H-Pi products are compatible with the widest range of MIDI equipment on the market; however, not all devices are compatible. The easiest way to check is to scan for the words MULTITIMBRAL and PITCH BEND in the user manual of any synth or sampler you want to retune with a TBX1 or Tonal Plexus controller. If pitch bend is supported and the device is multitimbral, then you are in business. There are some details to check which will help to confirm compatibility. You will want to check the MIDI Implementation Chart at the back of the owner's manual. The following parameters must be there:

MIDI IMPLEMENTATION CHART
FUNCTIONTRANSMITTEDRECOGNIZEDREMARKS
Channel Default
Channel Changed
(any)
(any)
1-16
(any)
See note below
Pitch Bend(any)OAll Recognized Channels
Control Change*
0, 32
6, 38
100,101

(any)
(any)
(any)

O
O
O

Bank Select MSB, LSB
Data Entry MSB, LSB
RPN MSB,LSB
Aux
LOCAL ON/OFF
(any) (any) * Keyboard Synthesizers only
MODE 1: OMNI ON, POLY          X = No   O = Yes
IF PITCH BEND MESSAGES ARE NOT RECOGNIZED, THE DEVICE WILL NOT BE RETUNED

* Denotes OPTIONAL functionality

Notes about the requirements listed above:

  1. Channel Default / Channel Changed — There are often two numbers here, in which case the first indicates the number of channels recognized by the device, and the second indictaes the possible settings for each of those channels. If the number of recognized channels is greater than one, the device is capable of producing retuned polyphony.
  2. Pitch Bend — H-Pi products send TUNED output using pitch bend messages. If a device does not recognize these messages, it will not be retuned by the H-Pi unit's MIDI OUT (TUNED) port.
  3. Control Change: 0,32 — this functionality is OPTIONAL; a device might not have banks, for example
  4. Control Change: 6,38,100,101 — this functionality is OPTIONAL; these are needed to set the pitch bend range to the highest resolution possible = 1 semitone, but if Pitch Bend RPNs 100 and 101 are not recognized, the device is still compatible but the tuning resolution will be less exact and tuning tables must be altered to produce correct pitches.
  5. Aux LOCAL ON/OFF: — Keyboard synthesizers without LOCAL CONTROL OFF (or equivalent) can be used as controllers for Hπ products, but without LOCAL OFF a keyboard's internal synthesizer will output two pitches for every key pressed. H-Pi products do not send LOCAL ON/OFF messages, so don't be alarmed if you see an X in the LOCAL ON/OFF box of your MIDI Implementation chart or it doesn't even appear on the chart; even if the message is not recognized, you can usually still set it manually. Look for LOCAL CONTROL OFF in the owner's manual.
  6. MODE 1: OMNI ON, POLY — the device must receive MIDI messages simultaneously on multiple channels and play more than one note at a time if you want retuned polyphony. NOTE: ployphony is limited to number of receiving channels; whereas keyboards are assumed to be polyphonic, wind controllers or mono-lead synths will still work as retuned monophonic instruments, so for those instruments, MODE 2: OMNI OFF, POLY or MODE 4: OMNI OFF, MONO will also work. Some devices have a MULTI mode, which usually means it is MULTITIMBRAL which is the best compatibility.