[music-dsp] Frequency domain never ceases to amaze me...

[=?X-UNKNOWN?Q?T=F3th_L=E1szl=F3?=]

On Mon, 3 Mar 2003, Angus F. Hewlett wrote:

> Because in this case the lowpass filter is smoothing between FFT bins on
> the time axis, so effectively each FFT contains an "echo" of the previous
> one with the delay time being equal to the frame rate.
>
Nope, it contains the "echo" of the previous one AVERAGED with the current
one. Otherwise it is not lowpass. Comb filters and lowpass filters have
quite different frequency response.

> A comb filter clearly has pitch

Only sounds can have pitch, as pitch is something we perceive.
A filter is something that takes an input and returns an output.

> or frequency (it's a filter, after all),
>
Only sine waves can have frequency. Not filters. Filters have frequency
response.

               Laszlo Toth
        Hungarian Academy of Sciences         *
  Research Group on Artificial Intelligence   *   "Failure only begins
     e-mail: tothl at inf.u-szeged.hu            *    when you stop trying"
     http://www.inf.u-szeged.hu/~tothl        *