Also revealed was a feature which will allow users to use electronic drum kits and beat boxes within the title's previously announced music creation engine. Beat tracks can be composed on percussion synthesizers and plugged directly into the game to compose songs.
The music creation engine's drum machine offers the ability to program loops with samples ranging everywhere from 8-bit to Indian sounds. Drum machine programming and keyboard playing can be performed via the game's guitar, where notes are controlled by fret buttons and the tilt of the controller changes the octave.
Fine editing of created tracks can be performed via GHMix, an in-game sequencer that allows users to edit together songs using created tracks.
They are in. Don't know if it's a DLC or on the disc, but the lawyer for the band posted something about hammering out the details for Tool in GH4.