What does a bypass cap actually do?

[mingram1234]

I've been told that bypassing crossover caps with something like a .1uF good quality cap would improve on the sound of the system as a whole. Is this true, and if so just what/why does it do so?

Thanks,
Mitchell

[madmax]

A bypass cap shorts high frequency garbage across it's path. For low impedence stuff like speakers I see no reason why it would help but certainly it can't hurt anything. If anything it could help upstream of the speaker but through any length of cable it couldn't even do that. Who knows, maybe it could help some minor cap characteristic problem. It would be interesting to hear what their theory is behind it.
madmax