[denverdoc]

[Btw, just to clarify, the Hypex amp modules aren't technically considered digital.  They use a conventional analog input stage and PWM output stage.[/quote]

Mac, point taken and a source of confusion for many--closer I suppose to digital in that transistors are either on or off if I understand correctly.
Cheers,
John

[John Ashman]

Doug,
    If you like the idea of your favorite preamp/DAC, what you might consider is NHT's Xd.  It is a PDC and is designed for use with a preamp and external sources, so you're not getting any digital volume control or digital ins, IOW, exactly what you need, BUT you're also getting a very pretty set of speakers that couldn't possibly be more tweaked to get the most out of DEQX.  

If I have a quibble about Xd it's that it does NOT have a digital input, source switching or volume control, let alone a remote - it's designed for use with an external preamp.  I'd gladly pay an extra $500-$1000 for those extra features, but that isn't on the front burner and could show up later as an option or as part of the system (basically a PDC-P based system).  I don't think the extra AD/DAC stage is very damaging to the sound, perhaps even inaudible, certainly less than the damage done by most preamplifiers or other analog component.

HOWEVER, this setup is ideal for you, since you prefer to not use digital inputs or VC.  So, you're getting a PDC, but you're getting amps, stands, subwoofer, cabling and, believe me, I don't think the speaker part of the system could possibly be more ideal for DEQX.  As I said, they've been refining this design for over 4 years, it definitely was not rushed to market (though I'd now appreciated it if they started building tad faster at this point!).

BTW, my argument is a subtle one - AD/DA conversion these days is VERY transparent, in fact, done well, it IS transparent.  But I err on the side of avoiding it when you can, why not?  You can't make the sound better through additional AD/DA steps, but you lose very little to nothing subjectively when you do.  So, adding a DAC won't make your sound better, but it may not make it worse.  I just wouldn't go out and buy DACs and a preamp to *improve* the sound of the PDC or PDC-P.

[mac]

might consider is NHT's Xd...  BUT you're also getting a very pretty set of speakers that couldn't possibly be more tweaked to get the most out of DEQX...

And it's a good thing that it's so highly tweaked because unlike the actual DEQX PDC-2.6 it lacks adjustability (crossover type, crossover point, crossover slopes, inability to run driver correction, delay, EQ, room correction features, etc...).

[John Ashman]

And it's a good thing that it's so highly tweaked because unlike the actual DEQX PDC-2.6 it lacks adjustability (crossover type, crossover point, crossover slopes, inability to run driver correction, delay, EQ, room correction features, etc...).

Sorry, Mac, that's untrue.  It's not user adjustable YET, but there are room boundary and room EQ functions built in and the user software is in development.  There is also likely to be a "high output" crossover option when used with dual subwoofers.  If you tried to run driver correction, adjust delay, etc, you'd just take a highly tweaked system and make it worse.  Remember, this system is being done in full cooperation with DEQX themselves, it's not just a PDC added to an existing system.  To borrow your own analogy do you think you could tweak a McLaren F1?  In your garage with your existing tools?  You'd more than likely just break it.  

So, the point is that this has been already tweaked far better than any person could possibly do themselves.  The thing about DEQX is that it opens up huge new powerful tools for the DIY enthusiast.  But if all you care about is the final result, IMO, Xd is way ahead of everything right now in sonic performance.  And I have a little more perspective because I'm a dealer for both.

[mac]

Sorry, Mac, that's untrue.  It's not user adjustable YET, but there are room boundary and room EQ functions built in and the user software is in development...

So, it *is* true as of right now.  The room EQ as I understand it is simply a room boundary setting.  I'm sure you'll correct me if I'm wrong but the XD system has no computer user interface to alter its settings and no measurement capabilities.

So, the point is that this has been already tweaked far better than any person could possibly do themselves.

As far as driver correction goes I have no reason to believe that NHT would do any worse a job configuring their feature deprived PDC than a full-fledged PDC user could achieve himself.

The thing about DEQX is that it opens up huge new powerful tools for the DIY enthusiast. But if all you care about is the final result, IMO, Xd is way ahead of everything right now in sonic performance...

Yes it does.  Personally, I do care about the end result very much.  Maybe that's why my speakers resemble the Xd?  Even the Xd is built to a price point and has compromise (crippled PDC functionality, questionable quality metal dome tweeter, single sealed box subwoofer, etc).  A full-fledged PDC gives me the capability to upgrade drivers on a whim.  I’m sure there are others here that would agree that having that capability is priceless.

[John Ashman]

So, it *is* true as of right now. The room EQ as I understand it is simply a room boundary setting. I'm sure you'll correct me if I'm wrong but the XD system has no computer user interface to alter its settings and no measurement capabilities.

Incorrect.  the room boundary is a simple user preset that compensates for each satellites proximity to walls.  Room correction is built in, is *possibly* accessable via DEQX software, though I did NOT try it with *their* prototype!  A mistake could have had some unhappy NHT folk.  The Xd DOES have a computer user interface and simply needs to have modified, easy to use software made that won't allow someone to screw up the professionally set up sound of the speakers.  The software will be purposefully "lite", the power of the XdA is anything but a stripped version of the PDC.  And, as I said, would you buy a car from Carroll Shelby and then try to undo his engine work?  I think not.

As far as driver correction goes I have no reason to believe that NHT would do any worse a job configuring their feature deprived PDC than a full-fledged PDC user could achieve himself.

That's a back-handed compliment, but yes, they have an advantage because they have a far better place in which to measure them.  AND, they can and have done extensive listening tests to make sure that the processing applied actually results in improved performance, not just altered performance.  I have measured speakers and have managed to make them sound worse (usually dipoles or line arrays though)

Yes it does. Personally, I do care about the end result very much. Maybe that's why my speakers resemble the Xd?

I haven't seen your speakers, the link comes up as gibberish.  I'd be glad to comment though, if you'd like

Even the Xd is built to a price point and has compromise (crippled PDC functionality

You call it "crippled", I call it "fool proof" with the emphasis on "fool" if you were to try to remeasure them.

questionable quality metal dome tweeter

Call SEAS and tell them their top-end aluminum tweeter is "quesionable". This tweeter measures beautifully, is extremely low in distortion.  The current "in vogue" tweeters often are utterly rolled off and/or have poor dispersion and generally don't measure well at all.  THAT is what I would call "questionable"

single sealed box subwoofer

If dual 10" sealed subwoofers (for improved transient response, time/phase accuracy and natural FR accuracy) and bipolar force cancellation (low cabinet vibration, improved transients) isn't enough for you with 105dB output, you can buy a second for stereo bass and 111dB output.  If that is compromised, well, build your own subwoofer tower, I suppose a la Genesis.  Speaking of which, I had Genesis 501s with six 8" servo-control woofers going and a single dual-10" Xd woofer sounded dramatically better than the six servo woofers in the Genesis.  I've never had the pleasure of hearing dual Xd woofers.  

A full-fledged PDC gives me the capability to upgrade drivers on a whim. I’m sure there are others here that would agree that having that capability is priceless.

If you're a DIY guy.  If all you want is exceptional sound, better than DIY, for no hassle and a remarkably low price, then you can just get Xd.  The "full-fledged" PDC in the Xd allows THEM to upgrade the speaker in the future when it makes sense instead of "on a whim".  DIY guys have "whims", music lovers like to listen to music and are bored playing with gear.  DEQX is for DIY guys, Xd is for music lovers.  That's why I sell both.  Both are equally valid for their intended audience.  You just have to decide which camp you fall into.  Just don't get so cocky that you think you can outdo the professionals.  You really can't.  At best, you'll achieve "different".  Nothing wrong with that if you're doing it for the fun of it.

[mac]

John, can't one be both a DIY guy and a music lover?  Sounds like you're trying to make the case that they are mutually exclusive.  

I haven't seen your speakers, the link comes up as gibberish. I'd be glad to comment though, if you'd like.

Sure John, knock yourself out.  Just click on the photo below:

.

Call SEAS and tell them their top-end aluminum tweeter is "quesionable".

Actually, SEAS's top-of-the-line tweeter isn't an aluminum dome.  Metal domes are prone to ringing within their operating range and that's why SEAS' best domes have been soft fabric.  They did just introduce some new Excel line tweeters at the '05 CES and one does happen to be aluminum (T29AF001).  Its response curve doesn't look great but time will tell...

DIY guys have "whims", music lovers like to listen to music and are bored playing with gear. DEQX is for DIY guys, Xd is for music lovers.

There you go again.  

Just don't get so cocky that you think you can outdo the professionals. You really can't.

If you say so, John.  

[John Ashman]

Hey, not bad!  Now if you can just get the baffle size down, get the diffraction on that baffle down, get that front panel more rigid (I noticed you didn't use a Corian type composite for that ), well, at least you're way up on most of the folks using DEQX, but anyhoo, this is Xd for those who haven't seen it:

[mac]

Hey, not bad!  Now if you can just get the baffle size down, get the diffraction on that baffle down, get that front panel more rigid (I noticed you didn't use a Corian type composite for that )..

It's a very common misconception that small baffle size reduces diffraction effects.  What does, is large radius corners on baffles that are not infinite in size.  Anyway, diffraction effects can to a large extent be completely corrected by the PDC since their effects are linear in nature.  OTOH, aluminum dome tweeter ringing can't.  

No, I didn't use Corian.  3" thick MDF was easier for me to work with.  I'd be happy to put my cabinets up against the NHT for deadness and low diffraction.   I thought you might comment on my use of dipole woofers.  Oh, well.  

[John Ashman]

Actually, SEAS's top-of-the-line tweeter isn't an aluminum dome. Metal domes are prone to ringing within their operating range and that's why SEAS' best domes have been soft fabric. They did just introduce some new Excel line tweeters at the '05 CES and one does happen to be aluminum (T29AF001).  

Actually, its the the other way around.  Fabric would ring more in the bandwidth but would be fairly well self-damped, aluminum is more pistonic, but rings like a bell, typicall around 22kHz where it shouldn't be perceptable.  Some poorer aluminum tweeters range down in the audible range causing fatigue.  I've alwas found fabric tweeters to be "pleasant", but not realistic on cymbals (I'm a drummer).  I'd rather have realism than this current audiophile trend towards rolled off, "pleasant" tweeters.  I do like ribbons, though the ribbon you're using is likely notably beamier than the tweeter NHT is using, which is critical to achieve the coherency and wide sweetspot they were after.  

BTW, I don't think being a DIY guy and a music lover is totally mutually exclusive, but wouln't spending hours and hours building cabinets, downloading plans and otherwise dinking around take away from your music listening

[mac]

BTW, I don't think being a DIY guy and a music lover is totally mutually exclusive, but wouln't spending hours and hours building cabinets, downloading plans and otherwise dinking around take away from your music listening.

Do you have any hobbies, John?  Chances are you do and it probably also takes you away from music listening.  Does that mean you aren't a music lover?  No.  At least I listen to music while I'm building speakers and amplifiers.     Cheers, mac.

[John Ashman]

My hobby is arguing with you while listening to music off of my laptop

[doug s.]

Doug,
If you like the idea of your favorite preamp/DAC, what you might consider is NHT's Xd. It is a PDC and is designed for use with a preamp and external sources, so you're not getting any digital volume control or digital ins, IOW, exactly what you need, BUT you're also getting a very pretty set of speakers that couldn't possibly be more tweaked to get the most out of DEQX.

If I have a quibble about Xd it's that it does NOT have a digital input, source switching or volume control, let alone a remote - it's designed for use with an external preamp. I'd gladly pay an extra $500-$1000 for those extra features, but that isn't on the front burner and could show up later as an option or as part of the system (basically a PDC-P based system). I don't think the extra AD/DAC stage is very damaging to the sound, perhaps even inaudible, certainly less than the damage done by most preamplifiers or other analog component.

HOWEVER, this setup is ideal for you, since you prefer to not use digital inputs or VC. So, you're getting a PDC, but you're getting amps, stands, subwoofer, cabling and, believe me, I don't think the speaker part of the system could possibly be more ideal for DEQX. As I said, they've been refining this design for over 4 years, it definitely was not rushed to market (though I'd now appreciated it if they started building tad faster at this point!).

BTW, my argument is a subtle one - AD/DA conversion these days is VERY transparent, in fact, done well, it IS transparent. But I err on the side of avoiding it when you can, why not? You can't make the sound better through additional AD/DA steps, but you lose very little to nothing subjectively when you do. So, adding a DAC won't make your sound better, but it may not make it worse. I just wouldn't go out and buy DACs and a preamp to *improve* the sound of the PDC or PDC-P.

hi john,

ya, i am aware of the nht, but i really wanna do my own line source...   i'm figuring yure right about the transparency of the ad/da, & figure it will be about as good as i can get for loudspeaker x-over, and i am excited about the speaker/room correction capability.  i will yust have to live w/the "backwards technology" of my present preamp & sources...  

regards,

doug s.

[doug s.]

Actually, its the the other way around. Fabric would ring more in the bandwidth but would be fairly well self-damped, aluminum is more pistonic, but rings like a bell, typicall around 22kHz where it shouldn't be perceptable. Some poorer aluminum tweeters range down in the audible range causing fatigue. I've alwas found fabric tweeters to be "pleasant", but not realistic on cymbals (I'm a drummer). I'd rather have realism than this current audiophile trend towards rolled off, "pleasant" tweeters. I do like ribbons, though the ribbon you're using is likely notably beamier than the tweeter NHT is using, which is critical to achieve the coherency and wide sweetspot they were after.

hey john,

have ya ever heard the latest proac fabric tweets/  absolutely phenomenal - perhaps as good as it gets.  (for non-ribbons, that is!     ).  they are amazingly airy & extended; proac rates 'em to 30khz...

regards,

doug s.

[jhenderson010759]

Well, I received my PDC 2.6P Friday and spent Saturday morning taking measurements and using the system.  Unfortunately, I am officially discouraged with the results.  

On a positive note, I was able to correct and verify the performance of my North Creek Rhythms and Poseidon subs to near textbook performance in the near field.  But to be fair, I was able to do nearly as well measuring via MLS in SoundEasy 9.0 and adjusting my previous electronics (Roland M1000 feeding Behringer DEQ2496 into DCX2496) .  True, I couldn't implement a perfect inverse transfer function like the PDC can, but I could tweak the drivers in these speakers to within +/- 1 dB or so.  

My disappointment stems from the fact that my listening room is so damned recalcitrant.  The room is large, has wood floors and flows openly into the dining room and foyer - all of which also have hardwood or tile flooring.  So, it's just too reverbrant.  I have constructed and mounted numerous traps, using Owens Corning SelectBoard throughout the room, but it just isn't enough.  

When using Room Measurement in the PDC, I still see huge peaks and troughs in the measured response.  One trough is actually -30 dB at 170 Hz or so.  What can you do with that?   I doubt that even Mondo traps could reign that beast in!  And, it's not just the low frequencies - the audio band from 500 Hz to 20KHz is also riddled with undulations spanning 10 dB or more plus a substantial roll-off in the >10Khz region.  

Anyway, I am about ready to raise the white flag and go back to listening to headphones.  So frustrating, since I feel that in the right environment, this system could be satisfying.  

Building the system is fun, but I was hoping it would generate music sometime within my lifespan.  

By contrast, I have a pair of small Taylor Minuette bookshelves and a sub in my den driven by a Yamaha  receiver and it sounds wonderful.  Guess I just spent too much time and effort on the main stereo.  

I have noticed that some users, such as Mac, advocate dipoles.  Is there any sort of consensus view that a dipole will help throughout the audio band, or are they principally helpful only in the bass region?

[mac]

Jim - If you bought your PDC from a dealer I'd suggest you consult with them.  OTOH, if you'd like to PM me I can share my thoughts with you.  Cheers, mac.

[John Casler]

Hi Jim,

Welcome to AudioCircle.  Sorry to hear of your difficulties.  Was Andre able to help at all?

Where are you in So CA?  Are you a member of the LA & Orange Co Audiophile Society?

In any event, hope you can get it "dialed in".  

I may want to "pick your brain" a bit since I (if I ever get my laptop back) will be trying out the DEQX on my system.

[John Ashman]

Jim,
     First, no, there's NOTHING you can do about huge dips with the DEQX.  Peaks, yes.  Dips, no, not 30dB ones - that's an acoustics problem.  However, you can move the sub.  THAT will help.  A second sub would help.  Is the sound bad in the  mids/treble or the bass?  Secondly, I do tend to like big powerful speakers and, actually, dipoles in a big room as they help deal with the floor/ceiling and sidewall reflections.  Or big ribbon arrays might work better and may be a better expenditure over the DEQX.  The DEQX is great at fixing speakers, it's not a fix for bad rooms, except for dealing with room mode peaks.  Fortunately, dips are not as noticeable as peaks.  Have you tried rugs?  That would sure help.  The more the better.

[ted_b]

Jim,
Welcome  aboard.  Make sure you do two things as a DEQX owner:
1)  send an email to Kim Ryrie and Ian at DEQX and introduce yourself.  Although they are  founders and very busy right now, they are also very helpful.
2)  Get yourself signed up for the Yahoo group DEQXBeta.  It is there that a lot of technical help can be found.  

Don't get discouraged.  The learning curve can be steep, but it means you'll know a lot more this time next week.

Make sure you are smoothing the room results, and make sure you take numerous measurements within a foot radius of your sweetspot.  You may find better results within 6 inches or so.  Also, make sure you zoom in on 250hz and below and worry about that intitially.  The 30db trough is rough, but you might find better positions where 10-15 db can be erased by the DEQX autoeq, with a little tweaking.

Ted

[denverdoc]

Well, I received my PDC 2.6P Friday and spent Saturday morning taking measurements and using the system.  Unfortunately, I am officially discouraged with the results.  
 ...

Jim,

Actually, to put a bit of spin on things, at least now you have a definitive notion of where the problems are and address those, and by using the deqx each step of the way know what your gains are

 I guess I am lucky in that I have not even felt compelled to really use the room eq 'cept to flatten the bass a bit in the listening position. Hardwood floors are death, and I am always amazed to see these high end speaker ads in upscale rooms with sparse furnishing, and hw floors. Right.

 I will disagree on one point, while your FR may have been almost as good with the Behringer gear, no way the phase response and group delay came close to being as well behaved. As I mentioned a page or two back, having all your ducks in a row, adds noticeably to jump factor IMHO. And the benefit in imaging may not yet be apparent given all the reflections you're having to contend with.

Customer support is huge with this product and if you haven't already joined us on the users forum, do so ASAP and you will get any number of helpful suggestions.

John