Very nice feedback, especially from our "skeptic's skeptic"! Kudos for trying! Yours is the kind of response that should get people thinking. I presume your friends found it worthwhile. "Vast improvement" is an accurate description, not exaggeration.
Elizabeth, I have changed resistors and caps on the PureAudioProject Trio15 Horn 1 Speaker with nice results, as well as the "internal wiring". So, I'm not surprised that there is a difference in doubling resistors.
maplegrovemusic, if you have not read my article on Schroeder Method at Dagogo.com, and associated discussion, you should. At this time there are certain precautions in place to prevent potential problems with unknowns, i.e. not at this time recommended for class D amps. Do not go blindly into a "do at your own risk" activity. To do XLR Schroeder Method you need standard Y cables to double the cables, then a pair of what I call "reducing Y cables" that are double female to single male. Most that are found commonly are garbage, and sound accordingly. Audio Sensibility (under review) has the normal Y cables for XLR, but has added the reducing Y cables for XLR due to Schroeder Method.