MIDI Controller Setup Guide

This guide walks you through connecting a MIDI controller to RimuSDR and mapping its knobs and buttons to radio functions.

Lynovation Controllers

RimuSDR MIDI support has been tested with CTR2 devices from Lynovation (https://ctr2.lynovation.com/). The CTR2 is a purpose-built MIDI controller designed with ham radio operators in mind. Lynn at Lynovation has been an absolute pleasure to work with - responsive, knowledgeable, and genuinely invested in making the integration work well. We highly recommend their hardware to any RimuSDR user looking for a polished, reliable MIDI control experience.

Step 1 — Connect Your Controller

Plug your MIDI controller into a free USB port. The operating system will detect it automatically - no additional drivers are normally required.

Step 2 — Open the MIDI Controller Mapping Dialog

Select the menu Settings | MIDI Controller… to open the MIDI mapping dialog. The dialog is titled "MIDI Controller Mapping" and contains:

Profile section

Manage named mapping sets at the top of the dialog — create, rename, and delete profiles here.

MIDI Device selector

Choose which connected MIDI input device RimuSDR listens to.

Mapping table

Shows all current bindings between MIDI controls and RimuSDR functions.

Add row

Select a function from the drop-down and click Add & Learn to create a new binding.

Export / Import Profiles

Save your configuration to a JSON file or restore it from a previous export.

Step 3 — Select or Create a Profile

Profiles let you maintain separate mapping sets — for example, one profile per controller model, or different layouts for different operating modes.

Use an existing profile

Select it from the Profile drop-down at the top of the dialog. The mapping table updates to show that profile's bindings.

Create a new profile

Click New next to the profile drop-down, enter a name (e.g., "CTR2-MIDI Default"), and click OK. The new profile starts empty.

Rename a profile

Click Rename, enter the new name, and click OK.

Delete a profile

Click Delete. Deletion is disabled when only one profile remains — there must always be at least one profile.

Profile notes

Auto-saveProfiles are saved automatically within RimuSDR's settings whenever you make changes — no manual save is required.
BackupUse Export Profiles to save a copy to a JSON file for backup or sharing with other users.

Step 4 — Select Your MIDI Device

In the MIDI Device drop-down, choose your controller from the list of detected MIDI input ports. The device selection is stored as part of the profile.

Device not appearing?

Check power & USBEnsure the controller is powered on and plugged in before opening the dialog.
Linux MIDI toolsRun amidi -l or aconnect -i in a terminal to confirm the OS can see the device.
Re-scanRe-opening the dialog will re-scan for connected MIDI devices.

Step 5 — Map Controller Functions (MIDI Learn)

Each function you want to control requires one binding. A binding links a physical control on your controller — a knob, encoder, or button — to a RimuSDR action.

5.1 — Understanding Action Types

Relative (rel.) actions

Designed for rotary encoders — controls that send a relative increment or decrement value rather than an absolute position. Use these for knobs that spin continuously.

Absolute (abs.) actions

Accept an absolute value (0–127) from a standard potentiometer or slider. The radio parameter is set directly to the scaled value.

Toggle actions

Respond to any button that sends a non-zero Note or CC value.

5.2 — Adding a New Mapping

1. Select a function

In the Add drop-down at the bottom of the mapping table, select the function you want to map. Only unmapped functions are shown.

2. Click Add & Learn

The new row appears in the mapping table with status "Waiting…" — RimuSDR is now listening for a MIDI message.

3. Move the control

Move the knob or press the button on your controller that you want to assign to this function. RimuSDR captures the MIDI message and updates the Bound To column.

Available functions by category

RadioHeadphone Volume (rel.), Speaker Volume (rel.), Mute Headphones, Mute Speakers
TXMOX, Tune, ATU, VOX, RF Power (rel.), RF Power (abs.), Tune Power (rel.)
PCWMic Gain (rel.), Mic Gain (abs.), DAX, PROC, MON, Mon Gain (rel.), Breakin, CW Sidetone, CW Speed (rel.), CW Speed (abs.)
RXMode Cycle, AGC-T (rel.), AF Gain (rel.), AF Gain (abs.), Mute, Squelch (rel.), Squelch (abs.), Toggle Squelch, Noise Blanker (NB), Noise Reduction (NR), Auto Notch Filter (ANF), Filter Preset Next, Filter Preset Prev
PanadapterFrequency Tune, Band Up, Band Down, Next Slice, Previous Slice, Zoom In, Zoom Out, Lock Frequency

5.3 — Re-learning an Existing Binding

1. Find the function

Locate the function row in the mapping table.

2. Click Learn

Click the Learn button on that row. While learning is active the button label changes to Cancel — click it at any time to abort without changing the existing binding.

3. Move the control

Move the desired knob or press the desired button on your controller. The binding updates immediately.

5.4 — Removing a Binding

Click the Delete button on any row to remove that binding. The function becomes available again in the Add drop-down.

Step 6 — Save and Export Your Configuration

Profiles are saved automatically to RimuSDR's settings file whenever you make changes — no manual save is required. Use Export to create a portable backup or share your configuration.

Export a profile file

Click Export Profiles…, choose a file location and name (default: midi_profiles.json), and click Save.

Import a profile file

Click Import Profiles…, select the JSON file. All profiles in the file are loaded and the previously active profile is restored.

Tips

One binding per functionEach function can only be bound to one MIDI control at a time. Assigning a new control to an already-bound function replaces the previous binding.
One control per functionIf a MIDI message is already used by another function, the old binding is removed automatically when you learn it for a new function.
Encoders vs. potentiometersPrefer (rel.) actions for encoders and (abs.) actions for older-style potentiometers. Using the wrong type may result in jumpy or reversed behaviour.
Multiple profilesCreate separate profiles for different controllers or operating styles. Switching profiles via the drop-down takes effect immediately.