I’m working on a thing where I’m planning to take a soundmass and split it into vertical / spectral parts – for example, a slice from 0-100hz, 100-300hz, 300-600hz, 600-1000hz, 1000-5000hz, 5000-10000hz, 10000-20000hz, or something along those lines.
(Then do various time-based etc processing to each layer to taste)
The approach I’m taking is to include an overlap/bleed between sections, with a bleed tuned so the basic reconstruction when stacking the sounds back together is reasonably transparent. Eg, no audible notches at the seams. For my project it’ll be nice if the original sound can reassemble untreated, since I just want to do things with the splits sparingly.
That’s the plan anyway. It seemed like a reasonable topic for discussion, just curious if you all have approaches to this sort of thing that you like – filters all the way! analysis/resynthesis all the way! etc – or find a set of tools or particular workflow useful when operating on vertical slices of the sound spectrum like this.
My filter tool of choice for this particular project is just going to be sox, but if I don’t like the results I might give SPEAR a go and get a little more creative (and manual) with the slicing.
(Edited because I used the word horizontal to describe a vertical stack of frequency bands. Derp.)
Here’s the dumb little python script I made to split a soundfile by a list of frequency breakpoints:
bands = [100, 300, 500, 1000, 3000, 4000, 6000, 8000, 10000, 15000, 20000]
overlap = 50
inputfile = sys.argv
outfilebase = 'bands'
lowfreq = 0
for i, band in enumerate(bands):
highfreq = band
if lowfreq > 0:
lowfreq -= overlap
subprocess.run('sox %s %s%s.wav sinc %s-%s' % (inputfile, outfilebase, i, lowfreq, highfreq), shell=True)
lowfreq = band
Save it as something.py and then use it by calling python3 something.py yoursoundfile.wav
Requires sox of course!
Tweak the list at the top to change the breakpoints…
Actually this seems fine for my purposes at the moment using just a fixed 50hz bleed. I thought I’d have to tune it a lot but the sound I’m processing is a big ole slab 'o drone so it doesn’t reveal the artifacts of this process as easily as I thought I guess…