[John Ashman]

Uh huh.  

Seriously though, DEQX automatically corrects for things such as making sure the drivers sum properly and does it effortlessly.  It removes or avoids issues that usually require compensation networks or notch filters and you can run lower crossover points which means far better dispersion.  Using capacitors, resistors or inductors to do this is like using an abacus instead of a computer.  I'm all ears wanting to know what DEQX can't do in this regard.

[ludavico]

Bingenito,  I read his comments in TAS the magazine itself.  I doubt if it is on-line.  There is only a paragraph dealing with DEQX, but it is pretty unequivocal.  

John

[John Ashman]

Don't blame DEQX for a poor implementation of it!!!!!!!!   I hope TAS didn't.  The more I learn about the Overkill Audio system, the more I believe it would handily get it's ass whipped by the NHT Xd system and even most decently done DIY/DEQX systems such as the HT3/Cornelian/Thiel or other well designed systems.

[Rick Craig]

Uh huh.  

Seriously though, DEQX automatically corrects for things such as making sure the drivers sum properly and does it effortlessly.  It removes or avoids issues that usually require compensation networks or notch filters and you can run lower crossover points which means far better dispersion.  Using capacitors, resistors or inductors to do this is like using an abacus instead of a computer.  I'm all ears wanting to know what DEQX can't do in this regard.

I'm not saying that the DEQX cannot emulate or exceed the best passive solutions. The key is being able to know how to take the right measurements, accurately apply the  driver correction, and select the right crossover points / slopes. Having spent some time with two DEQX owners I can verify that these areas can create problems for having an optimal design.

[John Ashman]

That's why you can't just expect to whip out a DEQX-based system any more than a passive system.  It's faster, perhaps, but then, again, DEQX leaves you with just the sound of the drivers/cabinet, so the next thing you know, you're doing a total overhaul on those too.

My main point is that I can't think of an instance where inserting passive components into the signal path would help DEQX do it's job better or make the final result better.  

I've worked with a lot of customers on DEQX and handled probably 4 or 5 returns too because it is more complex and more difficult to implement than they'd thought.  It's definitely a difficult system, though they're working to make it easier.  And a lot of people try to apply it to inappropriate designs and then wonder why it isn't a world of difference or try to use the power of it inappropriately and then blame the machine.

[Rick Craig]

That's why you can't just expect to whip out a DEQX-based system any more than a passive system.  It's faster, perhaps, but then, again, DEQX leaves you with just the sound of the drivers/cabinet, so the next thing you know, you're doing a total overhaul on those too.

My main point is that I can't think of an instance where inserting passive components into the signal path would help DEQX do it's job better or make the final result better.  

I've worked with a lot of customers on DEQX and handled prob ...

Actually I wasn't talking about adding passive components on top of using the DEQX. I do think for most audiophiles an integrated solution like the NHT design is the best way to go. For advanced DIY speaker builders and manufacturers / designers the PDC is an excellent design tool.

[John Ashman]

Ah, I misunderstood

[DSK]

....  It removes or avoids issues that usually require compensation networks or notch filters and you can run lower crossover points which means far better dispersion....

John,
I recall (a few hundred pages back in this thread   ) you identified criteria for an optimal DEQX-compatible speaker and it was a 3-way.

Given your statement above, is it fair to assume that with DEQX, the usual benefits of a 3-way speaker over a 2-way speaker become less? If so, is it therefore fair to say that it may be better to use DEQX for a '2-way + 2 subs' setup rather than a straight 3-way setup without subs? This would seem to give better low end extension (and dynamic range and effortlessness) and require less amps (assuming plate amps already in active subs) and speaker cables while not having the usual compression/distortion/dispersion issues of a 2-way speaker?

[John Ashman]

2-way + 2 subs = 3-way

Either way, works fine.  The ideal driver complement (generally) would be:

1" + 4" + 8"
1" + 5" + 10"
1" + 6" + 12"

The 1st doesn't have a ton of advangages, the 3rd one gives you the best bass extension and output, but the 2nd gives you the best combination clarity, dispersion, integration, which is why NHT chose it after a *lot* of monkeying around with it.  I hate to always bring up Xd as the paradigm, but they've had over 4 years of refinement on this system, so the design is as sound as it could possibly be.  Copying NHT's system is like finding a big shortcut because they did all the basic groundwork.

[DSK]

2-way + 2 subs = 3-way

Yes, I do realise that. What I was trying to get at was that DEQX enables us to invoke a HP filter on the bottom of the midwoofer in a 2-way design, and the steepness of the slopes available (eg. 100db/octave) means we can run the midwoofer a bit lower than we could with a passive HP filter and thus reap the rewards of crossing over to the sub at a lower frequency. A good active 12" sub would typically extend down further and flatter than a 12" driver in the main speaker box (plus be in a separate dedicated box that can be moved independantly of the main speakers and have adjustable phase, gain, LF rumble filters etc) thus providing a more effortless, extended and perhaps dynamic setup than a 3-way with a 12" woofer but no sub. What I am wondering is whether you feel these benefits (on say a 1", 6", + 12" sub setup) equal or outweigh the benefits of a DEQX'd 3-way speaker with a dedicated midrange driver but no subwoofer (eg. 1", 6", 12", no sub)?

Either way, works fine.  The ideal driver complement (generally) would be:

1" + 4" + 8"
1" + 5" + 10"
1" + 6" + 12"

The 1st doesn't have a ton of advangages, the 3rd one gives you the best bass extension and output, but the 2nd gives you the best combination clarity, dispersion, integration, which is why NHT chose it after a *lot* of monkeying around with it...

Are these factors somewhat dependent on the particular drivers or tied only to their size?

[John Ashman]

Yes, I do realise that.

I knew you knew that, just saying that, for the DEQX, there is no difference.  

What I was trying to get at was that DEQX enables us to invoke a HP filter on the bottom of the midwoofer in a 2-way design, and the steepness of the slopes available (eg. 100db/octave) means we can run the midwoofer a bit lower than we could with a passive HP filter and thus reap the rewards of crossing over to the sub at a lower frequency.

Yes, and this makes for a *massive* upgrade in integration, bass clarity and "snap".  The little NHT Xd sub sounds better than the Evolution subs even though the Evos have better, bigger, more badass woofers, so I can only attribute this to the DEQX processor and the excellent crossover

A good active 12" sub would typically extend down further and flatter than a 12" driver in the main speaker box (plus be in a separate dedicated box that can be moved independantly of the main speakers and have adjustable phase, gain, LF rumble filters etc) thus providing a more effortless, extended and perhaps dynamic setup than a 3-way with a 12" woofer but no sub.

That would *entirely* have to do with the quality of the bass drivers.  There are towers that will kick the tar out of most subs.  For instance, I would expect the Salk HT3 to knock around a lot of subs.  

What I am wondering is whether you feel these benefits (on say a 1", 6", + 12" sub setup) equal or outweigh the benefits of a DEQX'd 3-way speaker with a dedicated midrange driver but no subwoofer (eg. 1", 6", 12", no sub)?

Well, as you mentioned, with a sub/sat, you can move the sub to where it sounds best and it gives you a smaller baffle for the sats.  There's not a ton of advantage to a tower with DEQX except for saving space.  That's why Xd is a sub/sat.  Better imaging, more flexibility, better bass placement.  

Are these factors somewhat dependent on the particular drivers or tied only to their size?

Somewhat on the drivers, but size does have a direct effect on whether the speaker is going to beam at a particular frequency.

[Marbles]

John, the more you shout how great the DEQX is, the less I'm inclined to try it.

OTOH, when a Jim Griffen whispers that he likes it, that carries a tremendous amount of weight with me and makes me want to try it.....

Just thought you should know how I feel, as I'm sure there are others that feel the same way I do.

[John Ashman]

John, the more you shout how great the DEQX is, the less I'm inclined to try it.

Dude, it's a DEQX PDC thread.  I'm not trying to convince *anyone* to try it.  Have I ever said "hey, you should do this!"?  Nope.  I'm just talking about what it can do, can't do, what works best with it, what doesn't, etc, etc.  If you don't want to try it because, in a PDC threat I talk too much about "how great the DEQX is", well, I suppose we could just end the thread and not talk about it at all. Or we could have the "enthusiastic PDC thread" and the "quiet, understated PDC thread" If you want to try it because of something Jim says, that's fine, whatever works for you.  I can't tailor my comments to each individual's sensibilites.  I don't have time for that.  Obviously, the DEQX isn't a magic pill and good speaker design is critical.  If I were as bad as you imply, I'd say "yeah, take those Pioneer 2-ways and DEQX them!"  Sorry, it's not that capable.  Sorry if my enthusiasm is abrasive to you, but what can I do?  Fake it for you?

[ekovalsky]

Yikes...anyone catch Robert Greene's comments in the latest TAS on the DEQX'd Overkill system at CES?  

Damn, that is the first time I ever heard him say he had to leave a room (well, running actually) clutching his ears.  

This is the same guy that publicly drooled over the Dali Megalines (which is also somewhat uncharacteristic).

John

Ludavico,

What exactly did he say, and where in the magazine did you seen it?  I glanced through the latest issue (one with the ugly Gilmore's on the cover) and only saw him mention it in the show report.  His comments about the DEQX/OVerkill were actually quite favorable other than "some problem" with the upper bass.   I did notice the Overkill system listen at least twice in the "Best of" sections, and a few buddies who heard them at CES thought they were exceptional.

As for the Megalines, I auditioned them an left very unimpressed -- they had very anemic response in the bottom three octaves which was unacceptable for a speaker marketed as full range.  Its upgraded twin, the TacT LS1 which unfortunately will never see mass production, has more a more sensitive ribbon and better woofers and is NOT marketed as full range, rather it is designed to work with the TacT subwoofers.

One Megaline owner in TX had been unimpressed with his pair, which replaced the venerable Sound Lab A1.  But, recently he told me that after 400 hours the bass started coming alive so maybe they just need a lot of break in.  The pair I heard undoubtedly had very low hours...

[John Ashman]

Here's a speaker that is ideal for DEQX if anyone has $3K!

http://cls.audiogon.com/cgi-bin/cls.pl?spkrfull&1115308396

Also, FWIW, got my Xds in on Friday.  Awesome.

[doug s.]

Here's a speaker that is ideal for DEQX if anyone has $3K!

http://cls.audiogon.com/cgi-bin/cls.pl?spkrfull&1115308396

Also, FWIW, got my Xds in on Friday.  Awesome.

those suckers look awesome as-is.

doug s.

[ekovalsky]

Here's a speaker that is ideal for DEQX if anyone has $3K!

http://cls.audiogon.com/cgi-bin/cls.pl?spkrfull&1115308396

Also, FWIW, got my Xds in on Friday.  Awesome.

those suckers look awesome as-is.

doug s.

I had actually emailed about these, since they were local... here is the response I got  

Hi. these were part of a police action and are in a
warehouse. (thats why their cheap) you can check out
celestial at 2730 thomas in phoenix. in their back
room is a pair of altairs which are similar but
smaller..if you like those you'll love these..i would
not mention these as they will are not getting any
proceeds from their sale. give me a call if you
like...
480-748-5883...mike

[ekovalsky]

Just realized those Audiom W 13" woofers go for about $1k each, so the price on these is really good.  Maybe too good    Don't want to burn myself if I touch them.

Later in the week I'm going to drive down to their manufacturer http://www.celestialav.com to audition a similar pair.  If I like them I just may buy this pair.  At the least they would make nice rear channels  

I've asked more specifics about the "police action".  Obviously I need to make sure they aren't stolen

 

[doug s.]

Just realized those Audiom W 13" woofers go for about $1k each, so the price on these is really good.  Maybe too good    Don't want to burn myself if I touch them.

Later in the week I'm going to drive down to their manufacturer http://www.celestialav.com to audition a similar pair.  If I like them I just may buy this pair.  At the least they would make nice rear channels  

I've asked more specifics about the "police action".  Obviously I need to make sure they aren't stolen

 

if they're being adwertized on the 'net like they are, on a prominent site, w/reference to police action, they're likely not stolen, but seized property, due to drugs, unpaid taxes, etc.  

yup, those focal drivers are fantastic - i wish i had a place for those...

doug s.

[JoshK]

yup, those focal drivers are fantastic

'cept for their tweeters which are bloody awful!