An addendum to my earlier reply.
By coincidence, someone reminded me yesterday that this has been done in the Official Audyssey Thread. The graph below shows dramatically the difference between Audyssey XT32 and XT, measured from the preouts.
"Red and green traces are XT32, blue is XT. Keep in mind that these are electrical measurements from the receiver's pre-out, not acoustical measurements with a microphone. Since the graph shows you what the filters are doing, you can think of it as the inverse of the frequency response (a dip on this graph is Audyssey pulling down a peak in the frequency response). Like looking at a negative of a photograph.
"Look at the blue trace (XT) and compare how little correction is being done in the low frequencies and how much is being done in the high frequencies. By comparison, the red
I tried, but couldn't find it.
Could you provide some boilerplate about what speakers, AVR, etc?
The measurement was direct from the AVR preouts so the speakers aren't relevant.
I think the speakers are highly relevant because the graph really makes no sense as it stands. Its meaning is in the context, which includes the speakers and their crossover points.
For example, if the center channel speaker were crossed over at 80 Hz, then any Audyssey function below that is far less important, and the crossover's action should be reflected in the charts.
This AVR has 2 sets of relevant outputs, the Pre outs and the speaker outs. They differ by the volume control setting and the transfer function of the internal power amps. Both of those are trivial.
We can't make the assumption that XT32 always does a more accurate job until we can establish that by other means. About the only thing I know for sure is that XT32 is a very different product from XT. It appears to be using a set of virtual parametric equalizers over the full frequency range.
XT appears to be based on an inverted Fourier transform above about 2 KHz and far fewer virtual parametric equalizers below that. It's trying to do something @50 Hz, but depending on the center channel crossover, that could be far less important.