Earl Geddes did bring a lot of interesting topics to the table for sure!
One I find very interesting is the instantaneous thermal compression that he classifies as a distortion, calling it "thermal distortion".

Although the 2.7sec he is using is way too long to fit Earl Geddes' definition, Erin's "Instantaneous Compression Test" is pretty discerning already:
M2: https://www.erinsaudiocorner.com/lou...mpression-test
708p: https://www.erinsaudiocorner.com/lou...mpression-test
305p: https://www.erinsaudiocorner.com/lou...mpression-test

That is an area where compression drivers and big woofers do shine