[Lf] Slow Voice experiments]

[Andre' Kesteloot]

"'Geri' Kinzel, DK8KW" wrote:

> Lionel, G3PPT wrote:
>
> > As far as slow audio goes, I wonder if it would be possible to record 2
> kHz
> > bandwidth  speech into a .WAV file at 44100Hz and then alter the sampling
> > frequency in the file header to 11025Hz. Playing this would result in the
> > speech with a duration four times as long but in one quarter the
> bandwidth.
> > The frequency band would span 1 to 500Hz, so this would need to be
> > transposed up to 300-800Hz in order to go through an SSB filter.
> Reception
> > could be by similar techniques to those used in QRSS.EXE referred to
> above
> > but with a further transposition to restore the original pitch. With the
> > SB16 card, it would be possible to play a .WAV file at 5513Hz though a
> 250Hz
> > bandwidth  but not all soundcards allow the choice of non standard
> > frequencies
>
> Lionel,
>
> Cool Edit 2000 (http://www.syntrillium.com/) has a transpose feature, in
> which you can transform the speed and make a recorded message four times
> longer, reducing the bandwidth. You can do the opposite, too.
>
> I tried to push a 100 to 900 Hz (so within the DL 800 Hz bandwidt
> limitation) message created with Cool Edit through my PA/antenna
> configurarion ... sounded terribly awful and distorted! I suppose, the
> antenna bandwidth is too small and the PA not really linear enough ... I
> will do futher experiments.
> Please everyone feeling disturbed please feel free to tell me immediately
> ... I don't want to block the entire band ...
>
> Best 73
>
> Geri, DK8KW (W1KW)