MOTM

Invert the output of your LPF and mix it in equal proportions to the original signal. The lowpass'd signal will cancel out the low portions of the "dry" leaving higher frequencies.

This will only work if there are *no* changes to the phase of the audio 
that's been filtered.  I think that some
of the interesting effects of some filters are due to phase changes in 
various frequency ranges, and how they
interact with each other.

But I just woke up, so...

-Geoff

Tkacs, Ken wrote:

> Invert the output of your LPF and mix it in equal proportions to the 
> original signal. The lowpass'd signal will cancel out the low portions 
> of the "dry" leaving higher frequencies.
>
>