Underclocking/Overclocking.

While the Gameboy has a decent range, when exploring influences such as dubstep and drum and bass, composers often want to go lower, to get deeper, fuller bass.

While artificial pitch shifting can be achieved easily with computers, it usually results in artifacts and leaves the sound not as good as it could be.
This is where underclocking becomes a good option.

The following video presents one clock changing option, giving the user realtime control over clock speed.


However, the more popular(and easier) option, is to change the crystal oscillator, from 4.194304MHz to 2.097152MHz, although due to the difficulty in finding 2.097152MHz crystals, 2MHz is usually accepted,(the machine stays intune with itself, but is slightly off others)

A guide to this method is available here http://gieskes.nl/underclocking_or_overclocking_the_gameboy_classic_tutorial/

This guide also presents the idea of overclocking, allowing the Gameboy to play at faster speeds and higher pitches.


And here is a song made by Sydney chiptuner Ten Thousand Free Men and Their Families that was written on an underclocked DMG using LSDJ