I just had an idea, I was wondering if its been done and tested before.
if you take a sample, and resample it to half - then you lose half the frequencies because they are now above nyquist (theyve lost their compression or rarefaction.)
that will give you a low pass filter.
you shrink the sample set to lose the his- then you reenlarge it to keep it in the same time set.
then to get a high pass filter its the original sound minus the lows, and a
band pass is a lowpass filter and highpass filter combined.
so you could actually make a filter library out of resamples, and its actually not computationally expensive, and it
has instant reaction - and iir and fir filters take a few samples to kick in (the higher order they are the more they
woomph the sound in), so this is actually better in a way!
to get so theres no distortion, youd have to implement anti aliasing.
is this a valid way to make a filter?, or is it not accurate enough to work properly. and has it been done before?