Re: [Audacity-devel] Quick Question: Frequency and Amplitude

[Rob v.K <cru...@ho...>]

>On 12/1/06, Rob v.K <cru...@ho...> wrote:
> > Just working a bit with audacity for a research project I am doing but 
>am
> > having some trouble finding the functions I am looking for. I would like 
>to
> > have the average amplitude and frequency so I would like to see a 
>function,
> > or part of a function which calculates these values. Now do 
>ComputeSpectrum,
> > FFT, GetProcessedValue (in freqwindow) all calculate the frequency, and 
>what
> > would be the difference between them? Haven't looked into amplify that 
>much
> > as it is the easier of the two, but if someone allready knows what would 
>be
> > good to look at that would be peachy :).
>
>Well, the questions aren't really well formed.  'average amplitude'...
>yes, you could just average the sample values, but it's not a very
>useful measure--- I think you actually want something else (like RMS
>amplitude/power?).  As for average frequency, again, what do you
>really mean?  There's really no such thing (even if you restrict the
>question to discrete transforms only).  Do you mean amplitude/power at
>a given frequency?  Even then, you have to define several other
>parameters (such as window size/function, etc).
>
>Monty

For the research project I am comparing the mean intensity and pitch for a 
large set of spoken sentences. So what I would like is to, for the whole 
sentence to have a value in dB of how loud the sentence was said. Comparing 
this with other sentences by the same person should, in combination with 
other factors, give some kind of indication of emotion (what I'm 
researching). Now I do not have a very good understanding of frequency, but 
in previous research on this subject frequency was seen as very important. I 
have looked through the papers again to see if any give an indication of how 
they measured it, but all I can find is that they have taken the mean 
frequency. Isn't it possible to, using a small window size, look at the 
frequency of that window sample, and then take the average of all those?

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