Upper octave and lower octave room interactions seem quite different. One is a direct reflection that more or less preserves its waveform, so will be perceived as a smeared or reflected sound from the source (and not sure how you effectively dsp this because you're talking about reflections of detailed recognizable things.. vocals, instruments, etc), whereas with the latter the wave is often longer than the room, and are for the most part are truncated waveforms that manifest as unrecognizable resonances. These anomalies can be more imperceptibly fixed with dsp.
All that said.. even if you could effectively dsp upper octave room interactions.. who wants to listen in an anechoic chamber? That is a very dead.. boring listening space.
Dsp'ing transducers on the other hand makes some sense.. nullifying their unwanted resonances with the inside of the speaker cabinet and also leveling the direct output between drivers to give a flat output. Nonetheless, I am still suspicious of sticking sensitive DAC/DSP electronics into a noisy, vibrating space.. and also of speaker manufactures who also claim to be amp experts, and dsp experts. I don't think the company that makes the Holo DAC line wants to put their best work into a cauldron of strong magnetic fields.. a space that is literally shaking. I know it can be done, I'm just not sure if putting it inside, or attaching it to the speaker is a good idea.
I am still learning all this.. this is the way I understand it right now. I do own some small class AB active monitors designed by Simon Aston (Audiosmile/uk), btw. They serve a specific purpose, and I like them, but I don't nitpick their performance.
Some irony here is, the new (passive) speakers I chose (forgoing re-working my entire system and going the active route, but with separates) are designed by a music producer/studio engineer who primarily designs and manufacturers active speaker systems for his studios and clients.. this is how he makes his living. He's also designed very large line-array theatre installations for live performances. He's not a traditional audiophile speaker designer, however he still feels compelled to design and sell (albeit in very low volume) high-end passives. I'll have to ask him why next time. I still have this active digital crossover system in the back of my mind (but with separates), but just need some extra space to set up a second large system. I would like to see how good I can make it work.
