Single most effective electronic room treatment?

I agree with the bass trap idea. Get at least four Aurelex Lenrd bass traps and put them in the corners of your front wall. This will improve things tremendously.

Very interesting and informative thread. One question -- rather than modding the TACT units, have any of you tried to use a very nice external DAC instead and then go to an analog pre-amp?

A special thank you to Jeffb28451 for one of the most thoughtful discussions on this issue. I've been trying to learn about -- and decide whether to take the plunge on -- a TACT unit for some time now, and this really helped.

I'd been an active bi-amping, straight-wire-with-gain guy for over 30 years, and was about nothing, if not transparency(I listen to live acoustic music every week, at least twice per). Colorations iritate me, no end. I'm now a devout TacT RCS 2.2X user, and can't consider looking back. The MauiMods power supply and unfiltered IEC assembly made a major improvement in the unit's transparency and dynamic potential. If you've not tried them: you've not heard of what a TacT RCS is capable. I've had Aurlex treatment in my listening rooms for years, and there's no comparison to what the TacT RCS can do. The Auralex DOES make the job easier for the TacT. The better the room to start with: The better the end result w/correction. The Tact will tweak your first arrival times and response to a "T". I use a DEQ-2496's 6th octave RTA, and the TacT's pink noise generator, to test the steady state response of the room. That combo gives all the flexiblity one could ever require for accurate musical reproduction(given a reasonable room/well resolving system to start with). Of course- your results are very dependent on proper speaker placement/choice, the ambience recovery/sound staging potential of the rest of the system, etc.

I owned the TacT unit, worked with it for months. While it made a difference in all the expected ways, it did slightly inhibit transparency. Some will claim that I must not have set the unit up correctly, or tried to settle for simple setup. In reality, I worked hard with the unit, and I am no idiot.

When the dust all settled, an expensive analog room treatment approach using 16 inch ASC tube traps and diffraction and absorption devices made the difference I was looking for. Sold the TacT, never looked back.

I don't usually do a follow up posting, but Egoss, like most folks, does not appear to understand active digital room correction. I admit, it requires a little thought, and there are other room corrections options besides the one I suggest, but active equalization for this purpose has nothing to do with tone controls, or the quality of the "other" equipment used or the modification of the "original" signal. It is more analogous to using an RIAA correction curve when playing a phonograph record. The exact point is to reproduce the recording as intended.

Two recommendations are to turn off your computer and refrigerator for serious listening. They are both free, and will make a huge difference. If you still have room problems, experiment seriously with speaker placement, or replacement. To buy an electronic device to cure your system's shortcomings is just plain wasting money. You don't mention what you have for equipment, but I suspect you're trying to make the Silk Purse out of the proverbial sow's ear. Just my opinion of course, but I'd rather buy music than another pice of equipment to get in the way of the original signal. But I'm just an old-school guy who enjoys his system without tone controls of any kind.
Best of luck in your search for more enjoyment from your Hi-fi.

I'm not affiliatied with TacT but,

Both assymetrical and symetrical rooms have their own problems: lack of balance in one and (more) resonance problems with the latter. I have a really bad, symmetric room with dual subs and balance/reflection problems due to (necessary) furniture and equipment placement.

Rives units are analog purist, but can only handle three bands AND ONLY EQ, not crossover manipulation, phasing, electronic location of speakers and subs to within fractions of an inch of "perfect" location, reflection problems and others. I haven't owned one, so I can't comment on their sound

I'm on my second TacT unit (2.2x with "whole enchilada mods by Maui MOd), as it deals with reflections, resonance and even phase and assymetry issues, not to mention INCREDIBLE crossover angles that simply cannot be done in the analog domain. Yes, I hate the DAC issues, but Mauimods can really put in some pretty good DACs. I've used expensive Levinson DACS, Nixon DACs, oversamplers, non-OS, etc. and these are pretty good.

Okay, guys, I'm a heretic. I have over $30k in analog gear that has to be converted and processed and every time I see a nice passive (like the silver Music Reference for sale right now) or even build a nice passive ($600 cost/parts for silver WBTs and silver wiring, naked Vishays (the good ones) on the shunt to ground attentuator, single input) my system struggles with an amourphous, lumpy sound

Everyone, audiophile and non, who hears the system goes "oh, ah", until I hit bypass. That it doesn't sound good is an understatement. I know, I could mess with speaker location (but I'm extrememly limited in options) crossover points, sub locations, etc) and even more tube traps and Aurex than I already have already tried) but I have to come to terms with audio systems: they are all full of compromise. The Tact DAC conversion requirement is the necessary evil I live with.

I look at it like this: I give up ultimate analogue transparency with horrible sound or get great tonal balance, flexibility and other benefits from the TacT, with a bit less resolution. My point is, I can't get good "music" in the room, due to boom, reflections, and phase issues, without it.

The down side: I only hear pure analog on my STAX phones (and yes, it does sound good) Analog purists must be able to hear though these problems (or else have truly miraculous luck with room shape and size), but I can't.

Something the analogue purists usually don't discuss and most don't even consider are the many and varied EQ curves used over the years by Columbia, DG, Angel, Phillips, RCA, Mercury and so forth. With the TacT you can build EQ to handle the EQ curves already present in your LPs. Without it, you're either using the newer and very few preamps with multiple EQ curves or you're not listening to your LPs the way they were meant to be played, anyway. Do you want DAC conversion prejudice to keep you from hearing the albums the way they are already EQ'd? If so, then you aint listening to your analog "properly" anyway.

Samu is right, esp about the learning curve for the TacT. I recently changed computers and had to reprogram some curves. I haven't done this in a year. I forgot a little bit. It took over 8 hours to get three curves rebuilt. The manual relates to the machine like a fish to a bicycle. HORRIFIC learning curve. It's worth it to me.

I have over $100k in the system now. 30 years ago, I would have thought that would buy me perfection. I know now that systems are compromises and the TacT makes those that I can live with. YMMV/flame away, analog purists.

Bass traps are a room's best friend.

The Tact has the capability to control room reflections and "flatten" response. The down side is that one must be patient and learn how to modify the "curves" to best advantage. Most of the unhappy users I have read about want to plug and play. They get little benefit. Another objection centers on the necessity of AD/DA conversion. With CD this not an issue.
Tact 2.0 is for sale on their site for $1500. I have owned one and also a 2.0S. Friends have other models which range upward in price and capabilities. I also have a Behringer Ultracurve, which while fun, is not in the same class.