The Bluetooth transceiver implements standard MIDI over BLE protocol, sometimes called WIDI (for Wireless MIDI). The WIDI app can be downloaded from the Google Play store or Apple App store in order to control settings, but in many cases this is not necessary because the WIDI adaptor will automatically connect to other Bluetooth MIDI devices. The neoface 2 has three MIDI jacks: one optoisolated MIDI input, and two 5v MIDI outputs. There are two switches on neoface 2: one selects the source from either the MIDI input jack or the WIDI receiver (the middle position mutes the WIDI/MIDI input signals while still providing power from the middle MIDI jack), the other switch controls the out/thru MIDI jack. The middle MIDI output jack provides the selected source (either WIDI input or MIDI input), which is also converted to Voltage MIDI and connects to the effects pedal’s control jack input. The out/thru MIDI jack provides either the MIDI out converted from the Voltage MIDI output coming from the processor inside the effects pedal (which copies the received MIDI input and adds some controller messages), or the MIDI signal from the selected source (a bit accurate copy of the MIDI/WIDI input signal without the inherent delay from passing though the processor), or Power Only (the output provides power to any connected device while muting all MIDI message transmission). The MIDI input jack is permanently routed to the WIDI transceiver’s input and these signals are sent out via Bluetooth MIDI.
About effect pedals with Voltage MIDI
Alexander Neo series effect pedals offer many control capabilities including a complete MIDI implementation. The Neo can store 16 patch memories, but only 4 can be accessed by a long hold on the bypass button. One limitation of their MIDI implementation on Alexander Neo pedals (also on some effect pedals from Meris, Disaster Area, Chase Bliss, Empress and others) comes from the small space available for the control jack. Instead of standard MIDI 5-pin DIN jacks, the control input is on a 1/4″ TRS jack. Unlike the standardized MIDI TRS jack (which come in two flavors: Type A and Type B), some effect pedals implement ‘voltage MIDI’ which is easier to implement than standard MIDI, requires fewer expensive components, but this interface is less standardized. Voltage MIDI requires a special adapter like neoface to convert from standard MIDI (opto-isolated current loop signals) to the 3.3 volt unbalanced ‘voltage MIDI’ and from ‘voltage MIDI’ back to standard MIDI. Since Voltage MIDI is a low voltage unbalanced signal, and not opto-isolated, the length of cables carrying the signal are very limited. But in a situation like a pedal board this is not likely to cause any problems as long as the control cables are only a few inches long.
