Thanks for responding.
A few comments about process.
First, this is an iterative process, not an all in one do everything at the same time operation.
First, the crossover issues is to resolved and corrected. It is not some step in the room correction process.
And a NECESSARY part of the crossover configuration is the signal alignment of the sources.
Please describe the issues apparent with the crossover. My apologies that it is not clear to me that there are issues by looking at the measurement results.
My mains are capable to 40 Hz, so that is not a limiter. I took sub+mains sweeps with the crossover at 40-80 Hz in 10 Hz increments. A crossover setting of 70 Hz produced the visually smoothest response (with no or at most 1/24th smoothing).
What is the proper method for determining the crossover frequency? I will gladly read a reference source if you could point me to one.
Phase alignment of sub to mains: I have read of a few ways to do this. One is using the group delay plots, but these are usually too noisy to properly judge at the low frequencies a crossover is at. My experience was similar.
I adjusted the sub phase until the sub+mains SPL was loudest when playing a sine wave at the crossover frequency (70 Hz). Comparing frequency sweeps at 0, 90 and 180 degrees confirmed 180 gave the visually smoothest results.
Again, I would gladly read a reference source for the proper way to do this if my approach is not appropriate (e.g. I'm not trying to ask you to write paragraphs in response - I recognize responding in detail is time consuming).
After that is done, then focus on the modal behavior.
And please loose the FR smoothing. We are not trying to sell this or to make things 'look' nice. Instead we WANT to know the detailed issues that are obscured by smoothing! (Sorry, not angry with you, but seeing this predilection with smoothing remain an almost universal fixation with folks who claim that they want to identify and resolve problems in the process of obscuring them grows old...)
First map the space. The mapping of the region can be done via waterfalls, or if you are not comfortable with this, perhaps more easily by the playing stepped tones (in REW) in order identify modes and to then identify the location of regional peaks and nulls. Assuming L/R symmetry, explore the region about the desired listening position, both forward and backward from the current position, in order to determine the location least subject primarily to modal nulls, and then to a lesser degree to peaks. A problem avoided by relocation is much easier than attempting to utilize brute force.
Then you will want to employ 'pink fluffy' Superchunk style porous corner traps featuring 6mil or greater faced fronts. And then after bass traps are installed and the space remeasured, one may then choose to employ limited EQ to mitigate the PEAKS (only, and then only up to 3dB) for modal peaks below 80 Hz.
Heh, I understand your frustration with smoothing. I only used some because otherwise the High frequency response is unusable; 1/3 seems to be standard for above ~250 Hz and below that none or 1/24th? I guess I should have broken it into 2 different plots.
I did this when selecting a location for the subwoofer but limited myself to the frequency response graphs. Will this not show peaks/nulls?
I have not experimented with relocating the mains. I will do so. I also have port plugs coming that will grant more placement flexibility for the mains (they have a rear port).
Unfortunately, bass traps are likely a no go. This is a multipurpose space, not a dedicated theater and the WAF is not there.
After all of this is done, THEN individual ETC responses are derived for each source.
You will want to resolve each of the high gain sparse indirect energy arrivals into their vector paths and point of incidence.
A couple quick observations about the ETC above....aspects that can provide a quick indication of potential issues.
First, is the direct arrival REALLY at ~35 ms, or 39.6 FEET from the source speaker?!? I suspect not.
Thus, depending upon the method you intend to use to resolve the vector paths, you might want to consider using the hardware loopback correction for system propagation delay so that the arrival times displayed are accurate.
Also, you have quite a few significant sparse (isolated) high gain 'reflections' relative to the surrounding space, as well as a at least 4 Very significant late arriving indirect returns.
But becoming overly concerned with specifics aside from the basic configuration of the ETC process at this point is premature. Now just focus on configuring the platform in anticipation of the measurements to be performed with the mic remaining in the same precise position (a position 'marked' so that it can be Precisely re-established at any point in time later).
I was using a loopback cable. The receiver has 14' distance for the mains in it (which matches the distance measurements), but even with that (14' receiver delay + 14' actual propagation delay), as you indicated, it does not add up to 35 ms. I should have noticed this and investigated. Perhaps I was using the loopback incorrectly. I'll have to play with this more when the time comes.
Regarding mic position, yes, I will have to break out the plumb bob and painters tape as you advised in another thread.
Also, when you do post results, please post the REW .mdata files.
It was attached (hence my references to it in the text).