The Philips SAA1099 sound generator is a 6-voice sound chip used by some 1980s devices.
[1][2][3] It can produce several different waveforms by locking the volume envelope generator to the frequency generator, and also has a noise generator with 3 preset frequencies which can be locked to the frequency generator for greater range.
It can output audio in fully independent stereo.
The following sound cards and computers used the SAA1099: