This page is read from MIDI Instrument Definitions, a Python library used in the author's other projects, in which every number is traced to a document its maker published. Its source is on GitHub.

Roland JX-8P MIDI implementation

The MIDI implementation of the Roland JX-8P: what it answers to, and the 5 controls it offers.

At a glance

Firmware: Not recorded.
MIDI channel: Any one of 1 to 16.
Voices: 6, or 1 or 3 as set on the instrument.
Note range: 0 to 127: C-1 to G9, counting middle C as C4.
Velocity: Sent and received. Release velocity is ignored.
Aftertouch: Channel pressure, one value for every key. It sends aftertouch too.
Pitch bend: How far it bends is not recorded, and the range can be changed.
Program change: Received and sent, with 128 presets.
MIDI clock: Neither sent nor received.
Start and stop: Neither sent nor received.
Control change: 5 controls, in the table below.
NRPN: None.
System exclusive: Supported.

Controls

In the order the definition gives them, by group. Under each control is the name a program calls it by, once pymidiinstrumentdefs.load("roland/jx_8p") has loaded them.

Control	CC	Values
Modulation `modulation`	1	0-127
Portamento Time `portamento_time`	5	0-127
Volume `volume`	7	0-127 Received, never sent
Hold `hold`	64	0 `off`, 1-127 `on`
Portamento Switch `portamento`	65	0 `off`, 1-127 `on`

Where these facts come from

Source documents

JX-8P Owner's Manual, its user manual, read on 8 October 2026 (the file read).
Roland - Support - Manual Archive, its download page, read on 8 October 2026 (the file read).

How they were read

Owner's Manual, 34 sheets, a scan: the contents at sheet 3, the panel at sheet 4, the features and connections at pp. 5 and 6, the performance controls and key modes at pp. 8 and 9, the patch chain at p. 10, the tone parameters at pp. 14 to 18, the MIDI functions at pp. 24 and 25, the specifications at p. 27, the MIDI implementation on sheets 28 and 29, its chart on sheet 31, and the back cover on sheet 34. And Roland's manual archive page, which links it.

ROLAND LINKS THE MANUAL FROM ITS MANUAL ARCHIVE. The archive lists "JX-8P Owner’s Manual" (archive), on the page roland/jd_800, roland/juno_106 and roland/tr_909 already cite. It also lists a "PG-800 Owner’s Manual" (archive) for the optional programmer, which plugs into its own 6-pin socket rather than into MIDI (manual p. 6) and is not read here. The JX-8P has MIDI In, Out and Thru: "MIDI Connectors × 3" (manual p. 27).

FIVE CONTROLLERS, BEHIND FOUR SWITCHES. The chart marks 1 Modulation, 5 Portamento Time, 64 Hold and 65 Portamento Switch with an asterisk both ways, and 7 Volume with an asterisk as recognised and a cross as transmitted (manual p. 31); its Notes row says an asterisk can be set to yes or no by hand and is memorised. The implementation says what sets it: every controller it sends carries "*1 Transmitted if the corresponding function switch is ON." (manual p. 28) and every one it receives "*3 Received if the corresponding function switch is ON." (manual p. 28). The function table's rows for them are 15 to 18 - MOD,WHEEL, PORTAMENT, HOLD and VOLUME on the display - so if the one portamento row is the corresponding switch, it governs both 5 and 65; the manual never pairs a row with a message. Every one is ON from the factory, as are rows 12 to 14 for program change, aftertouch and pitch bend (manual p. 25).

THE TABLE'S OWN FOOTNOTE SAYS HALF OF WHAT ITS SWITCHES DO. It reads "ON = Sent, OFF = Not Sent" (manual p. 25), where the implementation gates reception by the same switches (manual p. 28), and the table gives a switch to Volume, which the chart crosses as transmitted (manual p. 31) and the transmitted list leaves out (manual p. 28). Read the implementation.

CHANGING THEM: the Edit button's MIDI page, a function number from "the Tone Selector buttons 1 to 9" (manual p. 25), and the Edit Knob for its value. The change is kept only by writing it: "Set the Protect Switch on the JX-8P to OFF." (manual p. 25), then the Write button, which shows WRITTEN MIDI (manual p. 25).

NO PAGE SAYS WHICH CONTROL SENDS WHICH CONTROLLER. The evident sources are the hold pedal, "Connect the damper pedal DP-2 (optional), and the Hold effect can be turned on by pressing the pedal." (manual p. 6), and the portamento switch and knob: "The portamento effect will be on by setting the Portamento Switch to ON." (manual p. 9), and "The time needed for a sound to change from a pitch to the other can be altered by using the Portamento Time Knob" (manual p. 9). For modulation there is none: the panel has no wheel (manual p. 4), its function row is named Modulation Wheel and described as "LFO Switch On/Off" (manual p. 25) while the implementation carries 1 over 0 to 127 (manual p. 28), and the bender lever adds vibrato through the LFO: "Pushing this lever forward will result in vibrato effect." (manual p. 8). Aftertouch can add vibrato too (manual p. 8).

PROGRAM CHANGE REACHES 128 PATCH PROGRAMS, A QUARTER OF THEM ON A CARTRIDGE. The implementation maps 0 to 31 to the internal memory, 32 to 63 to the cartridge, 64 to 95 to Preset #1 and the rest to Preset #2, in both its transmitted and its recognised lists (manual p. 28), and the recognised list adds "When the memory cartridge is not connected, 32 thru 63 are ignored." (manual p. 28). So 96 answer without a cartridge, and 64 of the 128 are the factory's: the specifications give 64 preset, 32 internal and 32 cartridge patch programs (manual p. 27). BOTH LISTS PRINT THE LAST RANGE AS "95 - 127 : Preset #2" (manual p. 28), which overlaps the range above it by one; it must be 96 to 127. The panel names its two preset banks P and -P, each of 32 (manual p. 8), and no page says which is Preset #1, or that a bank's first tone is the first program number of its range.

SIX VOICES, AND THE KEY MODE DIVIDES THEM. The specifications say "6 Voice Synthesizer with Dynamics, After Touch" (manual p. 27). Poly "turns the JX-8P to a 6 voice polyphonic synthesizer" (manual p. 9); in Unison "two sound modules are assigned to each key" (manual p. 9) and "the JX-8P becomes 3 voice synthesizer" (manual p. 9); Solo "turns the JX-8P to a single voice synthesizer" (manual p. 9). Each has a second form, chosen by whether the button's indicator is lit or flashing, and the patch parameters number all six, Poly-1 to Solo-2 (manual p. 29). The key mode is a patch setting: each patch in the Patch Chain can keep a tone with its own "Key Mode, After Touch, Bender Range, Portamento ON/Off, Bend LFO Depth, Unison Detune and Portamento time" (manual p. 10).

NOTES 36 TO 96 ARE SENT AND 0 TO 127 RECEIVED. The keyboard's 61 keys send 36 to 96 (manual pp. 27, 28), and a released key is sent as a note on of velocity 0, where both kinds of note off are received (manual p. 28). The chart recognises 0 to 127 with a true voice of 21 to 108 (manual p. 31), and "Note numbers outside of the range 21 - 108 are transposed to the nearest octave inside this range." (manual p. 28).

VELOCITY IS SENT AND RECEIVED, AND NO SWITCH TURNS IT OFF. Note-on velocity is circled as sent and marked with an asterisk as recognised (manual p. 31), but no function row switches it. Function 23, DYNAMICS, "adjusts the intensity of the Dynamics effect caused by velocity sensitivity. At 99, the effect is its maximum, and no effect at zero." (manual p. 25), at 99 from the factory - though it does not say whether it acts on the keys, on notes received, or both - and each tone has four Dynamics Range settings of its own, for DCO, DCO-2, VCF and VCA (manual pp. 15 to 18). Note-off velocity is crossed both ways.

WHAT AFTERTOUCH DOES IS THE PATCH'S. Channel aftertouch is sent and received; the After Touch buttons choose vibrato, brilliance or volume, and "More than one effect cannot be obtained at a time." (manual p. 8), and the patch parameter AFTER TOUCH SELECT stores the choice (manual p. 29).

SYSTEM EXCLUSIVE CARRIES TONES AND PATCHES, AND IS NOT SENT AS THE INSTRUMENT LEAVES THE FACTORY. Function 26, EXCLUSIVE, is OFF from the factory: "When this Function is turned on, the JX-8P sends the Exclusive Message for connecting itself to a computer and other MIDI devices." (manual p. 25). It sends a whole tone, 59 values - a ten-character name and 49 parameter slots, five of them undefined - when a tone button is pressed, and the parameters that change as they change; a whole patch, nine values, when a patch chain button is pressed, and its parameters as they change (manual pp. 28 and 29). Every message is under Roland's ID and the format type 0010 0001 (manual p. 28). It recognises those and a program number message, which can "Write data to memory with the program #" (manual p. 29) - and no page says whether the Protect Switch stops that. The chart marks exclusive with an asterisk both ways (manual p. 31). This file carries none of the parameter map.

THE MODE MESSAGES AND LOCAL CONTROL ARE THE MIDI SPECIFICATION'S OWN, AND NOT CARRIED. It receives local off and on, all notes off, and omni off, omni on, mono and poly: "Mode Messages (123 - 127) are also recognized as ALL NOTES OFF. MONO ON messages are ignored." (manual p. 28). It sends all notes off, omni off, omni on and poly on, with no footnote to say a switch governs them (manual p. 28). Function 24, LOCAL, disconnects the keyboard from the sound, and function 22, MODE SEND, OFF from the factory, is described as "When this Function is on, even if the receiver is not able to set the mode on its own, the JX-8P can send the mode it selects to the receiver." (manual p. 25). Active sensing is sent and received behind function 25, ACTI SENS, ON from the factory (manual pp. 25 and 28), so as it leaves the factory the JX-8P sends it and listens for it.

TWO MORE FAULTS, IN WHAT THIS FILE DOES NOT CARRY. The implementation's list of tone parameters names both 15 and 22 DCO-1 ENV MOD DEPTH (manual p. 28), where the manual's parameter table has a DCO-1 and a DCO-2 Envelope Depth (manual p. 15) and parameter 22 sits among DCO-2's. And it calls the LFO's third waveform Triangle Wave (manual p. 29), where the parameter table shows SINE (manual p. 18). The first reading of this manual missed the second; the blind second reader found both.

NOT RECORDED, AND WHY:

the firmware and the date, which the manual never states;
the mode, because the chart's default is Mode 1, 3 both ways and memorized (manual p. 31) - a stored setting rather than one default - and while function 21, POLY OMNI, is ON from the factory, its only description is "This sets the JX-8P's mode."

(manual p. 25), which does not say which mode ON is; and a pitch bend range, which is a patch's: "The maximum effect of the bender can be optional with the Bend Range Switch" (manual p. 8), at "Major 2nd, Minor 3rd, Major 3rd, and Perfect 5th." (manual p. 8), with no default stated.

AND ONE DOCUMENT THE MANUAL POINTS TO THAT ROLAND DOES NOT SERVE. The contents page asks the reader to read "the separate volume" (manual p. 3), which it calls MIDI, before the manual, and the accessories include a "MIDI Guide Book" (manual p. 27). The archive lists no such volume, and nothing in the manual says whether it is about the JX-8P or about MIDI in general.