Subject: Re: [linux-audio-user] Pitch shifting
From: Remco Poelstra (rjpoelstra_AT_home.nl)
Date: Mon Jan 28 2002 - 20:02:56 EET
On 2002.01.28 16:42 Steve Harris wrote:
>
> Maybe. Its common to think of pitch shifting in octaves/semitones, so a
> +-12 semitone scale might be better. You could probably assume equal
> temprement:
>
> s = 2**(p/12) [s = pow(2.0f, p * 0.0833333333f); in c]
>
> where s is the scale coefficent and p is the pitch shift in semitones.
>
Thanks for this formula, it saves me a lot of math :).
> Ofcourse I could make the LADSPA interface semitones if people preferred.
> I was thinking more of an SL2's +-n% when I wrote it.
I think semitones is very usefull, because when doing pitch shifting your
are mostly working with music, thus thinking in tones.
Seems that previous time, I've only seen the 'normal' pitch shifter. This
indeed does a very good job! I've been using Goldwave to do the pitch
shifting until I got these mails and compared both. With Goldwave (with
settings: FFT size 11, overlap: 95% ) it takes hours (well, a very long
time) and it produces artifacts in the higher registers. '1194' produces a
bit wah-wah in the lower registers and the voice seems to have some
multi-tap delay, but the real-time and linux usage takes away any doubt on
using this solution.
In short: Thanks for this great plugin and pointing me on the high quality
version!
Remco Poelstra
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