Originally Posted by Nuance
John, if you are going to be rude take it somewhere else. There is no need for that. And stop with the wild assumptions. I agree with you on many points, but I still think it's unwise to purchase, especially one of that caliber, without having listened first.
Well, all I'm saying is that if you understand a design enough and trust the source, it's not always so dangerous. I've done a lot of educated blind purchases in my life and have rarely been disappointed. Just brought in PSB's new $2000 Imagine speaker sound unheard and was pleasantly surprised.
To prove there is no hard feelings, tell me more about DEQX. I already know what the technology does, but you say I don't understand (which I do), so please enlighten me. One thing I actually don't know is if it can be applied to any speaker in existence or only certain ones. Also, what's the price?
Okay, I'll try to keep it brief (ish) and apologies if I came to believe you didn't understand DEQX, but you did imply that it was simply a FR correction device used in conjunction with the speaker's own crossover. DEQX *can* be used as a simple FR corrector but that's not what makes it special. It's main purpose is to optimize the signal going to each driver and then use its crossover functions to blend them together after the drivers are behaving as close to idea as they can.
Crossover - 3-way 24dB-300dB/octave digital - this means you don't have to run a big signal though a bunch of capacitors, inductors and resistors. There's no heat/efficiency loss, each driver is hooked directly to an amp. There's no impedance based crossover modulation. No compression from heat build up in the crossovers.
Steep filter usage - If you increase the filter slopes, which isn't always necessary, you can get lower motor distortion from the midrange and tweeter as they work less hard at higher outputs. It also helps filter cone resonances from the woofer and midrange, giving them more resolution, less fuzz, less fatigue. But even better, it removes most of the audible acoustic interference between two adjacent drivers. The sound gets much clearer, upper midrange dispersion can actually be increased/smoothed and you can get a much wider soundstage and sweetspot at the same time.
Impulse response correction - This does FR/time/phase correction on each driver before it gets handed off to the crossover. This means that you can correct FR problems not easily or transparently correctable with passive crossovers and make sure that each driver is time/phase aligned so that it does not cause peaks and dips at the listening position from driver overlap, even without physically time aligning the drivers.
Here's a perfect example of an engineering problem from the $22K B&W 800D speakers. They want wide dispersion from a big driver, so they do the FST design which allows high frequencies to come from the center of the cone. I don't agree with that solution, but it is what it is. But then, FST can't move much air down low, so the woofers have to go high in frequency, well above the ~400Hz crossover. This means they have to use well behaved, low resonance drivers, rather than metal which was their stated preference. The FST also has a lot of color to the sound from resonance, so they either have to cut it off, going into the tweeter sharply, which creates a discontinuous sound, or let alot of that flavor in, but blend it over a longer range with the pistonic, low coloration diamond tweeter. They chose the latter, with a 1st order crossover - this means a high 4kHZ crossover to maintain dynamic range (or blow expensive tweeters). They go into great detail about the challenges of getting all this right, even in a $22K speaker.
Now look at the Tikandi. The W15 midrange has very great dispersion up into the early to mid 2000s, but gets a bit crazy near 5kHz absolutely berserk around 10kHZ. No problem, simply cut off the FR in the 2kHz-2.5kHz range at 96dB/octave and nothing about about 4kHz or so gets to the driver to cause it to misbehave. Now you have wide dispersion, wider and smoother than the B&W solution, but with far more resolution as it is very pistonic in the range it is handling, meaning very little resonance, just music. But now the tweeter has to go lower. But that's okay, because while the tweeter goes lower, it is much more protected from sub-2kHz frequencies because the filter is 16 times as good at removing frequencies - kind of like the Veyron which can beat a Ferrari even if the Ferrari has a head start. And the Tikandi's midrange can go much lower in frequencies because of the sharper crossover, which allows for the side mounted force cancellation subs.
So, the normal 3-way speaker gives up a lot - to get upper midrange dispersion, you give up low midrange quality or vice versa. In order to get dynamic range up high, you allow midrange resonances to creep in and dispersion to narrow, or to avoid that, you give up some dynamics and run the tweeter lower. You want resolution, but you often give that up to lower fatigue factor by using lossier, well behaved midrange and bass driver. Even if you keep up the dispersion, you still have dispersion problems in the vertical domain and lobing that makes the vertical sweetspot narrow and the reflected sound completely unnatural sounding. You want a driver that has flat FR but getting that, plus dynamic range and low resonance and other good behaviors is tough, so you have to compromise. And other stuff.
With a DEQXed 3-way, you can stop worrying about reasonable FR errors because they can be EQed before even hitting the crossover, perhaps a wonderful tweeter with an annoying bulge in the middle of its response. So now you can focus on low distortion, dynamic range and other important issues in a driver. You can take a high resolution driver that would be fatiguing in a low order system and get the resolution while chopping off the fatigue. You can run the tweeter low for wide dispersion and good integration, while still maintaining high output and low distortion. You can simply side step vertical domain lobing issues. You can use a very quick, very precise acoustic suspension driver that is higher or lower efficiency without having to padding down it or the other drivers to match and EQ it to flat down low. The drivers behave in a more linear fashion because there's no interactivity with the crossover. You can use very rigid drivers because you can ditch the resonance, which means that the sonic signatures of all the drivers are all lower and also more alike, which means a better blend even with sharper crossovers - there's little to no coloration to blend out - all while maintaining smoother dispersion in the horizontal and vertical domains.
In effect, you can have less compressed/more dynamic sound, higher resolution, lower fatigue, bigger sweetspot, bigger soundstage, better driver integration, higher SPL all simultaneously because you have more 'degrees of freedom' in the design process, some of which offer cascading benefits.
Now, taking any old speaker and DEQXing it (yes, any 2-way or 3-way will do), you can get better FR, generally +/-.5dB-1dB, improved dispersion, improved integration. Like my 20-year old Thiel project. The woofer just didn't blend with midrange and the sound was forward and tubby down low. Very easily, DEQX allowed me to lower the crossover region for the woofer/midrange, run it 10 times steeper with no added time/phase problems and get a seamless blend. Treble sounded better, but not that good, so I dropped some Morel tweeters in, soft dome unfortunately, but the only ones that would fit. Big improvement and easy blend. Ooops, I just ran my screwdriver through the woofer (yep, I did that), so I grab very inefficient NHT 10" woofers and drop them in. Crossover comes down a bit, the woofers get jacked up about 4 or 5dB to make the proper blend, but another huge difference, now we actually have a lot more wallop down low. This 20 year old Thiel now would devastate a brand new Thiel, certainly in terms of resolution, sweetspot, low fatigue, enjoyability. I did a B&W 602, a speaker I've never much liked. Now suddenly it's better than every other 2-way I sell. Smoother, more integrated, more resolving, decent bass for a change and actual imaging/soundstaging. Even B&W fans are blown away by the difference. Etc, etc, etc.