I have been disappointed by this round of Room Correction with Tact. It very much looks like I cannot do a decent room correction without setting up a target curve which is pretty close to my measured response. I suppose I could do that, but I am not so motivated anymore. It is clear that the correction I used last year was leading to excess room boom at 45 Hz and other problems. Now I have heard how a simple correction can lead to very undynamic sound.
Instead, I am doing what I have long done with my bedroom system, applying manual parametric EQ adjustments.
Starting with no EQ or RCS, I do find that the primary room nodes 38-50Hz are turned up slightly (though this is HIGHLY position dependent, and one can even get cancellation nearby). So a manual EQ should cut this back slightly. I am using the 6dB cut of Tact Parametric EQ #1, but maybe should roll this back a bit since it may cut too much at the listening position.
Also, a manual EQ should attempt to improve the 100Hz-200Hz depression. I think at least part of this depression is caused by frontwall cancellation, also maybe partly by dipole cancellation. My strategy for fixing this is to use multiple staggered small EQ's. I have started with 2 corrections:
140 Hz +2.2dB "octave width=0.6"
125 Hz +2.2dB "octave width=0.3"
(I have programmed these into Tact EQ #1. The Tact allows you to select "octave width" instead of Q. It is nice to be able to select EQ's by remote control.)
The above EQ's have about the right effect, increasing the 100Hz-200Hz response for a pleasant, if not perfect, correction, in combination with an EQ at 42 Hz. The attempt is to make a broad pleateau in the electrical response from 110-180Hz, with the plateau getting taller as we get down to 120Hz (but avoiding peak stimulation of the potential resonance area at 116 Hz). It is often said you cannot correct deep depressions with EQ. That is true, but you can ameliorate small depressions.
Using these EQ's, the outside of the listening area has much less "boom" than last year, but there is still some boom in the corner near the Kurzweil.
With the EQ's, the sound is very sweet. It is one of these paradoxical effects that improving the midbass seems to improve the mid highs.