For people who don't fully understand or don't trust the rational explanation, it's easy for the placebo effect to create perceptions of differences where no di

For people who don't fully understand or don't trust the rational explanation, it's easy for the placebo effect to create perceptions of differences where no differences whatsoever exist in reality. So in terms of marketing snake oil to suckers, I disagree that a bright line exists between small-but-measurable and not-measurable. The human tendency towards irrationality is very strong, easily capable of swamping small differences. I'll also say that it's not so much the hard-to-measure effects where you need to spend your time when pursuing accurate reproduction. Speakers have much poorer fidelity than anything else in the reproduction chain, and room acoustics matter a great deal (especially having a large enough room with high enough ceilings, to increase the ratio of direct sound coming from the speaker vs. reflected sound). The contributions of these factors are not small but they are are hard to understand, assess, and apply in practice.