First, as I understand Audyssey does not eq in pairs. It’s a FIR filter based correction system that separately shapes the response of each speaker. It is considerably more complex than the basic types of eq we normally use. In general it is a bad idea to use minimum phase filters to fix the response of a speaker above the transition frequency of the room, as amplitude and phase/timing are not locked. You can fix the amplitude only to muck up the phase. What this means is that it is impossible to use a minimum phase filter set to fix the response of a speaker as it will be only right in a tiny space, and wrong everywhere else. The fix to this is to use a special inverse impulse filter that corrects the response for both phase and amplitude and relies on a weighted average over a larger listening window. This is only possible with FIR filters. That means that it is not possible to understand the filters as a simple set of frequency, Q, and amplitude sets. That means it is not possible to give average users control over the filters or even to explain the filter. We typically see responses as peaks and dips in the amplitude and most people ignore the timing/phase issues. An FIR filter is best displayed as an impulse response and most people can’t read those usefully.
The new editor is a great addition because a lot of people don’t like the factory set target curves. It also gives us a lot more information about what is going on with each speaker. Unlike DIRAC, it was hard to know what curve was being used, what corrections made, or how it measures our speakers. While the filters can't be seen, we can at least see before and Afters.
The one problem with Audyssey is that it uses a filter type that is very processor ineffecient at low frequencies. FIR filters are measured in taps and it takes more taps the lower in frequency. While Audyasey restricts the tap usage by octave to avoid the problem I'm about to mention, it none the less it limited in the resolution it can control at low frequencies. Since low frequencies are minimum phase and steady state (the same everywhere in the room, all variations can be attributed to room reflections and resonances) you CAN use minimum phase filters. It allows for correction of time and amplitude correctly and by the laws of minimum phase it also automatically fixes ringing, the main problem with modal resonances. It isn't perfect and in fact well below the schroeder frequency there is evidence in small rooms of stochastic behavior meaning what I said won't be true, but it's generally ok to accept it as true. Just don't think EQ can replace room design, speaker position, or acoustic treatment.
What this all means is that for some of us we can support Audyssey's own corrections by making our own corrections first. This gives a massive effective boost to our rooms of correction filters and allows a far flatter response. It also allows EQ of response areas too low for Audyssey to efficiently touch (some people like a room that is flat to 5hz for example). Many of us use amplifiers with dsp or external dsp like Mini dsp. We generate filters in various ways, but I think the most common is to use REW's ability to generate filters for us with amplitude, Q, and Frequency. We then plug them into our dsp and go. To do this we need to take measurements and design our filters from that. I think everyone has their own preferred approach that makes them happy. There are a lot of tutorials of how to do this. I personally use one measurement at the MLP for all distance alignment and use the alignment of the impulse response to do this. I use averaged measurements of my MLP and other listening positions to set eq. That way I apply eq only to those frequencies that are consistent over a wide range and avoid eqing things that are very position dependent.
After I have set the distances and alignment using my dsp and the receivers built in bass management I then run Audyssey. I then usually undo the automatic bass management settings it comes up with and restore them to what I want. I take more measurements. I then do final eq to tweak. Take final measurements and call it a day.
Big take away, full manual correction is my preference at low frequencies, but nobody should be really touching the frequencies above say 200hz with eq unless they really are experts in filter design and really know what they are doing.
For what it’s worth Ealr Geddes and Floyd Toole are both huge proponents of room eq for bass but both think that any form of room correction above the bass range is a bad thing. They strongly believe that it is simply not possible to correct for the room at those frequencies and that speaker design, setup, and room treatment are what matter. I have found problems with Audyssey correction in the midrange and do think my speakers sound better and image better with it off. I don’t find that true of DIRAC. Worth noting that I don’t have XT32 which is supposed to be a big improvement.
Sent from my iPhone with a keyboard that predicts what I mean very poorly