Every sensor, knob and LED
on TERRA's panel, explained.
PLAY zone below (notes, parametric sensors, Pitch Shifter, holds), CONTROL zone above (Triangular Indicator-Controller, function sensors, knobs). Click any control to inspect it.
Every combination on the instrument.
Sensor legend: L Load · S Save · E Engine · G Gyro · TUNE ⑂ pitchfork sensor · HOLD·P/HOLD·N parametric & note holds · PWR power sensor · ECHO FX mode · < > Pitch Shifter sensors · ▲ triangle sensors.
Design a scale, hear it, tune it.
Pick a tuning system — 66 historical and world systems from Leimma by Khyam Allami & Counterpoint, complete with sources, plus equal temperaments and your own designs. Click a sensor to hear its target, then dial it into TERRA: semitone steps on <±, 0.8-cent steps on >±.
Connect TERRA to any input of your interface — after starting, pick that channel here (inputs 3–4 and loopback buses included). Everything else works without the tuner.
Space play / stop · ← → previous / next sensor
Reference tone · note designer
Click a sensor to hear its target as a raw saw wave. Drag the slider to any pitch — quantized to nothing — and the readout shows the nearest note. Store it to the selected sensor to build your own scale.
Guided tuning
TERRA will show
Triangular indicator readout while tuning (hold TUNE ⑂ + sensor). Top LED = ♯. Blinking middle row = microtonal sharp, bottom row = microtonal flat; faster blink = wider interval.
Tuning on the instrument
Tune one sensor
TUNE ⑂+1–12then<±>±
<+/− steps ±1 semitone (resets microtuning). >+/− steps ±0.8 cents. Hold for continuous. You can also hold TUNE ⑂ + sensor and press a key on a MIDI keyboard connected to MIDI IN.
Transpose / initialize
Whole keyboard: TUNE ⑂+HOLD·Pthen<± octaves, >± semitones (microtuning preserved).
Initialize to chromatic (sensor 1 = C): hold all four < >, add TUNE ⑂+HOLD·P, release those two, release < >.
Just intonation
TUNE ⑂+tonic sensor+
…press top + bottom-left + bottom-right on the triangle. TERRA re-tunes the keyboard to natural ratios from your tonic (double blink = done). The tonic's microtuning resets to zero.
Sixteen intervals under one thumb.
Hold a combination of the four Pitch Shifter sensors before pressing a note to transpose it — each of the 16 combinations (including "nothing pressed") carries its own tunable interval, up to −36/+47 semitones. Explore the factory presets below; click a combination to inspect it.
Selecting a preset
Hold TUNE ⑂+HOLD·P — the triangle shows bank (top three sensors) and number (bottom three, binary). 3 banks × 8 presets = 24 slots.
Tuning a preset (by ear)
- 1Select the preset (above), then press S+TUNE ⑂+HOLD·P+HOLD·N simultaneously — deliberately awkward so you can't enter it mid-concert.
- 2A constant C drones (volume on SUN ☼); a brighter second note tracks the combination you hold on < >.
- 3Hold the combination to tune ("nothing pressed" is tunable too — factory keeps it at 0, be careful).
- 4Semitones: 1–12 (1 = unison … 12 = +11). Octaves: L = −1, G = +1. Microtonal: S = −0.8¢, E = +0.8¢. Just intonation convert: triangle top + bottom-left + bottom-right.
- 5Save & exit: TUNE ⑂+HOLD·P · Discard: HOLD·P+HOLD·N
FW 1.7 — Pitch Shifter hold. Dial a combination and press HOLD·N — it stays latched (LED lit), freeing your thumb. Clear with HOLD·N again while nothing is pressed on < > or the keyboard.
Down-intervals smaller than an octave = −1 octave + semitones up (a semitone down = −1 oct + 11 st). Max shift −36/+47 st.
32 algorithms. Four families.
Each a complete instrument.
Hold E and dial the combination on the triangle: middle row picks the group, bottom row counts the algorithm in binary, the top sensor halves the whole DSP clock to 22 kHz — everything twice lower, slower, bigger, bassier. Names below are our nicknames; SOMA leaves them unnamed.
The interface as a controller.
TERRA transmits — it can't be played over MIDI (its synthesis control is a continuous high-resolution stream that note on/off would strangle). It keeps synthesizing while sending. Enter MIDI Control mode with L+TUNE ⑂+HOLD·P; mode is set on the triangle's top + middle-right sensors, and resets to Off at power-up (MIDI costs 1–2 ms of sensor latency).
"OmniChord" mode
While in MIDI Control mode (L+TUNE ⑂+HOLD·P) press ECHO to toggle. TERRA then receives notes on its MIDI channel and assigns them to sensors 1–n (as many keys as you hold) — a harp that re-tunes itself to the harmony of your sequencer. Stroke across the sensors and you’re always in tune.
Incoming notes don’t affect ringing voices until retriggered — except arpeggiator solos and rhythmic-LFO basses, so you can HOLD the keyboard and re-pitch a running arp or LFO live. Off at power-up.
Manage TERRA via MIDI SysEx
Frame: F0 7E 54 45 52 ("TER") · cmd · bank · preset · cmd · data… · F7. Data = a SOMA .smp file packed 5 bytes per 4 (MSBs zeroed). Banks 0x0–0x5 (0x7F = full dump), presets 0x0–0xF (A–D = 0x0–0x3, 1–12 = 0x4–0xF, 0x7F = live preset).
| Cmd | Action | Cmd | Action |
|---|---|---|---|
| 00/01 | read / write full dump | 06/07 | read / write single preset |
| 02/03 | read / write all pitch shifters | 08/09 | read / write preset sound data |
| 04/05 | read / write one pitch shifter | 0A/0B | read / write preset scale data |
Replies mirror the frame with an acknowledgement byte (00 success / 01 fail) before the data.
CC assignments
| Sensor | CC | Sensor | CC |
|---|---|---|---|
| A | CC16 | 1–4 | CC20–23 |
| B | CC17 | 5–8 | CC24–27 |
| C | CC18 | 9–12 | CC28–31 |
| D | CC19 | Gyro X | Pitch Bend |
Knobs (all modes)
| REL·P | CC102 | SEA ≈ | CC104 |
| REL·N | CC103 | SUN ☼ | CC105 |
| TIME | CC106 | MIX | CC107 |
MIDI channel calculator
Channel = sum of lit sensors + 1, set while holding L+TUNE ⑂+HOLD·P. Stored across power cycles (wait 5 s before switching off).
Clock sync
LFO/arpeggiator tempo: ① fine-tune with SEA ≈ · ② tap tempo — hold D, tap TUNE ⑂ (freezes SEA; rotate ≥10% to unfreeze) · ③ external MIDI clock (SEA becomes clock divider) · ④ CV clock on the MIDI-in mini-jack adapter. Triangle bottom row multiplies tempo ×1, ×3/2, ×2 in the rhythmic algorithms. LFO & arp restart on your next touch of a silent keyboard.
System operations
Master tune
Hold TUNE ⑂, tap E, then use the outer < > sensors. Range ±1 semitone; top triangle LED = A440 (touch it to reset). Persists after 5 s.
USB backup
FAT32 sticks, 1–32 GB. Single preset: S/L + bank + sensor, confirm HOLD·P → TER_B*P**.smp. Everything (96 + 24 PS): S/L + G, confirm HOLD·P → TERRA___.smp. Power-cycle after transfer.
Firmware & calibration
Firmware on the stick root, then L+E, confirm HOLD·P — circular LEDs = success. Calibration (only if your hands are unusually small/large): S+L+E+ECHO, press each sensor's top with your pinky at desired 100%-velocity force, save TUNE ⑂+HOLD·P. Stay grounded, touch nothing else.