This Web based drum machine is based on the Roland TR-909.
This drumcomputer hits the market 1984 and was a long time the state of art in house and techno productions. Shift-Click the Step-buttons for accent triggers. Shift-Click-Move knobs for smoother resolution. Press Save to store a snapshot of the current settings to a flash cookie. Restore snapshot by pressing Load. Clear to delete all patterns and reset all knobs. Drag and drop a pattern button (invisible) to copy a pattern to a new location.
