Is DEQX a game changer?

Just finished an hour and a half fine tuning session with Larry, the DEQXPert. At his suggestion, I move my listening couch back a little and he re-tuned my system. Definitely better. He also gave me a setting option with a slight bass boost, which is kinda nice.

I'm still a DEQX believer. I'm two thumbs up for the DEQX.

No way I could have made the fine tuning adjustments by myself.

Cheers.

BIF

?? DIRAC handles 24/192 just fine if your computer is up to the task.

Kal, does the DIRAC handle 24/192 better?

^O.K., thanks for the clarification.

I think you may be misinterpreting a paraphrase of my published statements. If I may, I would edit your interpretation to say: "It seems to me that the user friendliness AND COST of the DIRAC was a major reason Stereophile seemed to RECOMMEND IT OVER the DEQX."

Dirac is cheaper and easier to use but not as capable as DEQX. If DEQX made a multichannel version, I'd use it.

^"The best 67 audio components of 2014"

Where did you see that "Stereophile seemed to prefer it {Dirac} to the DEQX?'

It seems to me that the user friendliness of the DIRAC was a major reason Stereophile seemed to prefer it to the DEQX. As far as I can tell, the DIRAC might not offer the advantages of custom x-overs that the DEQX offers. For those not interested in by passing their existing x-overs, or the expense of additional amplification, there could be substantial cost savings.

Ozzy, I think your logic is sensible and will apply to many.
It costs (next to) nothing to 'tinker' with ideas for room treatments and most will accept the musical happiness they can obtain thereby (and I have experienced huge improvements that way); and of course we're all well aware of the potential for significant change due to the staggeringly quick evolution of digital and communication (transmission) technology. But, this conversation confirms the units do seem to offer previously unavailable, perhaps unimaginable, options to a serious music lover who wants more 'you are here' feeling. We live in exciting times don't we.

Bifwynne, Thank
you for your reply. I really do enjoy the way my system sounds. So, I guess for now I will wait until Deqx comes out with a version that an average person can adjust.

Ozzy, let me just add one comment that is really obvious but important to emphasize. Even one owns $200,000 Wilson Alexandria speakers, if the room is tugging the FR of the speakers all over the place, I can't see how it is possible to appreciate what your speakers can do unless something gives.

That might mean serious room treatments and/or a DEQX or similar room EQ device to tame the room acoustics. Let's face it, most of us don't listen to our rigs in an anechoic chamber. So, IMO, this is a very important consideration.

1. Use digital in/outs but the digital bottleneck is unavoidable.

Ozzy,

I'll take a crack at Questions 2 and 3.

Q-2: Maybe. It depends on the significance of the room interactions with your speakers. My listening room/basement is acoustically terrible. I had to move a lot of stuff around. But the results were well worth the effort.

But look at it from another angle. If your room is really screwing up the frequency response of your speakers at the listening position, and the interactions are so significant that the DEQX will only partially tame the problem, you are losing out on a lot of potential improvement.

In my case, imaging was smeared because, in effect, I was listening to two different speakers. The FR of the L and R speakers were way off. Having said all that, you really won't know what (if anything) needs to be done until the DEQX runs its sweeps and the room effects are measured.

Q-3: If you're a techie, you might be able to slug your way through the set up. Andrew (Drewan77) has become quite facile doing his own set ups. But in my case, I wouldn't touch it. I worked out a comfortable fee arrangement where the DEQXpert did everything over the internet with my PC. Set up took over 3 hours!! And btw, he only "tamed" my speakers. They are NOT perfectly matched or flat. The DEQXpert made judgments based on his technical skill and empirical experiences.

The Problems I have with the DEQX unit as I seem to understand.

1. I would prefer to use my PS Direct Stream Dac over the DEQX (24/96 limited) Dac. So, which Deqx unit would be best for that application?

2. I have 215lb speakers that I would prefer to keep in there present place. So, can I expect good results with the Deqx unit to calibrate my speakers as they sit?

3. Is this unit so complicated that I will need an "expert" to set it up?

I have found that the DEQX does not degrade the signal from a vinyl source.

Roscoeiii: Very curious to hear more about others' use of the analog input into the DEQX. As a vinyl guy, I worry about losing some of that analog magic....

I also prefer to listen to vinyl and can confirm that DEQX has only enhanced 'that analog magic'. The TT phono stage is connected directly into the RCA unbalanced analogue sockets. All my other devices are input from a preamp via the balanced analogue XLR connections and I also use the analogue volume control feature. There is certainly no digital glare

The benefits of removing room/speaker influences are astonishing. As an analogy, some years ago I took an eye test because I felt my night driving vision had deteriorated a little but I thought everything was OK the rest of the time. When I first tried the glasses, I was amazed how everything was suddenly pin-sharp even though I hadn't noticed it over the preceding years and didn't even realise

For me that's exactly what DEQX does - "spectacles for my ears"!

Bombaywalla,

You are right, we did have a lengthy discussion with Roy on the topic, and he did say that about processors...including DEQX. But my take was his answer was based on speculation on his part as to how these devices work. He didn't come through as if he had actually tried any of these. He is a believer on time-alignment and has developed analog XO to do that at all frequencies, and I think he believes measurements cannot deliver the same and the differences are significant enough. But from people's experiences here with DEQX and elsewhere with Acourate, users are very happy compared to their situation pre-digital device.

I've been in touch with a guy who has a very expensive system with YG speakers, etc, and used to own a TotalDAC D1, which he replaced with a DEQX HDP-4 and was super happy about the change and couldn't talk highly enough about it. He now replaced it with a Lynx Hilo and Acourate and now he can't talk highly enough about that setup. I am by no means suggesting the latter approach is better than the DEQX, but his experience shows good results can be achieved either way. And the multiple good reports also suggest measurement-based approaches indeed work, even if suboptimal vs Roy's approach.

BTW, I've been slow to implement any of these for several reasons. I was considering an exaSound e28 (8-channel DAC) and bought a used e22 (2-channel) to try out and concluded the e28 would not be a good path. Plus I live in a country where getting all of these things is super complicated - takes a lot of time.

Nevertheless been enjoying this thread and the good experiences shared here.

Cheers

11-22-14: Lewinskih01
Al, since I'm posting I wanted to throw in a comment directed to an earlier post of yours. In Acourate, the treble, mids and bass need to be in different channels for the software to be able to time align them. I believe the setup you were planning with DEqX had just one channel for right and one one for left (from a digital processing point of view). I would double check DEQX would allow you to time align the drivers in such a setup.

Thanks, Lewinski. Your interpretation of my intended application is correct. And the very question you raise had in fact occurred to me some time ago. But the writeups at the DEQX site make very clear, as I interpret them, that in addition to being able to time align independently powered drivers, their present-generation processors can also restore time coherence (to a good approximation) within and throughout however much of the audible spectrum can be reproduced by whatever each of its output channels is providing a signal to. Otherwise, for one thing, that processing would be worthless with respect to correcting the coherence issues of in-speaker passive crossover networks that are higher than first order (6 db/octave).

Also, I don't doubt that were I all mixed up about that, Drewan, Psag, et al, would have pointed that out to me when I described my intended system configuration.

Best regards,
-- Al

Lewinskih01 is partially correct if Almarg is only using a pair of full range speakers. There will be no opportunity to manually adjust time alignment but DEQX will still take care of this

The processor will automatically phase & time align what it hears during the measurement and calibration processes but there can be no manual time alignment as there would be when using 6 channels or 2-way plus sub(s)

Very curious to hear more about others' use of the analog input into the DEQX. As a vinyl guy, I worry about losing some of that analog magic, though I recognize that the benefit of the speaker and room correction could very well outweigh the possible loss of sound quality that comes from A-D-A conversion.

Lewinskih01, i thought that we had a lengthy debate on Acourate in the "Sloped Baffle" thread with Roy Johnson & others & we (mainly Roy J) concluded that Acourate did not have the Math right to correctly check the impulse response of the speaker & correct its response? I'm pretty sure that you were part of that discussion. Despite this did you still decide to use Acourate? thanks.

Unsound,

You are right: certain software packages can do that. I'm not sure Dirac can, though. I believe it is focused on digital room correction only.

Acourate (another software package) can do digital room correction, and digital crossovers and allows to time align the different channels, and also linearize the drivers. In fact it's in my plans to use Acourate in my server and feed a multichannel DAC to drive two powered subwoofers and three stereo amps driving tweeter/midrange/woofer, and no XO on the speakers.

My advantage in taking this path is I have disposed of other sources and now just use a very optimized PC (optimized in hardware and software). Clearly not the same as using a laptop either.

Like Bifwynne, I'm having a hard time of letting go of my beloved tube preamp - Lamm LL2 in my case.

For those interested I suggest reading a couple of articles over at computeraudiophile.com by member Mitchco, who's very knowledgeable:
An intro to Acourate
Time alignment walkthrough

I follow this thread with much interest as I see the DEQX as able to do the same things, in a simpler way albeit more expensive.

Al, since I'm posting I wanted to throw in a comment directed to an earlier post of yours. In Acourate, the treble, mids and bass need to be in different channels for the software to be able to time align them. I believe the setup you were planning with DEqX had just one channel for right and one one for left (from a digital processing point of view). I would double check DEQX would allow you to time align the drivers in such a setup.

Thanks Al. Interesting point. Admittedly, I have an irrational bias (pun) to using the DEQX in analogue mode. That is, my CDP is hooked up to my Ref 5 SE preamp, and the DEQX is inserted in between the Ref 5 and my amp. I suppose I can't bear the thought that my Ref 5 is no longer needed.

Al ... I'll check the sound playback on a with and without basis. As far as ground loops are concerned ... nothing I can discern at this point.

Now ... the cross talk point may be relevant. At times, it seems that my CDP is playing in "mono'ish" mode. I wonder .... uuhhm.

Cheers,

Bruce

11-22-14: Bifwynne
... my "redbook" ARC Ref CD-8 CDP is hooked up to the PreMATE via two modalities: (1) analogue through my ARC Ref 5 SE preamp in "normal" analogue fashion and (2) digitally via the digital output of CD-8 directly into the PreMate's XLR input. In the later case, my CDP is acting merely as a transport and the PreMATE is the DAC.

Hi Bruce,

At the risk of adding further complication to an already very complicated assessment and adjustment process, I'll mention that I would keep in mind the possibility that the sonics you hear from the analog and the digital outputs of your CDP MIGHT be affected, at least slightly, by having both of those outputs connected into your system simultaneously.

Having multiple paths in the system through which signal return (ground) currents can flow, some of them associated with digital circuitry and some with analog circuitry, raises a caution flag in my mind about the possibility of one affecting the other, at least slightly. And also the possibility of issues arising from ground loops involving those signal return connections and the AC safety ground wiring of the three components. And, finally, the possibility of low-level "crosstalk" within the DEQX between the digital and analog inputs, if and when signals are provided to both at the same time.

Best,
-- Al

Unsound ... not sure if this post is responsive to what you just posted. In my case, I am using the DEQX principally for its time alignment and room EQ functionalities in analogue mode. And as many have already posted, the DEQX works very well in these functions.

Yes ... the DEQX PreMATE has an onboard DAC. In fact, as I posted somewhere above, my "redbook" ARC Ref CD-8 CDP is hooked up to the PreMATE via two modalities: (1) analogue through my ARC Ref 5 SE preamp in "normal" analogue fashion and (2) digitally via the digital output of CD-8 directly into the PreMate's XLR input. In the later case, my CDP is acting merely as a transport and the PreMATE is the DAC.

I have not come to a unequivocal view as yet whether I prefer the analogue or digital hook up for my CD-8. The ARC CD-8's onboard DAC is based on a Burr Brown 1792 (I think) chip and is very good. The DEQX's DAC is based on a Burr Brown 1795 (I think) chip and is also very good and sounds very similar to the CD-8 albeit a little different. Just not sure which I like better.

My point is that while the DEQX PreMATE can do a more than just time alignment and room EQ, the foregoing functionalities are its signature

Unsound - yes programmes like Dirac can achieve a similar result but require a computer to be running the system whereas DEQX is an elegant 'hi-fi, one box' solution. Because everything can be automated via widgets, it is also quite logical & easy once you get the hang of it

I would be nervous about adding a potentially 'noisy' laptop or PC into my high end system when listening. I connect my Macbook (running a windows emulator) during setup or modifications, then unplug once I have everything sounding the way I want it. The best DEQX products also contain a linear power supply and are very transparent

Though I myself find a stand alone dedicated device like the DEQX much more appealing than software loaded onto a computer, it is interesting that though Stereophile gave the DEQX an enthusiastic review, in the very same edition they gave a preferential nod to the far less expensive DIRAC software program (that also seems to be able to better handle 24/192).

Hi Bruce. If you mailed me your configuration file I could have a look at how it's been set up (its a .mzd file stored in the DEQX folder on your PC/Laptop). This would allow me to see all your measurements and how Larry set it up. If the file is too large we could use Dropbox or similar (my working config file is 9MB but this has measurements for 4 sets of speakers and 3 types of Sub, yours should be much simpler)

This doesn't mean I would change anything unless you wanted me to but if you then asked questions about any of the features, I could modify the file, save another version and send it back to you to load and try out
Cheers
Andrew

Andrew (Drewan77) --- been following the last several posts. As you know, I just bought the PreMATE. Larry, the DEQXpert, set it up. Interestingly, he cut the self powered sub woofer off at 120 Hz and let the speakers' passive woofers take it from there until they crossed over to mid-driver at 200 or so Hz.

Based on Larry's measurements, my sub woofer is pretty flat down to about 13 Hz, which is pretty low. Kinda weird, but the speaker's woofers are covering about 80 to 100 Hz of bandwidth. So, the bottom line here is that the heavy bass lifting is being handled by the sub woofer.

There is an added plus ... namely that it takes "pressure" to delivery power off my amp and shifts it to the subwoofer, which has a built-in amp rated at 3400 watts max-Q. I've tripped my circuit breakers plenty of times.

All-in-all, I think my speakers sound better than before. When I cut the PreMATE out of the circuit (P0 button), the sound presentation is muddy and imaging is smeared. When engaged, sharper imaging, better transients, nicer sounding musical presentation.

I would like to explore and play with the PreMATE's considerable functionalities. Problem is that the owner's manual is not very user-friendly and is accessible only on-line or off a disc. Plus, I am not very tech or computer wise.

Sure wish I could spend some more time with Larry the DEQXpert.

Bruce

The comment to use steep crossover slopes is for those that can bi amp that still have their crossovers in place.... sorry for any confusion.

Hi Al, yep, Oh, absolutely. You can increase delay, but you cannot decrease the delay. If any designer ever over compensated with Baffle step compensation or match pad, you cannot remove that resistance or speed up the passive parts inside. On the other hand, you can add delay electronically. What I have loved reading about the DEQX is that once mic'd, it will automatically adjust time delay and help eq... This is a tremendous benefit. I would also suggest that you take your current crossover points and try taking a listen at very steep slopes, say 48db per octave. On some speakers that alone can make things more coherent and easy enough to reverse if it doesn't work out. Good Luck with it, Let us know how you like it, Tim

Tim, Andrew, Denis, thanks for the excellent inputs. Points taken.

11-19-14: Timlub
When building speakers, we time drivers [that] are not time aligned on the frontal plane by adding padding/baffle step compensation to change the delivery of the tweeter and mid hitting your ear at the same time. This is built into the crossover. An External device cannot change that as far as true timing speed is concerned.

Hi Tim,

You may already be aware of this, but just to be sure the DEQX processing divides the spectrum into thousands of segments, adjusting the delays of each of them such that time coherence is attained even in the presence of a passive crossover within the speaker that is higher than first order, which would normally make time coherence impossible. See the graph and the references in the text to group delay in this writeup at the DEQX site, as well as the HDP-4 brochure and their FAQ writeups.

Best regards,
-- Al

Good to read your comments Denis and you have reminded me of an important aspect that Almarg may want to consider

A full range speaker such as the Ulysses that he describes will benefit from DEQX (automated) phase and time alignment, however the larger drivers will still need to handle all lower frequencies up to the passive crossover point

If you can reduce the number of frequencies a driver has to cope with and use a steep crossover, each cone has less work to do to reproduce the remaining range cleanly

Adding a sub to such a speaker gives the facility to remove deep bass frequencies via DEQX (in 'our' case below 100hz) which means the larger drivers will only concentrate on mid-bass upwards and this makes a significant difference to transient attack and overall cleanness of the sound. It is exactly what I originally did with my old Obelisks ad still do with the OBs

Your points about voicing are very valid and yes crossover frequencies and slopes can be tested via the presets as part of the configuration process until you arrive at your optimal voicing. For all the uninitated reading this - it means your system can sound exactly how you want it, in my case clean fast, dynamic & punchy right down to a measured -2dB at 16hz

Timlub, whilst you are correct and I have used DEQX in all the configurations you mention, even on a speaker containing a passive crossover, the sense of reality and coherence is very impressive. However Bi-amped with Subs or Tri-amped is at a whole new level and I will never go back

Hi Al,
Thanks for the reply. When building speakers, we time drivers are not time aligned on the frontal plane by adding padding/baffle step compensation to change the delivery of the tweeter and mid hitting your ear at the same time. This is built into the crossover. An External device cannot change that as far as true timing speed is concerned. Using a 2 way as an example: When bi amping, you can change the delay of the response of any driver to properly align when the response of each driver will hit the ear.
What the DEQX would have to do is send a delay of given frequencies of one driver or the other to compensate for the work that has been done in the crossover....
My point was more that by completely removing the crossover, you should gain the attack, leading edge info and detail that hundreds of foot of copper coil can diminish in a crossover. There should be no comparison of the speaker with a crossover vs without. Any multi driver speaker with a DEQX with proper delay and room compensations tailored and the passive crossover removed should be a whole new world compared to the same speaker with the crossover left in tact. Theoretically, you should be able to take any 2 or 3 way with quality drivers and customize the DEQX settings (eq out the bumps, bring up the dips, time align, eq for room) to be a world class speaker system. Yes, it can certainly help a speaker without removing the crossover, but even with the best speaker systems available, if the DEQX is biamped (2way) there should be no comparison.

Yes Al, you can be confident that your Ulysses will sound so much better with the HDP-4. Unmodified Shahinian Obelisks were my first foray with DEQX and I was amazed at the improvement in clarity and realism it brought to them

Bi & tri-amping is the ultimate but nevertheless this manages to transform literally every type of speaker & room I have tried

You have an enjoyable time ahead - just be prepare to lose the rest of your life to the music :)

11-19-14: Almarg
John, LOL! :-) I wonder what the "three amigos" would have to say about that. (To the others, that's an inside joke; don't ask). Come to think of it, though, I don't want to know :-)

I'm glad someone got it Al, I knew I could count on you. ;^)

I just have to laugh at the 2014 marketing phrase of the year: Game Changer.
It seems like everything out there these days is a game changer.....sigh.

Cheers,
John

Andrew (Drewan77), awesome! Thanks!

11-19-14: Timlub
Hi Guys, I have read several post, but not near all, this may have been addressed. I have no doubt that the DEQX could be a game changer, but it would require Biamping, triamping etc.

Tim, my hope and expectation, based on the inputs from several DEQX users in this thread, and on Kal's review, and on the comments on time coherence by Bombaywalla and others in this thread and the recent "sloped baffle" thread, is that that is not the case. My Daedalus Ulysses speakers are not even biwirable or biampable, having just a single pair of terminals. Designer Lou Hinkley doesn't want users doing those things, and in the process risking introducing compromises to what he has worked hard to achieve. I simply hope and expect that the sophisticated time alignment and room correction features of the DEQX, and possibly a little bit of additional equalization here and there, will enhance the already good sound I am getting from them to a significant degree. As well as perhaps also providing an upgrade to my preamp, and maybe even to the DAC and analog sections of my CDP.

As Kal said in the conclusion of his review:

It made my very good speakers undeniably better, smoother and cleaner, and endowed them with a bigger soundstage. It mad dense complicated music easier to resolve, and all music more of a joy to hear.

Best of luck with the Mini-DSP, btw. I am not familiar with it.

BTW, I'll add to my previous comments about the system configuration in which I intend to use the DEQX that I do not envision adding subs in the foreseeable future. A majority of Ulysses owners do not use them with subs, although Lou offers what is apparently quite a good (and somewhat expensive) passive sub that is designed to mate with them. But the Ulysses are rated down to 28 Hz +/-2 db, which is good enough for me. And that rating seems consistent with evaluations I have performed using test tones, as well as listening to well recorded organ music, etc.

John, LOL! :-) I wonder what the "three amigos" would have to say about that. (To the others, that's an inside joke; don't ask). Come to think of it, though, I don't want to know :-)

Best regards,
-- Al

Right John. Going in circles.

As a DEQX happy owner, I've been following this this discussion with great interest.

I have been in DIY speaker building for more than 40 years (not getting any younger...). I experimented many things over the years, and yes, I can strongly affirm that DEQX is a game changer for me.

Achieving the "perfect" passive crossover is a mission impossible, at least for DIYers, which are not necessarily equipped to conduct all the required tests and moreover, because of the numerous technical limitations (especially phasing) that good old capacitors and inductors introduces by their electrical nature.

I moved to analog active crossovers and tri-amping 15 years ago and at that time, it was clear I would never go back to passive crossovers and single amp. I moved to the 3rd generation of audio filtering: digital. I bought the DEQX ExpressII and more than one year later, I can say it's the greatest toy I ever bought to myself! I would have never thought that the improvement would reach that level. It is a great pleasure to listen to commercial speakers that sells more than 10 times the price I paid for my drivers and doesn't "beat" my homemade speakers (hum...I may not be fully objective...) Therefore, I can now say that I would never go back to analog active filtering (2nd generation)... Imagine how far I am from the first generation of filtering...

I see no merit in commenting my own experience with my DEQX since it would be a copy of the excellent description Drewan77 made and as you can see, I fully share his enthusiam.

As a speaker builder, I'm having so much fun calibrating the speakers using a mouse and a keybord ! You punch in the parameters, save it to the DEQX and there you go, you can immediately listen to your design! And you can do silly things such as 96db/octave filters that you can't even think of in the analog world; no more physical limitations, just numbers crunching !

One element I can add to this thread is how surprised I was to observe how crucial is the crossover frequencies selection and how it can change the voicing of the system. While the frequency measurement of two drivers may show that they can easily handle a given frequency range, the resulting "voice" may be quite different. So I played a lot with the P1-4 buttons (Drewan77 explained) to find out the best calibration so my ScanSpeak Revelator performs at their best. By the way, Drewan77, I got the same result: 100 Hz is my best option to integrate smoothly my big guys (15" subwoofers).

In closing, from a DIY speaker builder point of view, I'm a little sad because my speakers are now performing so well, I can't imagine what I could do to improve them, which means I have to retire from this hobby..!! Fortunately, I'm also a passionate music lover and I now have a full discography to re-discover !

Regards,
Denis

Has anyone tried putting a High Fidelity Cable Ultimate Reference Rhodium power cord on their DEQX? I'm just curious as to the effect that putting a game changing power cord on a game changing piece of electronic gear may sound like.
Could be that two 180's = 360 and put you right back where you started???

Cheers,
John

Hi Guys, I have read several post, but not near all, this may have been addressed. I have no doubt that the DEQX could be a game changer, but it would require Biamping, triamping etc.
The biggest problem in any speaker is the crossover. Coils suck the life out of music. If you are willing to remove your speakers crossovers, run an amp channel on each driver, properly set up the electronic crossover, then adjust time delay and eq to your room, there is no doubt that any of us will have performance that we have only dreamed about.... assuming that the DEQX is clean and does not mess up the sound of the other electronics in the system. Unfortunately for me, this is a product out of my reach... I have found a substitute that I will be trying shortly, it is called Mini-DSP... I have purchased it. It comes in 2 to I believe up to 10 Channels... I have gutted my speakers crossovers, but have decided to do some cabinet work so it will be some time before I get it all up and running... I can't imagine the Mini DSP doing anywhere near the job of the DEQX, but it does have full electronic crossovers, full eq capabilities and full room correction software with a calibrated mic available. I'm excited to give it a try and very curious to see if anyone else has tried this inexpensive product?
Thanks, Tim

Thanks for your further comments, gentlemen.

Psag, even if I do end up removing the Classe CP-60 from the system, I don't envision selling it in the foreseeable future. It's much too good a performer, IMO, to be selling it for what I suspect it would bring. (I paid $1350 for it about 6 years ago, when I believe it was something like 8 years old). So I'd keep it as a backup, or possibly use it in a second system.

But regarding keeping it in the system along with the DEQX, my instinct is generally to have as little in the signal path as necessary. Also, as you can tell from the photos in my system description, my setup can't readily accommodate both units physically. But we'll see, of course, how the sonics work out with the DEQX installed in the configuration I described.

Best regards,
-- Al

Al, for the configuration you plan on using you won't need to worry about any manual time alignment as the 3 sets of outputs won't be feeding multiple power amps or subs (which is what they are really designed for). The only graphs you will need to interpret manually will be the in-room measurements at the listening position and that's very easy

That makes your setup much simpler as the HDP-4 will automate correction to speaker drivers driven by one power amp. It will hear your speakers as a single set of frequencies with any passive crossovers included in the signal path and adjust accordingly. You won't use the active crossover facility, just speaker correction to one stereo pair and the potential for room equalisation as you see fit

At a later date you have the opportunity to try all the other features, adding more power amps, speakers without passive crossovers, maybe subs etc. As long as you always measure with the power amps and cables linked to the drivers they will be running, you can even use different brands and wattages of amps for bass-mid-treble and DEQX calibrates and adjusts accordingly. Better to stick to one brand/rating though but it does allow you to adapt the system without needing to purchase 3 new sets of power amps in one hit

Regards Andrew

Al,

I will stay tuned. I'm very interested in your finding as I'm sure are many here.

Not to make more work for you, but I would be very interested to understand the effects of DEQX on various speakers of various designs, in a sense as a potential objective way to measure speaker distortion, perhaps on some relative scale.

Don't rush to dump your preamp. The DEQX is essentially transparent, so you can use them together if you like what the preamp adds to the sound of your system.

Thanks for the nice words, guys, and especially to Andrew for the kindly offer.

I'll most likely be ordering the HDP-4, together with the DEQX/Earthworks M23 calibration kit, in January or February. As a technically oriented person, I'll try to implement all of the procedures myself, at my own (slow and deliberate) pace. I suspect that will extend over at least several weeks before I either declare the profiles and settings to have been finalized, or decide that I need to take Andrew up on his kindly offer and/or utilize the DEQExpert service.

I'm planning on using the HDP-4 in place of, rather than in series with, my existing preamp (a Classe CP-60), which receives inputs from five different sources, and provides outputs to three different destinations.

My two most critical sources are CDP and phono. Pending possible revision during my listening tests, I'm planning on connecting a digital output of my Bryston CDP to the HDP-4 via AES/EBU. I'll connect the output of my phono stage (actually, the phono section of a vintage Mark Levinson ML-1 preamp, accessed via tape outs) to the HDP-4's unbalanced analog input.

For the less critical sources, I'll connect a digital output of my Squeezebox Touch (which I only use for internet radio) via Toslink. I'll connect the outputs of my vintage tuner and Tandberg cassette deck (I still have occasion now and then to play some musically and sonically excellent classical cassettes from way back when on the Connoisseur In Sync Label) to a mechanical switchbox that will select between them, with the output of the switchbox connected to the HDP-4's balanced analog input via RCA-to-XLR adapters.

I'll be connecting one of the HDP-4's three sets of outputs to my VAC power amp, one to my STAX headphone amp, and one to the cassette deck (although I can't recall the last time I ever recorded anything with it). Obviously the outputs to the Stax and the Tandberg will be configured for bypass mode.

Thanks again. Best regards,
-- Al

Woo-hoo, Almarg!! :-)
I was happy to read your post indeed & am looking forward to your personal experience with time-coherency thru DEQX.
From my personal experience & from Bruce's experience I believe that you will be nothing short of amazed what time-coherency can do for music play-back. It's the only way to go & I'm sure that, like myself & Bruce, once you get used to time-coherent speakers you won't ever go back. :-)
Like many others I'll be watching this space for your feedback.
Thanks for joining the time-coherent "gang" - you will not be disappointed....

Alright, will love to read about what you have to say regarding your DEQX purchase Al. Best of luck on that. I'll be watching.

Al, great to hear. I am confident that you will be equally impressed when you get the HDP4. If you need assistance with any part of the configuration or interpreting the graphs, I am more than happy to help

There are some really useful features that even the enormous manual doesn't make clear. I am also much cheaper than the DEQXpert service (ie free !)

Regards
Andrew