Following the comments regarding the exponential modulated noise segment; My experience is that all such actual segments will be spectrally coloured, because of course they contain a truncated set of random values.
The only theoretically "flat" exciter is the Dirac impulse. But because it contains so little energy its not that practical for stimulating waveguides. Better to construct a band-limited pulse from a finite set of sinusoids right up to the Nyquist. A problem is this will have a finite rise time. A practical compromise I found is to use the exponential decay segment, as it is, without a payload, and make it jolly short. I guess as T -> 0 the behaviour tends towards the Dirac pulse, but where T is just a few tens of samples it works as a very clean, reliable exitor for waveguides. (Indeed this is what you have in a lot of analogue percussion synthesis) Perhaps someone can show you what the spectrum is as a function of T, its not "flat" but its a good trade off between a theoretically perfect impulse and a practical signal. cheers, Andy On Wed, Jul 27, 2016 at 07:00:02PM +0200, gm wrote: > > Hi > > I want to create a signal thats similar to a reverberant knocking or > impact sound, > basically decaying white noise, but with a more compact onset > similar to a minimum phase signal > and spectrally completely flat. > > I am aware thats a contradiction. > > Both, minimum phase impulse and fading random phase white noise are > unsatisfactory. > The minimum phase impulse does not sound reverberant. > > The random phase noise isn't strictly flat anymore when you window > it with an exponentially decaying envelope > and also lacks a knocking impression. > > I am also aware that a knocking impression comes from formants and > pronounced modes > related to shapes and material and not flat, which is another > contradiction.. > > I am not sure what the signal or phase alignment is I am looking for. > > Also it's not a chirp cause a chirp sounds like a chirp. > > What happens in a knock/impact besides pronounced modes or formants? > Somehow the phases are aligned it seems, similar to minimum phase > but then its > also random and reverberant. > > > Any ideas? > > > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp >
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