Re: vocal pitch correction toolkits

Martin Drautzburg wrote:
Dear all

I've been looking for a free vocal pitch correction software or toolkit
for several weeks now, bit there does not seem to be anything. I am
even willing to program the stuff myself if I find a decent toolkit, so
I don't have to start from scratch.

Basically I am looking for pointers where to look next, or alternatively
a formum where they discuss such things.

Here is what I've done so far:

csound:

I managed to get a working pitch shifter by using lpanal (lpc-analysis)
and then resynthesize the signal with a programmed excitation signal
whose pitch I can control. The results were promising: formants were
not shifted, there is no chipmunk (aka Mickey Mouse) effect and you
could clearly identifify the singer. The overall quality however was
still too bad, the voice sounded kinda rough. I could get some
improvement by fine-tuning the spectrum of the excitation signal.

My conclusion was that the final step should always be an LPC
resynthesis (to get the formants right) and the tricky part is to get a
proper excitation signal. Ideally I would use the residue of the LPC
analysis and pitch-shift that by some standard method to get the
excitation signal, but alas, csound does not give me access to the
residue.

rubberband:

Rubberband does a fine job on pitch shifting, but it shifts formants
too, so you get the infamous chipmunk effect. There is an
option "preserve formants" but it does not work right.

audacity:

Audacity, like rubberband, does only do naive pitch shifting, with
formants shifted, i.e. you get a chipmunk effect.

clam:

Clam lets you graphically plug together an audio processing network and
it can even produce ladspa plugins (I haven't tried that yet), so it
seems like the ideal tool to me. It does a decent job on pitch-shifting
but it also shifts the formants. There are two LPC analyzers but I
can't see any LPC synthesizers. In fact there don't seem to be any
filters at all (an LPC resynthesizer is basically just a time-varying
digital filter).

praat:

praat does an excellent job on vocal pitch shifting but it is an
integrated tool (though sciptable). It does not work well on large
audio files (it becomes very slow) and there is no hope that pitch
shifting with praat could ever work in realtime.

commercial:

I haven't looked too deeply into commercial tools. I am aware of
- Antares autotune
- Melodyne
- Max/MSP




I use Melodyne and it is not far short of miraculous in what it can do. There may be a trial version.

d
.

Relevant Pages

  • Re: vocal pitch correction toolkits
    ... I've been looking for a free vocal pitch correction software or toolkit ... The results were promising: formants were ... My conclusion was that the final step should always be an LPC ... Rubberband does a fine job on pitch shifting, ...
    (rec.audio.tech)
  • =?ISO-8859-1?Q?Re=3A_Redefining_=5Ba=5D_and_=5B=E6=5D=3F_or_using_a_better_vowel?= =?ISO-
    ... F0 (pitch) between the following two lines in a hymn might have the ... F1 and F2 are resonance frequencies, based on the shape of the mouth ... Of course, there will be minor variations in the formants, because ... (I even have a tape of a singer singing the five vowels at frequencies ...
    (sci.lang)
  • Re: How formants structures affect autocorrelation peaks detection?
    ... Did you see the pitch as regular repeats of the waveform in the ... The major Peak in the autocorrelation function corresponds to pitch ... harmonics in the power spectrum, ... formants are not regularly placed in the spectrum. ...
    (comp.speech.research)
  • Re: why cant the BBC
    ... Moreover, the Hz's of formants are the pitch of any actual tone, but ... at exactly the same pitch and the listener can still reliably tell ... speaker to make contrastive distinction between vowels. ...
    (sci.lang)
  • vocal pitch correction toolkits
    ... I've been looking for a free vocal pitch correction software or toolkit ... The results were promising: formants were ... My conclusion was that the final step should always be an LPC ... Rubberband does a fine job on pitch shifting, ...
    (rec.audio.tech)