I get a chance to experiment with other's equipment on a regular basis. And room equalization is more than a hobby for me, as I have been working with musicians, designing studios and clubs since the mid 80's.

While Symetrix does a great job with phase coherence, I have been looking at the new Behringer "Ultra Curve Pro 2496" as something new to try out, it is a 24 bit/96kHz digital processor. And two (2) SHARC 40bit processors for internal number crunching. If this thing works... half as good as the hype, wow... for $300 you can put a lot of tools to work for both big and little rooms. I have clients who are using it now, and have been astounded by it's price/performance ratio. Sound like some other audio equipment you've heard of?

We do analysis of the sound profiles of rooms at different positions. For a paying customer, or a tempermental musician, the sweet spot better be bigger than the head of a Callaway driver. We have found that if you just pass the high frequency (HF) signal (above 350 Hz) to the amps, the spacial information is often much better rendered. We usually can find architectural methods of shaping the HF sound profiles in rooms that work well.

For live music, track specific EQ, and other FX (effects) can be applied before summing at the mixing board. After summing, the signal can go to the active crossover network and specific room EQ is applied to the low frequency (LF) signal. This way, you EQ the room separately, and the musicians and sound engineers can play with all the knobs and boxes they want without changing the room EQ settings.

For my home, I only EQ the LF signal, and with great success. We have done extensive measurements of phase shift and frequency response. To do this well, you can not rely on a 1/3 octave tone generator and 31 band equalizer, as 1/3 of an octave is just too broad to get accurate measurements or good EQ solutions. There is PC software available that compares very well to the best sound analyzers. Try this site; http://www.trueaudio.com (available for $100) for example. This provides up to 1/24 octave measurements with great accuracy. I have compared the results to the $8,500 pro gear we still sometimes use, but the overall diagnostic ability is just as valuable.

So this is the principal reason why I bi-amp my main speakers (B&W N803's with an internal passive crossover); to achieve speaker/room EQ for LF, while keeping the HF signal clean, simple, and SPATIAL (a wide and deep soundstage with a big sweetspot). I will probably try a valve amp for the HF to try to hear what so many in the "tube community" have been trumpeting.

Anyway, it works for me, and I believe this technique could potentialy make a positive contribution to many other's systems as well.

Thanks for your post,
Allan

[This message has been edited by AGAssarsson (edited August 27, 2003).]