Getting Started with SMS (Spectral Modeling Synthesis)
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Downloading and Installing SMS software
You can download software for SMS for Linux, Windows or Mac OS 9
from the webpage:
You will have to register for a free account the first time you
download the software. Select a version SMS 2.6.3 for your computer.
Alternatively, you can access the SMS frontend on the web
from the webapge:
http://www.iua.upf.es/sms/frontend/
. In this way you will not need to download and install any
software; however, using sms via the web can be slow, especially with
longer soundfiles. Also, the web interface does not seem to be
working right now (13 Jan 2003).
Using the sms program in linux
The sms program has been installed at Peabody on mambo in the
directory /usr/local/sms. To use the sms program,
log into mambo remotely as you usually do. To check if the command
is available, type the following command:
which sms
The which should reply that the sms program is
located in /usr/local/bin/sms.
You can type the command sms by itself to see the basic
help for the program:
# sms
SMS version 2.6.3
usage:
sms analysis FileName
sms synthesis FileName
sms tosdif FileName
sms fromsdif FileName
The sms program can either create a soundfile or analyze an existing
soundfile according to the parameters commands you write in the
score-file which is the second argument given to the sms
command.
Basic help for the sms command can be found by typing the
command
man sms
or clicking on this link: http://www.iua.upf.es/sms/dist/docs/sms.html.
The next two sections demonstrate a basic score-file
for analysis and synthesis of a sound.
SMS analysis
In order to manipulate a sound file with the sms program, you need
to go through two steps:
- Analyze the a soundfile to generate sinwave tracks and noise
models of the residual sound.
- Synthesize a new sound with various transformations such as
changes in pitch, duration, harmonics.
The analysis stage of sms requires a score-file which contains
parameters necessary to analyze a sound. There are many parameters
which are used to control the analysis of the sound. Refer to the online
manual for a complete description of
the score-file. In particular, view the analysis
parameters. An old summary of the analysis
parameters is available on this website which will be converted
eventually to the newer sms score-file syntax.
Sample sounds for use with SMS can be found in the directory
/usr/local/sms/sounds.
As an example, download the file flute-c5-22050.wav
and run the sms program with the following script, flute-c5.anl:
The command to type is:
sms analysis flute-c5.anl
This command will read the soundfile flute-c5-22050.wav
and generate the SMS analysis file flute-c5.sms which
contains spectral anlayses of the soundfile and is usually about 10x
larger than the orginal soundfiles, so don't keep too many of these
files lying around or the server will get full fast. Also note that the
score-file cannot contain tab characters.
The soundfile can be analysed with many different settings for
the options, but the default settings are good for monophonic
harmonic sounds. Next, the file flute-c5.sms can be used
to generate new sounds. As demonstrated in the next section.
SMS synthesis
sms synthesis flute-c5.syn
This will generate a soundfile called
flute-c5-sines.wav which contains only the
major sinewaves present in the original soundfile.
The resulting file sounds pretty similar to the input sound, but
it is different. Listen to the input and output files and see if you
can hear a difference. The following command can be used to
listen to the difference between the two files:
subtract flute-c5-22050.wav flute-c5-sines.wav difference.wav
This command will subtract the second file from the first file sample
by sample, and put the result into the third file.
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