whereas orchestral recordings or recordings with
amplified instruments can cover a lot of sin.
Exactly. If you can't follow any instrument of your choosing on large orchestral
or big band (due to their being too much going on) then that indicates a poor
quality system. A good system should uncover every sin on even the busiest
recording. It is an awful lot easier for a system to play one small instrument well
than to play a big band that fills the entire audio spectrum at high SPL and still
sound as if each instrument is being played individually and effortlessly.
So beware the salesman who sells you a speaker based on *only* listening to
Diamonds and Rust by Joan Baez - you should check to see how the speaker
handles a busier recording first.