years as an audiophile transparent true to the source reproduction has always been among my highest priorities in music playback. Passive crossovers are basically placing a bunch of complexly nonlinear filter elements between amp and drivers vs. the mathematical precision of a DSP filter feeding amps directly connected to the drivers? And in the case of DEQX's implementation we also get the phase correction option that allowed me to finally get to my goal of the coherency of a full range electrostatic with the dynamics of multi-way moving coil driver based system.
As to why some would claim “DEQX kills low level signal and does not sound as transparent” I would speculate the following:
1. Analog bigots, their belief system is if its digital it cannot be as good as analog. My experience is one of the better sources I can use with my DEQX is one of my turntables+phono amp plugged into its analog inputs.
2. Poorly programed DEQX. The setup learning curve is steep and long, as is designing your own passive crossovers. A poorly programmed DEQX system will of course be a little or long way behind a competently designed passive cross-over system.
3. Lackluster digital source. I have observed my 2.6P when used with its digital inputs is rather sensitive to the quality of the S/PDIF or AES/EBU data source. For example there is a loss of transparency when using my Oppo BDP-80 Blu-Ray player compared to the lower jitter sources like a Denon DVP-2900 universal player and my computer USB-to-S/PDIF converter. This same mistake is so common in the countless LP vs. Digital debates that will always rage on the Internet. We often see OK but hardly top rank digital sources being trotted out as the straw men to 'prove' their argument that analog rules.
As to why some would claim “DEQX kills low level signal and does not sound as transparent” I would speculate the following:
1. Analog bigots, their belief system is if its digital it cannot be as good as analog. My experience is one of the better sources I can use with my DEQX is one of my turntables+phono amp plugged into its analog inputs.
2. Poorly programed DEQX. The setup learning curve is steep and long, as is designing your own passive crossovers. A poorly programmed DEQX system will of course be a little or long way behind a competently designed passive cross-over system.
3. Lackluster digital source. I have observed my 2.6P when used with its digital inputs is rather sensitive to the quality of the S/PDIF or AES/EBU data source. For example there is a loss of transparency when using my Oppo BDP-80 Blu-Ray player compared to the lower jitter sources like a Denon DVP-2900 universal player and my computer USB-to-S/PDIF converter. This same mistake is so common in the countless LP vs. Digital debates that will always rage on the Internet. We often see OK but hardly top rank digital sources being trotted out as the straw men to 'prove' their argument that analog rules.
There cannot be a universal answer to this question. It will depend on the particular implementation, your system and your ears. Can you reliably hear opamps in the signal path? Capacitors? Difference between dacs? If yes then maybe you won't find DEQX completely transparent. And this does not even take into account any potential issues in the digital domein.
Does it even matter? Audio is all about compromise and this is a good example where compromising may actually bring better sound. Or not.
For me it is clear that DEQX is an essential tool for anyone with serious interest in audio. It is also clear that good results cannot be had cheaply or easily, it's just not possible.
Hi SashaV,
I would say that’s true with the older version of the DEQX (PDC-2.6P), but the new HDP-3 pre-amp processor is a different story. They share the same functions and features but I think the PDC-2.6 sounded mediocre and definitely not high-end, but the HDP-3 on the other hand is a true high-end product where you don’t lose any detail or transparency. However its sound is very neutral to me.
To get the best sound with the DEQX, my advice is to use as low order slopes as possible e.g. 48db/oct it sounds better as the default 96db/oct or higher. Another important factor to get a success with the DEQX is that you have to treat the loudspeaker driver possibilities and weakness just as when building passive cross-overs. You still have to consider baffle step, baffle diffraction and off-axis behaviors when building the active cross-over as well as the passive. Look at this post to see what I mean. http://www.diyaudio.com/forums/mult...eqx-system-loudspeaker-measurement-study.html
Regards
/Göran
I would say that’s true with the older version of the DEQX (PDC-2.6P), but the new HDP-3 pre-amp processor is a different story. They share the same functions and features but I think the PDC-2.6 sounded mediocre and definitely not high-end, but the HDP-3 on the other hand is a true high-end product where you don’t lose any detail or transparency. However its sound is very neutral to me.
To get the best sound with the DEQX, my advice is to use as low order slopes as possible e.g. 48db/oct it sounds better as the default 96db/oct or higher. Another important factor to get a success with the DEQX is that you have to treat the loudspeaker driver possibilities and weakness just as when building passive cross-overs. You still have to consider baffle step, baffle diffraction and off-axis behaviors when building the active cross-over as well as the passive. Look at this post to see what I mean. http://www.diyaudio.com/forums/mult...eqx-system-loudspeaker-measurement-study.html
Regards
/Göran
I've had all three over the years. My first DEQX was a 2.6 then later the HDP3 and more recently I've had the opportunity to try the Express alongside the HDP3.
FWIW, the Express is based on the 2.6 with some tweaks such as different opamps and dac's. It still however has the SMPS that a lot of folks claim really held back the old 2.6.
My experiences have shown, for me, there's very little difference between the Express and HDP3 which is a downer considering the HDP3's price tag. The only thing I can really hear a definite difference between the two is the sound of my partners cry's about costs 😀
Seriously though if you can absolutely pick out a definite difference between these two then you've got better ears than my 32year old ones. I'd like to think I heared differences but being honest its tough. When I think I can hear one doing something better than the other I'll repeat the test again and the difference is questionable. If pushed I'd say the HDP3 can sound a bit more spacious on acoustic pieces and maybe the highs are smoother at times.
My advice is if your looking to buy a DEQX then absolutely go for the Express over the HDP3 if your even slightly worried about budget. However if you like a better built unit, the HDP3 gives you that at a price.
Regardless of this and going back to the original question I'd say once setup optimally any losses through digital conversion and processing are more than offset by the additional frequency and phase accuracy offered by the DEQX.
In short I'm secretly wishing passive would decline in popularity to allow for surge in digital filtering research and DSP related products but like the immortal vinyl I doubt that will happen in my lifetime 😀
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Goran its possible to use as low as 12dB/oct filters(not sure why there's no 6dB/oct option) with the DEQX but understandably these aren't FIR based. The minimum you use with those are as you stated - 48dB/oct. Personally I'm somewhat on the fence about high vs. low order filters. They can both sound terrible so you've got to take it on a per design basis. Generally I'd either go 2nd order if I have smooth extended and low distortion drivers and steep filters for almost everything else - I've found there's no real in-between there for the designs I've done. Its either all or as little as possible.
For crossing between mid and tweeter I’ve never used anything else but FIR filters. However between subwoofer and mid I’ve used conventional filter topologies.
Yes, I agree each system is unique and it pays off to extensively test different cross-over frequencies and slopes when building a speaker with the DEQX and fortunately it’s a very easy task to do with it. 🙂
In my experience, if you have well behaved drivers with no or little cone break-ups they sound better with low order slopes. If you have e.g. metal cone drivers with nasty cone break-ups you must obviously use steeper slopes. To be honest it’s not a huge difference in sound quality between 48db/oct, 96db/oct or >96db/oct, but it’s noticeable. I think the DEQX Team officially recommending slopes between 48-60db/oct.
For best results with the DEQX, avoid drivers with nasty cone break-ups. 😉
ShinOBIWAN, have you tested hybrid filters with the DEQX, a hybrid filter where perhaps you have some contour shaping passive filters, but where the final tuning is done with the DEQX?
/Goran
Interesting advice. Actually a very interesting thread.
(Me a DEQX user from the beginning but have only used it with two different speakers: one a DIY a semi-SOTA system using the large B&G 75 planars, IB subwoofers and scan speak midwoofers and the other a small modestly priced conventional bookshelf system, but in both cases basically just so smitten with the results to the point I have never really spent time tweaking).
I always gathered that one of the the chief strengths of the DEQX is its ability to deal with out of band nasties from metal divers and milk the lowest frequencies out of any given driver cuz of of the steep XO's. Certainly took care of the cavity resonance at 5k that is a bit of a wart on the B&G planars. Also thought that the NHT XD-1 using the SEAS mag woofer sounded pretty darn good.
In any event I am delighted to find some active DEQX users as the forum on yahoo is dead. In the process of building some monitor style speakers and looking for some advice.
Does it have to be black and white?
Ponder for a moment that passives and DSPs can both produce excellent results.
The skilled designer/user knows when to pick the most suitable for that specific implementation.
If I can get a simple passive two-way crossover good enough I'm having a hard time seeing an expensive dsp as a worthwile upgrade considering you have to have a stack of amplifiers to go with it.
Using a passive x-over you only need one amp and you can go for a really good one without having to morgage the house.
With a passive x-over you only need one dac, with multichannel dsp you ned one for each (L/R) channel and the total number depends on the drivers you are using.
DSP can be awsome but it's not necessarey a cheap and easy road to nirvana.
Until a moth ago I was dead set on going the digital rout myself. Once I started reading I began to become more and more interested in passive design.
It's an art and I've always liked a challenge. 🙂
So, do a lot of reading about the pros and cons, then decide for yourself depending on your needs.
Cheers
Ponder for a moment that passives and DSPs can both produce excellent results.
The skilled designer/user knows when to pick the most suitable for that specific implementation.
If I can get a simple passive two-way crossover good enough I'm having a hard time seeing an expensive dsp as a worthwile upgrade considering you have to have a stack of amplifiers to go with it.
Using a passive x-over you only need one amp and you can go for a really good one without having to morgage the house.
With a passive x-over you only need one dac, with multichannel dsp you ned one for each (L/R) channel and the total number depends on the drivers you are using.
DSP can be awsome but it's not necessarey a cheap and easy road to nirvana.
Until a moth ago I was dead set on going the digital rout myself. Once I started reading I began to become more and more interested in passive design.
It's an art and I've always liked a challenge. 🙂
So, do a lot of reading about the pros and cons, then decide for yourself depending on your needs.
Cheers
DEQX support seams to be almost completely dead. I have had a PDC2.6since 2002, later switched to the 2.6P preamp version which was later on upgraded to 3.0. This was the latest I will ever spent on DEQX. Since about 10 years they have promised features that never came to light. The latest software for the 2.6 and 3.0 version is in beta for years now. There is still no ofrficial release for 96kHZ support. They promised real room correction. Never came. Room correction is no more then terrible executed automated EQ. They promised many many things but it never ever happened. I don't mind paying a lot of money on a software based piece of equipment as long as they keep up their promises. It's the software development you pay for but there has not been any development in the last 5 years or so. In fact, pretty much nothing really changed in 10 years. I'm highly disappointed in their support. There used to be a forum where some people made some good suggestions for new features to make it a much better product seperate LR EQ, seperate EQ for subwoofer, shelving filters, smaller delay steps, timing error correction for room correction to name a few. They did nothing with it Software development is on a dead end at DEQX. If I had to buy a new crossover I would go and look somewhere else. DEQX is getting obsolete, other are more flexible nowadays and have better support for the DIY community.
DEQX support is well and truly alive!
DEQX still have full support for all of our products and recently expanded beyond email and phone support with the introduction of the on-line DEQXpert installation and/or training service.
DEQX’s last beta software release was in 2008. Since then we’ve issued release software v2.70 for the oldest model PDC-2.6 & the HDP-3. As with the last beta version, this fully supported 96k filters and processing. Release version v2.93 for the current processor models including the HDP-4 supports 24/192 inputs and asynchronous processing from 44.1– 96k. In PDC-2.6 to HDP3 products sample-rate, clocking and related issues hardware (not software) limited.
In early days of DEQX’s development of firmware, software and hardware the ‘forum’ was for in-house ‘beta testing’ by invitation where early adopters shared information, made suggestions and report bugs. The forum was closed in 2008 when software was stable and public forums like DIY-audio were better suited to discuss DEQX and other products with more people.
DEQX’s main focus has always been speaker improvement where, at least in affordable systems, the most serious audio degradation occurs. ‘Room correction’ and preference settings use parametric EQ so users can manipulate bands graphically over room measurements in real-time with multiband minimum-phase resolution. This allows the real-world effects of frequency, gain & Q adjustments to be monitored in real-time rather than setting theoretically desirable target curves and hoping for the best. The ‘auto set EQ’ mentioned provides only a minimalist starting point by placing multiple EQ bands where needed before tweaking to taste, when four profiles can be saved and instantly compared.
More detailed FIR style Room Correction is also available, and particularly useful in non-symmetric rooms where calibration of left and right bass is needed separately, as the paraEQ operates globally.
Making good anechoic measurements is more complex than room measurements. This is why we introduced the DEQXpert on-line installation. This also deals independently with left & right channels whereas parametrics used for room EQ and preference settings operate globally.
As you noted the DEQX offers active linear-phase crossover with impulse response correction (time and freq domain) and is still today almost the only non-computer based product of its kind. While software can provide some small sonic upgrades we have listened to our greater user base and completed major hardware redesign to enhance the performance of our products. The HDP-4, Express 11, Mate and PreMate have received nothing but glowing reviews and praise from DEQX owners who have upgraded (see http://www.deqx.com/reviews.php
Another feature touched upon was inability to provide fine time alignment adjustment. At least for tweeter/mid crossover, driver time alignment is automated to sample accuracy based on the measured acoustic phase on-axis at the crossover frequencies. For mid-bass crossovers manual adjustments to 0.01ms can be set manually based on impulse-response delays between main and bass speakers, usually measured at the listening position.
We hope this helps clarify some of the issues mentioned here. We may not monitor forum posts so for more information please contact support@deqx.com where we always welcome comments and suggestions.
David Higginbottom
Director Business Development
DEQX Pty Ltd
DEQX still have full support for all of our products and recently expanded beyond email and phone support with the introduction of the on-line DEQXpert installation and/or training service.
DEQX’s last beta software release was in 2008. Since then we’ve issued release software v2.70 for the oldest model PDC-2.6 & the HDP-3. As with the last beta version, this fully supported 96k filters and processing. Release version v2.93 for the current processor models including the HDP-4 supports 24/192 inputs and asynchronous processing from 44.1– 96k. In PDC-2.6 to HDP3 products sample-rate, clocking and related issues hardware (not software) limited.
In early days of DEQX’s development of firmware, software and hardware the ‘forum’ was for in-house ‘beta testing’ by invitation where early adopters shared information, made suggestions and report bugs. The forum was closed in 2008 when software was stable and public forums like DIY-audio were better suited to discuss DEQX and other products with more people.
DEQX’s main focus has always been speaker improvement where, at least in affordable systems, the most serious audio degradation occurs. ‘Room correction’ and preference settings use parametric EQ so users can manipulate bands graphically over room measurements in real-time with multiband minimum-phase resolution. This allows the real-world effects of frequency, gain & Q adjustments to be monitored in real-time rather than setting theoretically desirable target curves and hoping for the best. The ‘auto set EQ’ mentioned provides only a minimalist starting point by placing multiple EQ bands where needed before tweaking to taste, when four profiles can be saved and instantly compared.
More detailed FIR style Room Correction is also available, and particularly useful in non-symmetric rooms where calibration of left and right bass is needed separately, as the paraEQ operates globally.
Making good anechoic measurements is more complex than room measurements. This is why we introduced the DEQXpert on-line installation. This also deals independently with left & right channels whereas parametrics used for room EQ and preference settings operate globally.
As you noted the DEQX offers active linear-phase crossover with impulse response correction (time and freq domain) and is still today almost the only non-computer based product of its kind. While software can provide some small sonic upgrades we have listened to our greater user base and completed major hardware redesign to enhance the performance of our products. The HDP-4, Express 11, Mate and PreMate have received nothing but glowing reviews and praise from DEQX owners who have upgraded (see http://www.deqx.com/reviews.php
Another feature touched upon was inability to provide fine time alignment adjustment. At least for tweeter/mid crossover, driver time alignment is automated to sample accuracy based on the measured acoustic phase on-axis at the crossover frequencies. For mid-bass crossovers manual adjustments to 0.01ms can be set manually based on impulse-response delays between main and bass speakers, usually measured at the listening position.
We hope this helps clarify some of the issues mentioned here. We may not monitor forum posts so for more information please contact support@deqx.com where we always welcome comments and suggestions.
David Higginbottom
Director Business Development
DEQX Pty Ltd
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