The ES-4 Gate Expander is a module which works in tandem with the ES-4 or ES-5 to offer 8 on/off outputs for use as gates, triggers, clocks etc. Up to five ES-4 Gate Expanders can be attached to one ES-4 – one per ES-4 channel. (The 8 outputs of the Gate Expander reflect the 8 bits of CV information passed to the ES-4’s DACs.) Therefore you can combine the modules to create a system with up to 40 independent gate outputs – all driven from a single digital connection. The ES-4 Controller software (part of Expert Sleepers Silent Way) also allows the Gate Expander outputs to be used for DIN sync or MIDI output* (note – not just MIDI clock output, but as an actual MIDI port, capable of sending any MIDI messages). Since these outputs are driven from an audio connection (the S/PDIF port), they have sample-accurate timing, which no USB MIDI interface can claim. Note – the MIDI out feature is only officially supported at sample rates of 48kHz and above, though some users report success with specific hardware when running at 44.1kHz. The ESX-8MD mk2 module works for MIDI output at all sample rates.