Nintendo Entertainment System

The Nintendo Entertainment System (commonly abbreviated as "NES") is an 8-bit video game console made by Nintendo, which was released in 1985. It is a third-generation game console.

Games
The Nintendo Entertainment System utilized cartridges to play its games.

Sound Specifications
Because video game consoles were a relatively new concept at the time, the sound was not very advanced, and was in fact rather simplistic. Sound cards for processing sound files were not used; instead, the sound in every game was generated by a sound chip in the game cartridge itself. Therefore, the iconic music was created by combining the available waveforms in various ways, and applying effects such as echo, reverb, and pitch-bending.

The NES supported five sound channels; two pulse channels (with four pulse width/duty cycle settings), a triangle wave generator, a noise generator, and a pulse modulation channel that played low-quality digital samples.

Pulse Waves 1 and 2
The sound that these channels output, also known as the "square wave", is responsible for the instantly recognizable "8-bit" sound. It is mainly responsible for providing the higher-pitched sounds. The four pulse width/duty cycle settings are 12.5%, 25%, 50%, and 75%. The higher the number, the "fuller" the sound.

The 25% and 75% duty cycles sound identical.

Triangle Wave
The triangle wave is most commonly used for basslines. It has only one voice (meaning that there are no duty cycle settings), no volume control, and cannot fade in or out. However, its pitch can be altered to create percussive effects.

Noise
The noise channel is used only for percussion and sound effects. It somewhat resembles a television displaying static. Two examples of this are the sound of Mario breaking bricks in Super Mario Bros. for the NES, and the "drums" in the Overworld Theme from the same game.

Sampling Channel
This channel, also known as the DPCM channel, (differential pulse code modulation) is used almost exclusively for either drums and percussion or vocals. Examples of this are the Stage 2 Theme in Silver Surfers, the Bowser Battle theme in Super Mario Bros. 3, and the Title Screen theme in Blades Of Steel. However, certain SunSoft games sample basslines. For the most part, all samples are 1-bit. This is because of the heavy compression required to squeeze such large samples into the NES sound bank. Because samples took up so much space, it was rare to see more than four of them used in one game.