DEQX - TACT - QOL - Thoughts on these?

I used DEQX at shows in the past and I modded it for customers. They actually adopted many of my mods in the latest unit. What I found is the best way to use it is with the internal DACs. Going external was problematic for me. I used it once with 2 external DACs at a show. Things got crazy when I tried this. The automated speaker and room correction failed to work and the programming got changed magically by itself. I dont think many customers actually use it like this.

DEQX is still the best crossover box out there IMO.

I use EQ with Amarra on my Mac. Now this is totally transparent and transforms even the most expensive systems. Unfortunately, crossover using a server is still very difficult and expensive.

Steve N.
Empirical Audio

I've just got ot chime-in to this old thread to counter Steve's experience above. I've had DEQX HDP-3s and always used them with external DACs, and never experienced the issues he described - never. The internal DAC is not "bad" but one can do quite a bit better. The conventional wisdom that the extra ADC stage would be a large detriment does not seem to apply - at all.

I find the room correction the least important feature of the unit, by a longshot. The steep, linear-phase crossovers and time & phase alignment can (and normally do IME) give results I would call "stunning". Then there is all the parametric EQ one could want. If one is DIYing a horn system, with PEQ and time-alignment necessary, I think it is impossible to do better with analog xovers, passive or active.

When properly used, the unit is completely transparent and does not have the slightest hint of anything "digital". (I think anyone who heard the Cogent True To Life field-coil horn system at RMAF 2006 would attest to that.)

I would like to present a dissenting view.

I have heard DEQX systems on a few occasions - ho hum. I am looking to hold a GTG down the line comparing it to a SOTA passive - the reports I hear is the passive MURDERS it - but we will see.

I have a QOL and nearly everyone I demoed it to agrees it makes a significant and positive difference. I cant live without one these days.

Thanks
Bill

One thing that's for sure is that it is highly possible - perhaps even likely - to have a DEQX-based system sound terrible, in multiple ways. Measurement and using the calibration software correctly are everything.

I second Paulfolbrecht on DEQX HDP-4 unit as I have one. I tried TACT 2.2 XP which was very limited, no linear power supply, and buggy. Tried Accuphase xover, Marchand XM44, and even designed my own passive xovers. None of these even comes close to what DEQX HDP-4 can do. It measures and correct each speaker driver component in a multi way active system. Then you can specify any xover frequency points and slopes from 6db/oct to 300db/oct linear phase or choose Butterworth or Linkwitz-Riley. It can then time align each driver and correct for room response. The SQ has no trace of any digital signature in the resulting analog output and results are just phenomenal. The problem is most people don't know how to use all of its features correctly.