Technical Issues
The SineWave Synthesizer
The SineWave Synthesis program (SWS) is a software sound synthesis
system that was developed by Philip Rubin, in the mid-1970s, at Haskins Laboratories.
The synthesizer was intended to be used to create replicas of
natural utterances by replacing the normal formant structure with time-varying
pure tones (sinewaves). The synthesizer is implemented entirely in software
(FORTRAN). The original version was created on a Digital PDP-11/45
minicomputer. More recent versions have been created for the VAX series of
computers running VMS.
Where the sounds came from
The sounds included here were extracted from the original HyperCard stack. The original method used to make the sounds and get them into HyperSWS was as follows:
- Formant center frequency and amplitude values were derived from natural utterances using both the ILS system
(for LPC analysis) and the HADES program (for both LPC and FFT analyses).
- These formant and amplitude values were converted into input (.SWI) parameters for SWS.
- SWS was used to generate an audio file in Haskins (.PCM) format on the VAX.
- Haskins PCM files were transferred from the VAX to the Macintosh in binary
format using the Pacer communications program.
- A Haskins-written Macintosh program called RESAMPLER was used to convert
the Haskins PCM files into Sound Designer II (SD2) format without changing the
sampling rate.
- A commercial Macintosh program called Sound Designer II was used to
"resample" the files (convert the sampling rate) from 10000 Hz (the Haskins PCM
rate) to 11128 Hz (a Mac-compatible sampling rate).
- A commerical Macintosh speech manipulation/analysis program called Signalyze was used to open these files, edit them if necessary, add a DC
offset of 128, and then save them in SoundEdit format.
- A commercial program called SoundEdit Pro was then used to low-pass
filter and amplify the files, if necessary, and save them in the HyperSWS stack as resources.
- For this WWW page, SoundEdit Pro was used again to open HyperSWS, extract the sound resources, and convert them into AIFF format.
Information
