[JoshK]

Jim/Phillip/Rick,

Agree with you on the electronics/speaker balance for the most part.  It is easier, more wife accepted, and cheaper for the most part to swap a component than speakers.  I think this is why the marketeers have focused so much attention on the component du jour.

I just ordered a DEQX for my own hobby'ing.  I got some work left to do on finishing up my 6 channels of UcDs, but I have 3-4 weeks to wait before my DEQX is ready.  I'd love to get a jump start on learning by getting into the DEQX private site.  I am going to have to contact my dealer about getting a password/account.  

I think Phillip and Rick have the potential to really get a jump start on the competition in terms of where I think the market is going to eventually lead.  I think your approaches are exciting.

My own DIY'ing and modifying my current speakers is mirroring that of Phillips with external passive (using speakons) and eventually bypassing it when the DEQX/UcDs are up and running.  

Phillip -  Out of curiousity, have you experimented whether the length of cables between your outboard xo and the speakers in relation to the length between the xo and the amps makes any difference?  I can't imagine it would make much of a difference but then again stranger things have happened.    I am thinking about making a box for my external xo's that fits on my rack so the wife won't dissaprove of extra boxes sitting on the floor.

[John Ashman]

I just noticed that there is an excerpt on the DEQX site from a NHT/Xd review that David Rich did for the Sensible Sound. David is a very reliable source IMO having been the technical editor for The Audio Critic. This is great news to hear. Can anyone fill me in on the rest of the review?

I don't know if this is redundant, and it might even be the clip I sent to DEQX that you read, but I had to type this in and the article is a long assed one that basically talks about the power of DEQX and then NHT's application of it, followed by the following salient bits:

The cabinet is molded from dense composite material that is similar to the solid surface material in your high-end kitchen. The satellites are acoustic suspension. This is the optimum design choice when matching a small woofer to a subwoofer.

NHT showed the final production unit in a large NYC hotel with no attempt to do any acoustical improvement to the room. They even had a big mirror hanging on the wall where the speakers were placed. For the three days, NHT demoed the speakers to press and pro audio folks. I got more than half an hour to listen to the speaker in private with my own source material. With my CD-R compilations I was able to check out 15 of my most revealing test tracks and I will tell you I was very impressed. The bad news is that the small satellite system size does limit dynamic range. I was told that the use of two crossovers, which would allow for a higher crossover between the satellites and subwoofer, would improve the situation signficantly but NHT is not shipping the system in this form. [this would be easily upgradeable in the home. We also recommend dual subs for larger rooms which substantially helps the situation].

But the good news is really good news. In my opinion the only thing as tonally neutral as these speakers is the sound heard from the world's best headphones. I simply have not heard other speakers that I can say compete with these on accuracy of tonality as long as the dynamic range restrictions are understood.

The fantastic tonality of the speaker remains constant with the speaker at any sensible listening angle. Stand or sit on the foor, it really does not matter much. I have never experienced this before and it is a direct result of the DSP system approximating a brick wall filter. Stereo imaging remained well defined over a wider than normal sweet spot. That is likely the result of the small egg shaped satellite keeping internal reflections low and the overall design of the satellite system to keep horizontal dispersion uniform across a wide range of listening angles.

What can we conclude from this? The days of the passive crossover are as numbered as those of black and white TV were when color was introduced. Purchase a $10,000 speaker with a passive crossover today and see its value drop to three figures on Ebay in three years. If you want to be the first on the block with the first real advance in speaker design since wide scale use of computer analysis and optimization, then this is your speaker."

[PEB]

Phillip - Out of curiousity, have you experimented whether the length of cables between your outboard xo and the speakers in relation to the length between the xo and the amps makes any difference? I can't imagine it would make much of a difference but then again stranger things have happened. I am thinking about making a box for my external xo's that fits on my rack so the wife won't dissaprove of extra boxes sitting on the floor.

Josh,
  That's an insightful question.  In my development technique, I happen to use driver harnesses (i.e. lead wires) that are a bit long for reasons of convenience.  The software modeling program essentially sees these connection wires as part of the raw driver impedance and SPL response.  Though the final umbilical connecting the external network will not be made from the same cable, the RLC difference must be miniscule.  
  Besides, the internal cable and external cable I use is quite lossless to the point that I have no concerns about the length on sound quality.  While I am much more particular about speaker cable construction (plus keeping the length short) than I am about interconnects, the cable I use is lossless enough that longer runs can be used without concern.

Though I have not had time to publish it at my site, I now offer a terrific bi-wire (4 in / 4 out) speaker cable that is high performance / low cost, to go with BESL speaker systems.  This cable is available for in-home audition, too.  I will use this cable for the umbilical.  It is round, and will just fit inside the Speakon lock ring if I push and twist hard enough.

Philip

[PEB]

The fantastic tonality of the speaker remains constant with the speaker at any sensible listening angle. Stand or sit on the foor, it really does not matter much. I have never experienced this before and it is a direct result of the DSP system approximating a brick wall filter.

John,
  4th order LR are popular passive network filters because one gets a good compromise between low parts count (= less veiling) with better tweeter performance (lower excursion) and woofer performance (less beamed and strained HF sound).

  To go steeper requires more parts and controlling the "dial-in" gets terribly interactive between components.  Going shallower may also not reduce parts count, because the parts may instead need to serve EQ duty instead of filter duty.

  Going (DSP) active is great because now "all" things are possible.  Delaying the tweeter means phase-twisting tricks (like mine) are no longer needed.  One can go steeper, because parts count is a non-issue.  The comb filtering in the vertical plane basically vanishes.  

  Of course, phase rotation continues to increase with increased filter order.  So I am very curious about what the DEQX can do with phase once I get my hands on one.  I have spoken to two reps from DEQX (who were kind enough to call), but it was not so easy to discuss what is possible and how over the phone.  

  I will be applying the capabilities to the Series 2 MTM plus XLS 3-way as a start, and then move to the S5-mtm-xls.  As far as brick wall, I remain skeptical, but apparently the linear phase filter begins at 8th order, and is not truly symmetric. No worries.

[Rick Craig]

Jim/Phillip/Rick,

Agree with you on the electronics/speaker balance for the most part.  It is easier, more wife accepted, and cheaper for the most part to swap a component than speakers.  I think this is why the marketeers have focused so much attention on the component du jour.

I just ordered a DEQX for my own hobby'ing.  I got some work left to do on finishing up my 6 channels of UcDs, but I have 3-4 weeks to wait before my DEQX is ready.  I'd love to get a jump start on learning by getting into th ...

That's great to hear. I think for some DIY's like you this is perfect because you can experiment with many different types of systems. What type of system are you going to try?

Rick

[John Ashman]

Just remember, I was just quoting $ensible Sound for Rick above, so that wasn't my quote, though I do agree with most of it.  The problem that you might have with the MTM is that you lose the excellent vertical dispersion.  It may be the line arrays are better because of the true cylindrical wavefront and the ability to stand up/sit down.  The difference with Xd is that the sound seems a little low when you're standing, but turns into a wall when you sit down.  A single mid can move as much air as two mids because of the steep crossover.  But if you want huge output, you can get plenty.  One thing I notice is that high volumes remain extremely clean and composed, right up to the limits of the speaker.  I think you'll have fun with DEQX.  Almost unlimited possibilities .   I don't think the crossovers are asymmetrical because the EQ makes the driver behave flat throughout the necessary crossover range and *then* adds the crossover, so it should be perfectly symmetrical.  Also, I believe you can do linear phase crossovers from 4th order and up now.

[PEB]

I'm already getting composed output at high volume from the MTM's now.  Going even steeper may help only a little more.  But I think steep is really what's required for ribbons, and that's why I haven't gone beyond the "What if" stage with ribbons until now.  OTOH, I don't want the benefit of steep DSP at the expense of "spitting out" the ribbon element at system turn on.  

For every pro there's a con.  And so it is with all things speakers.

[JoshK]

Rick - My idea is to DEQX my RM40s at first and in turn offer my experience to those here.  That said, one of the big draws for the DEQX beyond being a possibly great RC/pre/DAC is that it is a powerful development tool and measurement system.   I want to poke around building some speaker designs that intrigue me.  I am most intrigued currently with Jon Marsh's Arvo Park MKIII (orion/phoenix like dipole).   May mess around with a pair of line arrays too, who knows.  

John - I don't think you necessarily have to limit vertical dispersion with an MTM design, in fact done right shouldn't create any lobing at all.  Most commercial MTMs use too high a point and/or too shallow of slopes which creates the lobing you describe.  If the crossover is less than 1200hz then you have around 11 inches of c-t-c spacing before lobing becomes an issue provide slopes of >=4th order.  Many modern tweeters nowadays can handle this low of a point provided the slope is steep enough, which the DEQX also helps allow.  

Phillip - Many argue that steeper slopes are not needed or audible, this might be so, I just like the flexibility of doing whatever you want easily.  I think the advantage of really steep slopes might be when using metal cone drivers like the Dayton RS series, which are cheaper and competitive (supposedly close, but not quite) with the SEAS excel series but exhibit a much nastier break up.  

I heard from a number of experienced hobbyist that 4th order slopes well below break up mode were not enough to control the resonance, both audibly and measureably with the Daytons.  Without higher slopes a notch filter isn't needed, and I know many who utterly hate the sonic impact of using notch filters.   I am no speaker designer, I just like pontificating about the possibilities given such great technology.

[Rick Craig]

I don't know if this is redundant, and it might even be the clip I sent to DEQX that you read, but I had to type this in and the article is a long assed one that basically talks about the power of DEQX and then NHT's application of it, followed by the following salient bits:

The cabinet is molded from dense composite material that is similar to the solid surface material in your high-end kitchen. The satellites are acoustic suspension. This is the optimum design choice when matching a small woofer to a s ...

Thanks for the review information.

[Rick Craig]

Rick - My idea is to DEQX my RM40s at first and in turn offer my experience to those here.  That said, one of the big draws for the DEQX beyond being a possibly great RC/pre/DAC is that it is a powerful development tool and measurement system.   I want to poke around building some speaker designs that intrigue me.  I am most intrigued currently with Jon Marsh's Arvo Park MKIII (orion/phoenix like dipole).   May mess around with a pair of line arrays too, who knows.  

John - I don't think you necessarily  ...

There are three types of designs that I find really intriguing when combined with the DEQX : line arrays, MTM's, and dipoles.

[Rick Craig]

After all the posts Mac sold his DEQX on Audiogon  

[JoshK]

My guess is this was his first dEQX before he bought the one with the preamp builtin.  I think he still has the one with the preamp.

[Rick Craig]

My guess is this was his first dEQX before he bought the one with the preamp builtin.  I think he still has the one with the preamp.

Don't know - the ad said he was "downsizing".

[JoshK]

yeah I noticed that....don't know...

[zybar]

I have no idea about Mac, but I have noticed that many people bought the DEQX and sold it in a relatively short time span.

From what I have heard, the internal dacs aren't that great and it is not the most user friendly piece of gear out there.

It's tough to be on the bleeding edge...

George

[John Ashman]

The three main reasons I've seen that people have sold it are:

1.  Complicated to use and/or "what?  You need a computer?!?"  
2.  Doesn't do wonders with their poor choice of a speaker.
3.  Refusal to remove the passive speaker crossover, then realizing that you only get about 25% of the advantages unless you tri-amp.  

There are some people that have said the DACs aren't good which is definitely untrue.  The real problem was elsewhere, typically a refusal to use it properly.  Used properly with an appropriate speaker, the advantages are undeniable.

[JoshK]

What DACs are they?  I remember seeing it once but forgot.

[ted_b]

There are some people that have said the DACs aren't good which is definitely untrue.  The real problem was elsewhere, typically a refusal to use it properly.  Used properly with an appropriate speaker, the advantages are undeniable.

No, John, the DACS are not good.  I know it, Overkill knows it  (and said so on the 6moons review) and many others know it.  I, unfortunately, had to end up evaluating it as a pure dac since I could not use the room or speaker correction properly with the problematic speakers, nor the crossover capabilties.  In bypass I was simply eavaluating the dacs, and compared to what I have they don't cut it.

That being said, you don't buy the DEQX for its quality of DACS (Overkill uses it despite them; they're putting in their own), you buy it for its incredible digital crossover capability, FIR filtering, speaker correction and room correction.  But to imply that I "refused" to use it properly and don't know a good DAC is something I needed to reply to.  

I kept my word and made sure the DEQX was highlighted for what it is, and what it's great strengths are.  I continue to do that....it's a bargain at twice the price, if you use its full capabilities.  But to say the DACS are good, well, that's just not true where I'm sitting.  Heck, they don't even use it to anything more than 24/48 currently.  

Ted

[Rick Craig]

I have no idea about Mac, but I have noticed that many people bought the DEQX and sold it in a relatively short time span.

From what I have heard, the internal dacs aren't that great and it is not the most user friendly piece of gear out there.

It's tough to be on the bleeding edge...

George

Actually the two people I know that purchased the DEQX still have heir units; in fact, one of them is selling his to get the preamp version. If people are selling them I would like to know who because I've seen very few for sale on Audiogon.

In the two systems I've heard the Dacs were transparent and to me this is a non-issue. The guy who designed the DEQX also engineered the Fairlight synthesizer and anyone familiar with that keyboard will tell you the engineer knows what he's doing in the digital domain.

I agree that it's fairly complicated and for many users the simpler TacT will be a better choice; however, I've seen many TacT users also struggle to get the best out of their units. A background in speaker measurement and crossover design certainly will help but most of the owners don't have any experience in these areas. Product support is really important whether it comes from the dealer or manufacturer.

[ekovalsky]

It is not really fair to compare the built-in DACs of the DEQX (or the TacT) to good outboard units like the Benchmark or pricier units.  

Ted is 100% correct -- look at these units as sophisticated DSP devices that offer convenience DACs.  To get the best possible performance from redbook CD, buy dedicated external units or use amps with digital inputs.  Right now I am only aware of TacT/BOZ/Lyngdorf and Behold offering direct PCM>PWM amplification.  But later in the year Spectron will join the club, and others will undoubtedly follow.

If you have significant libraries of hi-res digital or vinyl, you are pretty much out of luck because of the required A>D then D>A stages.  I got into audio after vinyl was disappearing and have never had a turntable.  Although I dabbled in SACD I gave up on hi-res as both existing formats are dying. Unfortunately, I suspect redbook CD may be the 'hi-res' format of the future, with mp3 or other compressed media becoming the consumer standard.  This really isn't all that depressing -- I have a huge redbook CD collection and have been shocked at how good the TacT and Zanden (at opposite ends of the design spectrum) can be with it.  Maybe Blueray/HD-DVD will end up supporting hi-res audio, you never know.

The good news is with TacT you can save money by foregoing the DACs -- the base DD version (which I have) has all the DSP capabilities but is strictly digital-in, digital-out.  That said, I am looking for a DAC card for my unit to use with a brute force solid state amp on my subwoofer towers.  With the DEQ unfortunately digital outputs will cost you extra, but the DACs are already there if you need/want them.