5 ms·
While Schroeder's algorithm sounds like reverberation, these days it might not be confused for 'natural sounding'. Well, to be fair there is worse sounding rev
by dspig 9y ago
While Schroeder's algorithm sounds like reverberation, these days it might not be confused for 'natural sounding'. Well, to be fair there is worse sounding reverberation in real life (garages).
A better sounding algorithm is to convolve the signal with decaying random noise - impractical in Schroeder's day - but that's sort of what his and later algorithms are approximating.
Edit: Improvements on Schroeder's algorithm include feedback delay networks (where the comb filters don't just feed back to their own input, but to the others too, and/or nesting allpass filters inside each other. Both of these increase the density of echoes faster.
- bch 9y agoDoes that mean convolve (e.g.) white noise w some decay model (or apply adsr envelope?), and then again convolve your subject w that resultant decayed random noise? Do my definitions for “random” and “decay” even fit your thought?
- dspig 9y agoYes, take a few seconds of white noise, apply an exponentially decaying envelope, and convolve with the input signal. Of course there is a lot more you can do: high frequencies decay faster in a real room, the envelope could be a more complex shape, or just skip to near-perfect and convolve with an impulse response measured from a real room.
- bch 9y agoThat’s exactly how I was interpreting your original post, but I had to confirm. The impulse response (real or constructed) was my first thought too... this all sounds intriguing, and it’s a synth day for me today ;)
- tzahola 9y agoWhy does white noise work? Is it because the spectral density of both the Dirac impulse and white noise are flat, and our ears don't care about phase?
- dspig 9y agoIt doesn't have to be white - pink noise works the same just sounds more muffled/bassy. It's more that there is no distinct pattern in the time domain for the ear to pick out, which would add echoes or metallic ringing. The same as a boxy room or shower cubicle will ring/resonate at certain frequencies, but a bigger more complex shaped room will have an effectively random pattern of reflections for a given source and listener position.
- regularfry 9y agoIt's simulating a randomly distributed set of acoustic reflectors. Well, ish. Makes it sound more like a room with stuff in it rather than being in a box.