Struck's approach is basically an adaptation of the
Hopkins-Striker equation, which allows the calculation of net sound power in a field including both direct sound and reverberation - because the absolute level isn't a concern, his output basically serves as a way to average between two HRTFs/frequency responses based on some known parameters. One is a free field HRTF (0 degrees, 30 degrees, whatever), representing the "direct sound", and the other a diffuse field HRTF, for the reflections. The weight in the output assigned to these two HRTFs/FRs is based on the reverberation time of the room used in the model, and the directivity of the speaker.
So in other words, if Amir has:
1: A free field HRTF (or a group of them for an average, although I'm not entirely sold on that pitch)
2: A diffuse field HRTF (you can synthesize one of these from free field data if needed, btw)
3: the reverberation time characteristics of the Harman room (which he does)
4: the directivity characteristics of the Revel speakers Sean used (should be possible to find, I'd think)
He can use Struck's methodology here to "simulate" the Harman room, in premise. Neat concept!
Interestingly, my understanding of human HRTF adaptation is that this shouldn't be too much of a subjective change - once your brain rebuilds the "HRTF library" it uses to attribute localization, I'd expect subjective timbre to be relatively constant.
Eyup - I mean, at the end of the day, these are all just ways you can look at the behavior of a system by comparing two inputs. ARTA's been able to do this for years, and it looks like
Audio-Precision added it a year or two back, and of course Temme referenced it in a paper for B&K back in the 90s to my memory. Not a terribly high-tech trick, but it gets applause at parties, and there's some evidence to support it being a preferable test methodology for transducers.
Plus, it's a nice thing to have in your bag of tricks for when people say "But you just tested with
sine waves, and
sine waves aren't
music".