sqsl Nashville

sqsl Nashville is a MIDI controller/tool for exploring harmonies, modes, and chord progressions within heptatonic scales.
Concept
When we press a key on a traditional MIDI keyboard/piano, we are saying: "play a specific note (pitch/frequency)". When we press a "key" in the Nashville app, we are saying "play a chord shape from this degree of the currently selected scale". The played chord shape is defined as a set of degree offset(s) from the played degree.
Examples
1/ If the scale is set to C Major and the chord shape is set to be 3 notes (1, 3, 5), playing keys 1 to 7 would result in C Major's triads (CEG, DFA, EGB, FAC, GBD, ACE, BDF).
2/ If the scale is set to C Major and the chord shape is set to be a single note (1), playing keys 1 to 7 would simply play the 7 notes of the C Major scale (CDEFGAB).
3/ If the scale is set to C Major and the chord shape is set to be a single note (2), playing keys 1 to 7 would play the notes of the C Major scale but shifted by one degree (DEFGABC).
Setting the scale
Scales in Nashville are set using 3 parameters:
- Scale pattern: semitone distance (interval) pattern
- Mode: rotation of the scale pattern, defining which member of the scale pattern is used as the start point
- Root note: which absolute note (pitch) is used as the start point for the rotated scale pattern
Examples
1/ We select Diatonic as our scale pattern—meaning we want to work with the interval pattern 2-2-1-2-2-2-1 (or whole, whole, half, whole, whole, whole, half). We select the first Mode (I), which means we will not rotate the scale pattern, and we select C as the root note. We have set the scale C-D-E-F-G-A-B—usually called the C Major scale.
2/ We select Diatonic again (2-2-1-2-2-2-1) but now we select the third Mode (III)—the pattern is rotated by two steps, so we get 1-2-2-2-1-2-2. Selecting C as the root will result in this scale: C-C#-D#-F-G-G#-A#. A very different set of pitches from C Major but related, as it originates from the same scale pattern.
Usage (example)
Trigger notes/degrees in the PLAY section, capture them in a loop, and change the pattern/root/mode and chord shape to explore variations. Looped data can evolve—timing/degrees are randomly recombined at the end of each loop.
Using with MIDI keyboard
- White keys always trigger degrees of currently selected scale (chord shapes are ignored)
- Black keys are used to change the scale on the fly
- Press C# and following key will set Root
- Press D# and following black key will set Scale Pattern
- Press D# and following white key will set Mode
- F#, G#, A# keys are used as 3 positions where 3 scales can be stored and recalled (long press = store, short press = recall)
Notes
- Settings and loops are saved automatically but there is no preset system
- App runs in the background
- Only standalone (no AUv3 support)
- Does not produce any sound of its own (only MIDI notes)
- More details at https://www.seqsual.com/nashville