At one point used DRC Designer - a room correction software working in both the amplitude and time domain - over my previous, passively configured all-horn speakers. At the same time at had those speakers high-passed, digitally, just below 80Hz in conjunction with a pair of tapped horn subs (that I still use with my current speakers), so: 3 filtering processes overlaid, incl. the passive XO.
Anyway, DRC Designer was a sonic double-edged sword; on the one hand it made for a flatter and more decent/"correct" presentation with more extended HF and a resonance suppression at ~125Hz in particular. On the other hand it took a "shine" off the sound with a mildly bleached/stale and even sterile imprinting. I finally realized that I wanted my main speakers and overall configuration to be something else, finding it better to just leave those main speakers play full-range as they were (preferably with an SET), flaws and all and great qualities as well, without subs augmentation. That, however, wasn’t where I was heading.
What I have now is fully active with only a single element of filtration, namely a Xilica digital XO/DSP. No room correction or passive XO parts of any kind. We’ve measured the HF/MF horn in each channel, near field, to address slight frequency response irregularities with a few mild notches and a single (also mild) peak suppression. Everything wrt. to the chosen values of gain and Q here, as well as the remaining filter settings, has been done by ear in the listening position over a period of time. Delay adjustments was the last, major area in the tweaking process, that are sometimes revisited (in conjunction with speaker positioning) for minute adjustments in the wake of changes elsewhere in the chain, should they occur.
