Hardware limitations on NES audio
The NES used the Ricoh 2A03 which had numerous limitations. Composers for the console came up with many clever workarounds to get certain sounds.
The Ricoh 2A03 only had 5 sound channels:
- 2 pulse waves
- Triangle wave
- Noise
- Sample channel
For pulse waves:
- They were typically used for melodies
- Monophonic
- They had 4 pulse width available (12.5%, 25%, 50%, 75%)
- 25% and 75% sound the same
- 16 different volume levels
- Supports pitch bend
For triangle waves:
- Typically used for basslines
- Monophonic
- No volume control (either on or off)
- Supports pitch bend
- Can be used for percussive sounds
Noise:
- Used for percussion
- Sounds like TV static
- 16 preset pitches across 2 modes —> 32 unique sounds
- Second mode sounds more “metallic”
- Support frequency sweep
Sample channel:
- Can load in DPCM-encoded samples
- Vast majority of samples are 1-bit
Sources: