I am a DEQX user (HDP3 since mid 2012) and for me it has certainly been a game changer. It is not an easy product to set up and takes a great deal of research and learning to perfect. I now consider myself quite experienced. This was once I properly understood all the nuances of crossover slopes, phase, time alignment and room effects. What follows below is a simplified description of the procedure for using DEQX. The manual itself is lengthy and in many cases not easily comprehended (ie not difficult to get it wrong in several important aspects)
Originally I calibrated and used a pair of existing Shahinian Obelisks and the improvement compared to the sound I was familiar with was very dramatic. This was with the standard passive crossovers in place and blended to a pair of subs. By time-aligning these and with subtle room equalisation below 250hz, it was the first time that the crossover to the subs truly became seamless and all room effects disappeared (no exaggeration). I remember swearing out loud when I first got this, it has to be heard to believe it!
After a few months and fully appreciating what the DEQX could do, I decided to build a pair of Open Baffle speakers. Mid-sub crossovers are at 100hz (72db slopes), mid-treble at 3145hz (60db slopes). Extreme slopes allow individual amps and driver sets to operate within a narrow band and this creates very clean and dynamic transients
The beauty of DEQX is that you can calibrate these outdoors (raised ideally above grass, not a hard surface and no walls around so there are only very faint and unimportant reflections to corrupt the microphone reading) - the software creates a flat frequency response, which can be verified. Then when a mic is placed at the listening chair indoors, it compares with the original 'anecholic' result and time aligns all the drivers including phase at each frequency etc. All you then need to do is further manually time align the separately calibrated subs, if you use them. Very clever and effective - sitting in the sweet spot is holographic & 3D sounding. Performers 'hang' in space before you, realism way beyond anything I have heard in a hi-fi dealer demo, exhibition or, frankly anywhere else including some very expensive and otherwise impressive systems. My own speakers also manage to beat the Shahinians in every respect but I suspect this is more to do with 3 separate frequency bands being opimised for each driver set and very steep crossovers. The way this was described to me is like the latest military aircraft or Airbus. These are intrinsically unstable but sophisticated software allows them to fly. In the case of a fighter jet, often way beyond the realms of normal aerodynamics. I think that is what the DEQX algorithms do
Oh, and by the way...everything you do can be listened to using 4 presets to compare and changes made in real time whilst music is playing (including time alignment which I can only describe like turning the dial on a lens until suddenly everything falls into crystal clear focus, very useful)
DEQX is also an excellent preamp, completely neutral and very analogue sounding to my ears (I play a lot of vinyl) and also contains very good DACs (only bettered by a new Graham Slee product called the Majestic. I had previously used a Chord 64 and the DEQX DAC was much more musical, the Slee even more so)
I only caution someone borrowing and trying to set this up themselves in a short time. You may get 50-60% of what is possible but not appreciate what it can really do. When you do eventually dial everything in correctly, there really is no going back. I probably sound like I am preaching so sorry about that - I am 57 years old, have been fanatical about music all my adult life, am extremely fussy about realism and my loft is full of expensive but ultimately unrewarding hi-fi kit. If anything, after 2 years, I am more enthusiastic about DEQX that I was before
Originally I calibrated and used a pair of existing Shahinian Obelisks and the improvement compared to the sound I was familiar with was very dramatic. This was with the standard passive crossovers in place and blended to a pair of subs. By time-aligning these and with subtle room equalisation below 250hz, it was the first time that the crossover to the subs truly became seamless and all room effects disappeared (no exaggeration). I remember swearing out loud when I first got this, it has to be heard to believe it!
After a few months and fully appreciating what the DEQX could do, I decided to build a pair of Open Baffle speakers. Mid-sub crossovers are at 100hz (72db slopes), mid-treble at 3145hz (60db slopes). Extreme slopes allow individual amps and driver sets to operate within a narrow band and this creates very clean and dynamic transients
The beauty of DEQX is that you can calibrate these outdoors (raised ideally above grass, not a hard surface and no walls around so there are only very faint and unimportant reflections to corrupt the microphone reading) - the software creates a flat frequency response, which can be verified. Then when a mic is placed at the listening chair indoors, it compares with the original 'anecholic' result and time aligns all the drivers including phase at each frequency etc. All you then need to do is further manually time align the separately calibrated subs, if you use them. Very clever and effective - sitting in the sweet spot is holographic & 3D sounding. Performers 'hang' in space before you, realism way beyond anything I have heard in a hi-fi dealer demo, exhibition or, frankly anywhere else including some very expensive and otherwise impressive systems. My own speakers also manage to beat the Shahinians in every respect but I suspect this is more to do with 3 separate frequency bands being opimised for each driver set and very steep crossovers. The way this was described to me is like the latest military aircraft or Airbus. These are intrinsically unstable but sophisticated software allows them to fly. In the case of a fighter jet, often way beyond the realms of normal aerodynamics. I think that is what the DEQX algorithms do
Oh, and by the way...everything you do can be listened to using 4 presets to compare and changes made in real time whilst music is playing (including time alignment which I can only describe like turning the dial on a lens until suddenly everything falls into crystal clear focus, very useful)
DEQX is also an excellent preamp, completely neutral and very analogue sounding to my ears (I play a lot of vinyl) and also contains very good DACs (only bettered by a new Graham Slee product called the Majestic. I had previously used a Chord 64 and the DEQX DAC was much more musical, the Slee even more so)
I only caution someone borrowing and trying to set this up themselves in a short time. You may get 50-60% of what is possible but not appreciate what it can really do. When you do eventually dial everything in correctly, there really is no going back. I probably sound like I am preaching so sorry about that - I am 57 years old, have been fanatical about music all my adult life, am extremely fussy about realism and my loft is full of expensive but ultimately unrewarding hi-fi kit. If anything, after 2 years, I am more enthusiastic about DEQX that I was before