Re: Pitch Shifting Algorithm

[Pierre Divenyi <pdivenyi@xxxxxxxxx>]

Ben,

"Pitch" refers to fundamental frequency, most of the time. I
think what you want is a spectral up-shift which is actually easier than
the former. There are spectral transposition algorithms that will
displace the spectrum downward -- a simple Fourier transform with
frequency shift will work. Some algorithms of this sort are put in
special hearing aids for persons who have lost their hearing in the
2-4-kHz region indispensable for speech intelligibility. There is no
reason the same algorithms could not be used to shift the spectrum
upwards.

Pierre

At 05:33 PM 6/25/2006, you wrote:
> Hi All,
> I've had a request from someone in our department for suggestions for a
> pitch shifting algorithm that will be used to shift the frequencies of
> phoneme pairs (e.g. ba-da) into the center range of rat hearing (~8kHz)
> without affecting the temporal cues of the speech stimuli. I'm unfamiliar
> with available software to do this (and pros and cons for specific
> kinds). We do have some commercial software here such as Adobe Audition
> and SoundForge that have pitch shifting algorithms as part of their
> software package. We are hoping to limit artifact as much as possible.
> Would these be appropriate algorithms to use? If not, why not and any
> suggestions as to which software program would be more appropriate?
>  
> Thanks,
>  
> Ben Hornsby