[old_tv_nut]

This is an interesting topic to me. I think professional musicians can be poor judges of sound reproduction because they can fill in missing stuff in their heads - but that's just a wild surmise, because my musical experience consists of 4 years of playing second clarinet in the high school concert band.

As far as tonal balance of bass and treble in systems with limited bandwidth (like AM radio), there was a rough rule of thumb that the low frequency and high frequency cutoffs should be balanced, that is, a system without extended highs should also not have extended lows. I think there was even a rough calculation that the product of the low frequency cutoff and high frequency cutoff should be roughly a certain value, but I don't recall the details. I don't know how this affects old guys like me that are losing their high frequency sensitivity, but not their bass sensitivity. We are probably doing a mental (psychophysical) compensation and just hearing less of the difference between AM radio and HiFi.

I also want to mention that some distortion of mid frequencies can generate synthetic highs that make a speaker system sound like it has better high frequency response than it really does (if it's not too extreme). This was common in the small speakers in TV sets. A side by side comparison with a system with real high frequency response will reveal the difference, however.