| T. Kamiya asked:
>I'm seeking a freeware/shareware spectrum analysis tool (like Spectro3.0
>by Perry R. Cook on the NeXT) for use in the Macintosh environment.
>If anyone knows of such a tool I'd very much appreciate hearing about it.
Here are excerpts from the readme files of several spectral apps for the
Mac. I'm sorry I don't have the ftp addresses handy where you can get them,
but as I recall, they are available at several computer music sites and
should show up on a web search:
-----------------------------------------
AnnaLies is a program for the spectral analysis of Sound Designer II files.
The analysis procedure used is that of the Short Time Fourier Transform
(STFT), implemented as using a radix two Fast Fourier Transform algorithm.
The program takes a sampled time domain signal and and converts it to a
discrete frequency domain representation. The original version of this
program, AnnaLies1.0, was written jointly by David Hirst and Thomas
Stainsby in 1991, and was based on research carried out as part of David's
Master's thesis [Hirst 1985].
Operation of the AnnaLies program follows in the intuitive manner to which
Macintosh users have become accustomed. The overall analysis procedure
essentially takes a Sound Designer II stereo sound file, performs an STFT
analysis of it and stores the result in an FFT (Fast Fourier Transform)
file, which can then be called up and have its data displayed in either a
2D or 3D format.
-----------------------------------------
SoundView
Steve Bird
SBird@SwRI.edu
May 24, 1995
Version 1.3.0 Updated Dec 6,1995
What's all this, then?
This FREEWARE package allows the user to view the time-wave and frequency
spectrum LIVE from any Macintosh® sound input device. Real-time display is
possible on faster Macintoshes; display rates of >110 frames per second
are possible on a Power Mac 8100/100; >35 fps on a Quadra 950. A
"Waterfall", or raster plot of previous spectral history, is presented in a
separate window. Recording and playback of monophonic 8-bit or 16-bit sound
is supported; a spectrogram can be made of the captured data; whether
recorded by SoundView, or imported from a sound file. A readout provides
the frequency value of a point specified by the mouse cursor.
-------------------------------------------------------
//SpectralAssistant.c - an example of how to read and write spectral data files.
// 1996 Tom Erbe - please do anything you want with this code.
-------------------------------------------------------
Spectrum reads and writes Sound Designer II and AIFF sound files. You can
use Spectrum to analyse a sound file and display its series of short time
spectra. You can change the parameters of the analysis and the analysed
data can be saved to a file. Displaying the spectra should be easy to
figure out. There are a few unobvious things:
- the arrow keys expand and shrink the vertical and horizontal display
- command right and left arrow advance and retreat throught the spectra
- clicking on a line in the spectrum pane displays its amplitude and frequency
- clicking on a sample in the waveform pane shows its sample number and
timepoint
You can make modifications to the spectra and resynthesise a new sound
file. Some of the modifications are built in to the application, but there
is a way you can program your own modifications if you own THINK C and the
full version of Spectrum.
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^ Bill Alves email: alves@hmc.edu ^
^ Harvey Mudd College URL: http://www2.hmc.edu/~alves/ ^
^ 301 E. Twelfth St. (909)607-4170 (office) ^
^ Claremont CA 91711 USA (909)607-7600 (fax) ^
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