4- This requires additional hardware.

5- The Genesis and NES's wavetable channel is pretty hackish, and not
very high quality; nonetheless it works for speech.

6- The SNES and PSX sound chips accept 16 bit samples which have been
ADPCM 4:1 compressed (this is similar to the ACE compression toolset
on the GS, but the data format is NOT the same).

7- The Sega CD has two channels of 44.1khz stereo 16-bit CD audio and
8 8-bit DAC channels in addition to the capabilities of the Genesis.

8- The Intellivision uses the General Instruments AY-3-8192 chip found
on Apple II boards such as the Phasor and Mockingboard. This provides
three tones and one percussive noise at once.

9- The PowerPC AV Macs have no dedicated DSP chip; they use the main
CPU, which can cause application performance degradation (see also
note 1).

10- AV Macs of both CPU types have a 2-channel 16-bit CODEC to
actually reproduce the audio, but the DSP or 60x chip are capable of
conversion.

11- The Gravis UltraSound PnP specs also apply to other AMD
InterWave-chip based boards such as the Reveal WavExtreme 32. 12- The
Saturn's 32 voices can each be set to either waveform playback or FM.
FM is not limited to sine waves as on older chips, however. 13- Like
AV Macs, the N64 uses a DSP to mix as many sound channels as you can
devote processing time to - however, since the same DSP computes the
3D geometry you're pretty limited on how many channels you would
normally want to use.
_________________________________________________________________

What's this I hear about 3D sound?

Since stereo sound has been around since at least the 1940s, people
have been attempting since then to bring the front-to-back plane into
sound, and not just the side-to-side provided by conventional stereo.
One of the more notable attempts was made in the 1960s with the
so-called "quadraphonic" system, which actually had 4 speakers and
used special LPs with 4 distinct channels. Since this is often
impractical, and nobody wanted to go to the trouble of recording 4
channels anyway, the system faded out by the mid-to-late 1970s.

With the advent of affordable DSP power in the early 1990s, and
advanced psychoacoustic research, many new systems started to appear.
Most popular is Dolby Pro Logic, which encodes 4 channels of sound
into the 2 stereo channels commonly found in stereo VHS tapes and
compact discs. This system uses 5 channels - left, center, and right
in front plus left and right rear, which are actually the same sound.
This system doesn't provide very good sound localization because the 2
rear speakers cannot play different material, and neither they nor the
center channel can play full-range sound. Nonetheless, because the
encoding for this system is cheap and easy to do, a wide variety of PC
and Macintosh software now offers it in either licensed or unlicsensed
form.