Alesis D4

The Alesis D4 is a classic 1U rackmount 16-bit digital drum and percussion sound module released in 1991. Renowned for its punchy acoustic and electronic drum samples, it functions strictly as a dedicated sample playback "brain" without an internal sequencer.

Key Features and Specifications

• Sound Library: Features 500 high-quality percussion sounds sampled at 48kHz and stored on internal ROM. This includes 99 bass drums, 99 snares, 55 cymbals, 92 toms, 76 percussion instruments, and 80 special sound effects. [1, 2]
• Onboard Memory: Includes 21 programmable drum kits. Each drum set assigns 60 samples across consecutive MIDI note numbers. [1]
• Hardware Controls: Simple front panel equipped with a 32-character, two-line backlit LCD, an alpha-wheel data entry knob, a preview button, and 8 function buttons (Voice, Tune, Mix, Output, Drum Set, Ext Trigger, Group, MIDI). [1]
• Polyphony: Supports 16-voice polyphony. [1]
• Editing Capabilities: Offers basic editing parameters per sample, restricted to adjusting the tuning, panning, volume, and group assignment (e.g., creating choke groups where a closed hi-hat cuts off an open hi-hat sound). [1]

Inputs and Outputs

• Trigger Inputs: Equipped with 12 analog trigger inputs (1/4" jacks). This allows you to directly trigger internal sounds from acoustic drum triggers, piezo pickups, or external sound sources from tape and other studio gear.
• Audio Outputs: Features 4 independent analog outputs (1/4" jacks), which can be configured as 4 mono outputs or 2 stereo pairs for flexible routing and processing of separate tracks (like isolation of kick and snare).
• MIDI Connectivity: Includes MIDI In and MIDI Out/Thru ports with full 16-channel implementation and support for SysEx data dumping to store or load settings. [1]
• Footswitch: One dual-function footswitch jack specifically optimized for a hi-hat pedal to switch between open and closed hi-hat behavior