I would have thought it fairly easy to devise a test to check if vibrating a cable caused any change in the sound coming out of the 'speakers. Put the 'speakers in one room, the equipment and/or cables in another isolated room and then vibrate the cables either physically or by subjecting them to local sound. An objective answer should result. Depending on the result, further investigation might, or might not, be necessary.

Perhaps I should confess to having a rational attitude in these matters.

Locus.