We continued going over the slides of the Compute Audition Tutorial
and CATbox and talked about the following topics:
1. Difference between Narrow Band and Wide Band spectrograms and mentioned the Bell Labs 1939 VODER as an example of a Wide Band model with synthetic voice input.
2. Mentioned the difference between perfect reconstruction with ISTFT
and Least Square Error reconstruction with ISTFTW2 in STFT folder.
3. Mentioned briefly constant Q transform. Code can be found in ConstQ folder.
4. introduced the notion of instantaneous frequency and spoke about
the hop one trick. Code is in InstFreq folder.
5. Spoke about phase-less reconstruction and spectral-magnitude to
sound conversion. We showed 1940 Haskin's lab pattern playback and
played with Pollock picture. Code is in LSEE folder.
Reference to the theory of LSEE and phase-less reconstruction is the
Griffin and Lim paper, to be found in the CATbox/Publish/Reader
folder.
We mentioned several possible projects related to this material:
1 - Any project that ports something to Octave - may be miditoolbox...
2 - In case anyone would like to learn the theory of LSEE and better
ways of initializing phase. There are some more recent papers on that
also.
3 - Working out a meaningful way of converting images into sound (the
Pollock example).
An additional project that I did not mention in class but that could
be interesting is writing an additive resynthesis program that uses
amplitude and instantaneous frequency from instf as parameters.
In terms of Matlab skills, we mentioned the following commands:
a*b as a vector or matrix product. Requires taking care of row -
column dimensions.
a.*b as a component-wise multiplication.
gave an example of for loop
For our next class I will try to go over LPC and YASA. Those
interested should take a look at the icmc06 paper in the YASA v1.0
folder.
A copy of this email should be logged on http://musicinmatlab.blogspot.com
Please keep the address for future postings.
Shlomo
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