Re: normalisation for spectral levels

[Pierre Divenyi <pdivenyi@xxxxxxxxx>]

Christel,

Rather than getting hung up on formant-peak amplitude differences, it would
be more appropriate to look for changes in formant bandwidth and
peak-to-adjacent-trough ratio. Another way would be to see to what extent
the different exemplars diverge from either a generic neutral vowel or from
formants generated by a uniform tube, as suggested by Rene' Carre' (ask him
for reference, carre@tsi.enst.fr).

Pierre Divenyi

At 01:46 PM 9/24/2003 +0100, Christel de Bruijn wrote:
> Dear list,
>
> I apologise if the following question appears to be trivial.  I would be
> very grateful for an answer though.
>
> I would like to compare formant amplitude levels (in dB, measured from a
> spectrum) of a sustained vowel before and after a reading task. However, I
> adjusted the recording level for each vowel, in order to optimise SNR.
>
> Therefore, it does not make sense to compare absolute dB levels.
>
> I was wondering if I could do a simple normalisation for each vowel by
> substracting its RMS value (after converting it to a dB value) from its
> formant level.
>
> Could I then compare the formant levels, or is this too simple?
>
>
> Regards,
>
> Christel de Bruijn
>
> -----
>
> Christel de Bruijn
> Department of Human Communication Sciences
> University of Sheffield, UK