bandwidth and sound quality

[Ben Hornsby <ben.hornsby@xxxxxxxxxxxxxx>]

Hello All,
I am looking for some references regarding changes in sound quality (in
specific speech sound quality but also music) with increases in lowpass
cutoff frequencies. I am especially interested about studies examining sound
quality in a background noise. I have found several articles discussing the
how increases in high frequency gain at a given bandwidth makes things sound
"shrill" but not any (yet) that talk about systematic increases in the high
frequency bandwidth and subsequent effects on sound quality. Any suggestions
are appreciated.

Thanks,

Ben Hornsby