Scale reading uncertainty? please help

[steed of the man]

Hi everyone,

I'm currently using the audacity 1.3 Beta for my advanced higher physics project. I need to know the scale reading uncertainty and calibration uncertainty of the frequency analyser within audacity.

Can anyone help?

[steve]

Which frequency analyser?

[steed of the man]

The way I get to it is:

analyse -> plot spectrum

the algorithm is on spectrum, function is hanning window, size 2048 and axis is on log frequency.

Hope that helps

[steve]

Plot Spectrum uses FFT analysis to measure the frequency content.

The audio data is split into frequency bands and then the "amount" in each band is measured.

The number of bands, hence the frequency resolution, is set by the FFT "size". For a Size of 2048 the full spectrum is divided into 1024 frequency bands, so that's about 20 Hz per band. At the maximum size (16384) there are 8192 frequency bands (number of bands = size/2) so that's a little less than 3 Hz per band. The graphic display is extrapolated from the FFT data. The vertical dB scale is normalized so that a 0 dB sine wave will show as 0 dB on the vertical scale.

You can also access the raw data as a text file by using the Export function.

Hope that helps

[steed of the man]

Thanks, that helps alot