🚀 go-pugleaf

I've just implemented a vocal eraser (thanks DAn) but have noticed one 
main problem. When I cancel out the vocal (usually dead centre), it tends
to cancel out the bass as well.

Since bass is usually at lower frequencies than vocals, would it not
be possible to filter out the bass parts of the stereo signal (hopefully 
avoiding nearly all of the vocal) and then add this back to the (monoised)
vocal cancelled signal. This would (theoretically) add some stereo width
back to the signal.

Can anyone suggest a suitable frequency cutoff (in Hertz) for a low pass
filter to filter out the bass parts of a music signal?

What about a high pass filter, what are the highest frequencies present in
a lead vocal? Are they low enough so that there's useful stuff in the higher
frequency ranges (I'm using 48Khz sampling, and processing output from a
CD player).

Thanks in anticipation,

Ross-c