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.

Korg RADIAS MIDI implementation

The MIDI implementation of the Korg RADIAS: what it answers to, and the 176 controls it offers, on firmware 2.0.

At a glance

Firmware

This page describes firmware 2.0.

MIDI channel

Any one of 1 to 16.

Modes

Program: the mode it ships in.
Drum.

Parts

Timbre, 4 of them: each on a MIDI channel of its own, taking notes, controls, and program changes, in Program only.
Vocoder: on a MIDI channel of its own, taking controls, in Program only.
Drum kit: on the base MIDI channel, taking notes and program changes, each note working what is listed for it below, as it leaves the factory, in Drum only.

MIDI mode

3: omni off, poly.

Voices

24, or 1 as set on the instrument, shared by the parts that play notes.

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 256 presets.

MIDI clock

Sent and received.

Start and stop

Received.

Control change

Assigned by the player, apart from the 68 controls below.

NRPN

Supported. 108 of the controls below have one.

System exclusive

Supported.

Drum kit notes

The player assigns this part's notes, and these are the notes it has from the factory.

Controls

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

Timbre

In Program only.

Performance controllers

Modulation sources

UNISON

PITCH

OSC1

OSC2

MIXER

FILTER

FILTER1

FILTER2

AMP

EG1

EG2

LFO1

LFO2

Virtual patch

EQ

Modulation sequencer

I.FX1

I.FX2

On the base MIDI channel

Bank select

M.FX

Arpeggiator

Step sequencer

Program

Vocoder

In Program only.

Vocoder

Where these facts come from

Source documents

• RADIAS MIDI Implementation, Revision 1.0, dated 22 September 2005, its MIDI implementation, read on 11 October 2026 (the file read).
• RADIAS Owner's Manual, E 2, dated 27 December 2005, its user manual, read on 11 October 2026 (the file read).
• RADIAS Function added in system version 2.0, E 1, dated 9 July 2007, its firmware addendum, read on 11 October 2026 (the file read).
• Downloads | RADIAS | KORG (USA), its download page, read on 11 October 2026 (the file read).

How they were read

RADIAS MIDI Implementation, Revision 1.0, 61 pages, dated 2005.09.22 on its second page; the RADIAS Owner's Manual, edition E 2, 176 pages, created 2005-12-27 by its own metadata; and RADIAS Function added in system version 2.0, six pages, created 2007-07-09. Korg's downloads page for the instrument offers all three, no later implementation and no later system: its two rows for "RADIAS/System Updater" (download_page) are both at 2.00, which is where firmware comes from.

THE IMPLEMENTATION IS A TEXT DOCUMENT IN A PDF, AND IT WAS READ AS ONE. It is set in a fixed-width face and its tables are drawn in characters, so a row is one line and its cells are what lies between the bars. Notes/4929_read_radias.py reads the channel tables (implementation pp. 2 and 9), the two NRPN tables (implementation pp. 3-4 and 9-10), the panel table (implementation p. 6) and the notes that say what a value means (implementation pp. 4-7), and asserts every count stated here about those tables.

THE TABLES WERE READ TWICE, BY TWO READERS WHO DID NOT SEE EACH OTHER'S WORK. The first used PyMuPDF. The second used pypdf and PDFium for the text and PDFium for renders of the pages, and transcribed the factory map row by row from enlarged renders, comparing it with the text afterwards. Notes/4929_compare_readings.py compares the two row for row: both channel tables, both NRPN tables, the 57 panel rows, the 70 rows of the factory map with the section each stands under, and sixteen notes of named bands. They agree in every cell.

THE MANUAL ENDS WITH A MIDI IMPLEMENTATION CHART, ON A PAGE THAT PRINTS NO NUMBER. It is the page after p. 168 and the one the contents list as 169, which is how it is cited here, and it is dated Date : 2005. 10. 6. Its yes and no marks are drawings: no text extraction returns a circle or a cross from it. So every mark this file rests on was read twice, by the script, which tells a circle from a cross by the path each is drawn with and places it by where it stands, and by eye from a render of the page. Its numbers and remarks are text. The mode, the note range, the row for the panel controls and controller 4's direction come from it.

THE FACTORY NUMBERS ARE IN THE MANUAL, IN A DRAWN TABLE, AND WERE READ BY POSITION. Two tables stand side by side on manual p. 151, each a Section, a Parameter and an Initial column, with a section cell spanning the rows it covers. Each Initial cell was paired with the parameter on its own line: 57 rows with a number, from CC#03 to CC#116, and 13 vocoder rows reading Off. All 57 numbers are different, and all are inside the two ranges the map allows. A section's label is set at the middle of the rows it covers, and its extent was counted from that. The same page was rendered and read by eye.

THE TWO TABLES ARE THE SAME 57 CONTROLS UNDER SLIGHTLY DIFFERENT NAMES, and they were joined by name. The implementation heads its rows with a panel section and a short name, FILTER1 and KBD Track; the manual writes Filter1 KeyTrack. The implementation has IFX1 and SW; the manual FX1 SW. The labels below are the manual's, because the manual's row is the one that carries the number. Rows 3 to 57 are in the same order in both. Rows 1 and 2 are not, as the comment above the definition says.

WHAT THE IMPLEMENTATION'S PANEL TABLE ADDS IS WHAT EACH VALUE MEANS, AND WHERE THAT IS A SET OF NAMED BANDS THE BANDS ARE CARRIED. Most rows point at a note or print their values in the row. Twelve of the 57 always divide the 128 values among named settings: the two oscillators' waves and modulation types, the filter routing, the second filter's type, the drive switch, LFO1's wave, and four switches printed 00~3F,40~7F:OFF,ON. Those twelve have values below, each band under the name the note prints and starting where the note starts it, the hexadecimal turned to decimal (implementation pp. 6-7). The script reads every band from the page and asserts that each note's bands cover 0 to 127 with no gap.

THE BANDS ARE PRINTED FOR WHAT IS SENT. The notes stand in the half of the implementation headed "1.TRANSMITTED DATA" (implementation p. 2), and the recognised half gives the panel controls one row and no note. That the same bands hold for what is received rests on the manual's sentence in the comment above the definition, that an assigned control change received acts as the control operated.

FIVE ROWS HAVE BANDS OR VALUES OF A KIND AND ARE LEFT CONTINUOUS. LFO2's wave: the implementation gives both LFOs one note, under the names Saw, Squ, Tri and S/H, and the manual says "For LFO2 you can choose from Saw, Squ+, Sin, and S/H." (manual p. 90). The implementation's own table of a timbre's stored parameters gives LFO2 a third list, Saw,Squ(+),Tri,S&H (implementation p. 25), which agrees with neither. Which name belongs to which band is not printed, and a list is not numbered here by the order it is printed in. Filter1's Type Balance: nine bands, four of them a morph between two filter types, which is a continuous control with five named points and not a stepped one. Unison SW, whose values are printed as 0,40 with no word saying which is which. And the two LFOs' frequencies: their note is two tables, 128 frequencies for when the LFO's Tempo Sync is off and seventeen note lengths in bands for when it is on (implementation p. 7), and which applies is a setting of the sound.

Fifteen of the panel table's 57 rows name a vocoder parameter beside the synth one, because the same knob edits the vocoder when the vocoder is being edited. They are thirteen parameters, two of them named on two rows each. A vocoder parameter does not share the knob's number. It is a slot of its own in the map, one of the thirteen reading Off.

THE EFFECTS' FIVE KNOBS ARE REFERRED ELSEWHERE, AND THE ELSEWHERE IS THE BACK OF THE SAME DOCUMENT. Their rows read "refer midi_imp_fx" (implementation p. 6). No file of that name is on Korg's page. A section of the implementation begins on p. 34 under the heading "RADIAS Effect Parameter Structure" (implementation p. 34) and runs to p. 60, listing every effect's parameters, which is by its heading what is meant. The notes to the dump tables point at it under another name again, (See midifx.txt.) (implementation p. 32). What an EDIT knob does depends on the effect a program has chosen, so nothing of it is carried.

THREE OF THE FACTORY NUMBERS ARE ALSO WHAT THE PEDAL OR THE SWITCH SENDS. Controller 7 is Amp Level in the factory map and is what the assignable pedal sends when it is set to Volume; 10 is Panpot and the pedal's Pan; and 82 is Filter2 KeyTrack and what the assignable switch sends as "Multi Purpose Ctrl17(as Foot Sw)" (implementation p. 2). Each is carried once, as the knob's, since the pedal and the switch are set at the factory to neither: "With the factory settings this is set to ExpPedal." (manual p. 119) and "With the factory settings this is set to Damper." (manual p. 119). The chart gives each of the three a row of its own, as Volume, Panpot and Foot Switch, marked yes in both columns (manual p. 169). The implementation's recognised table has no row for any of them, and the manual makes the effect of the first two conditional on the map: an incoming volume message controls the volume if AmpLevel is assigned to controller 7, and pan likewise (manual p. 148).

AN ARRIVING 82 IS TWO THINGS AT ONCE, AND NO PAGE SAYS HOW THEY COMBINE. With the factory map it is Filter2 KeyTrack. It is also, by the chart's row and by the filter each timbre has for it (manual pp. 169 and 79), a foot switch message, and the foot switch is a control source the effects list, F.SW Foot switch (manual p. 126). As with controller 4, no single sentence says that an arriving 82 drives that source. A switch set to FootSw sends only 0 and 127, which as the knob are the two ends of its travel.

108 PARAMETERS ARE REACHED BY NRPN AND BY NO CONTROL CHANGE, and the two NRPN tables agree in their rows but for one. The recognised table has Arpeggio Octaves at 00 03, "Arpeggio Octaves" (implementation p. 9), and the transmitted table has no such row, so that one is recorded as received only. The other 107 are in both under the same names. Each address is two bytes printed in hex and is recorded as MSB x 128 + LSB. "The RADIAS uses only the data entry MSB." (manual p. 149), so a value is one byte and none has a fine half.

EIGHTEEN OF THE NRPNs HAVE BANDS, AND THOSE ARE CARRIED TOO: the arpeggio's type and its selector, the seven modulation sources, and nine switches. The recognised table points at the same notes as the transmitted one, so these bands are printed for both directions. A switch is the exception, and is answered more widely than it is sent: the recognised table prints 00~3F/40~7F:OFF/ON, which is what values records, and the transmitted table prints 00/7F:OFF/ON, so the instrument sends 0 and 127 and nothing between.

WHICH CHANNEL AN NRPN TRAVELS ON IS STATED FOR SOME AND NOT FOR OTHERS. The arpeggiator's and the step sequencers' ten: "These messages are transmitted and received on the global MIDI channel." (manual p. 149). The virtual patches' twelve: "Messages to control the VIRTUAL PATCH 1–6 SOURCE/DESTINATION are transmitted and received on the timbre's MIDI channel." (manual p. 149). The vocoder's filter source follows the vocoder's carrier timbre, and so does what the manual calls CH PARAM (channel parameters) (manual p. 149). That those are the 32 band levels and pans is a reading, which the specifications support: "16-band vocoder, variable level/pan for each channel" (manual p. 168). For the 48 steps of the three modulation sequencers and for the five timbre and vocoder switches no page names a channel. The steps are recorded on the timbre's, because each timbre is a synth program with modulation sequences of its own (manual p. 168) and a number on the global channel could not say whose; the switches are left on the global channel, being settings of the program. Both are readings too.

THE VIRTUAL PATCH VALUES ARE OLDER THAN THE INSTRUMENT'S SYSTEM. The 2005 table divides a patch's destination into fifteen bands, and "RADIAS version 2.0 adds the following parameters as virtual patch modulation destinations." (upgrade p. 2), twenty-five of them. No document says how the value divides now, so the six destinations carry no values, alone among the NRPNs whose note has named bands.

WHAT 2.0 ADDS TO THE CONTROLLERS. It lets the module be played from the keyboard of the M3, and that keyboard's joystick, switches and ribbon arrive as controllers 1 and 2, 80 and 81, and 16 (upgrade pp. 2-4). Controller 1 acts as the modulation wheel does. The other four reach a sound as the Global mode's modulation sources, MIDI1 to MIDI5, which are set at the factory to controllers 16, 2, 80 and 81 and to aftertouch (manual p. 117). 16, 80 and 81 are carried below as factory assignments; 2 is the breath controller's own row in both channel tables and is carried once. 2.0 also adds choices for those five sources: controllers 16, 17, 19, 20 and 21 read about their centre, for the M3's ribbon and four of its sliders (upgrade p. 5). Four of those numbers are panel controls in the factory map below, 17 and 19 to 21, and the note does not remark on it.

FILTERS GATE ALMOST EVERYTHING HERE, AND THEIR FACTORY STATE IS NOT PRINTED. The Global mode has five, for program change, bank change, control change, pitch bend and system exclusive, each for sending and receiving at once: "Specifies whether control change messages will be transmitted and received." (manual p. 118). The control change filter gates the NRPNs and channel pressure too: both carry its letter in the transmitted table (implementation p. 2), and the manual says it of channel pressure in both directions (manual p. 148). Each timbre has filters of its own for what it receives (manual p. 79), the last of them, by its wording, for whatever the others do not name, which is most of the panel map: "Specifies whether other MIDI control change messages not covered by the preceding items will be received by the timbre." (manual p. 79). Whether 82, or the pedal's 7 and 10, fall under the foot pedal and switch filter instead the page does not say. The page that describes the five global filters states no factory setting for any of them, where the pages beside it do for the five modulation sources, the pedal and the switch (manual pp. 117 and 119).

NOT RECORDED, AND WHY. The bend range, a setting of each timbre, BendRange [–12…+12] on manual p. 81, with no factory figure. The thirteen vocoder parameters, which the map leaves without a number. What an arriving panel controller edits in Drum mode, which the manual leaves to inference: see the kit part. The channel messages the implementation recognises beside its controllers, All Sound Off, Reset All Controllers and All Note Off at 120, 121 and 123, and the two Omni messages at 124 and 125 of which the next paragraph says more (implementation p. 9): they are commands and not controls. Until 2026-10-14 control_change was here too, as a map neither learned nor fixed; a table of movable defaults now says learned, beside assignment: default on each of the 57 controls from the table (manual p. 151).

OTHER PLACES THE DOCUMENTS DISAGREE, ON WHICH NO FIELD TURNS. They were met in the reading and are not a search for every one. The implementation's recognised table has rows for controllers 124 and 125, Omni Mode Off and On (implementation p. 9), where the chart marks mode messages with a cross and gives All Notes Off as 123 – 127 (manual p. 169). The two agree if the implementation's rows for 124 and 125 mean what the chart's two rows say together, that those messages silence the notes and leave the mode alone; the implementation does not say so. The implementation numbers the drum kits 01 to 32 (implementation p. 2) where the manual's bank table has Drum Kit 0–31 (manual p. 147). The panel table gives the second filter's KBD Track the note of a value shown as -63 to +63 (implementation p. 6) where the manual gives it [–2.0…+2.0] (manual p. 88). And it gives OSC1's Control1 nothing to do on a drum wave and Control2 nothing on the audio input, where the manual gives each a parameter (manual p. 83).