Gabriel Velasco, one of the groupmembers in my Omnichord Facebook group, came with an explanation how to tackle sus chords on a Qchord. This also suits the later models omnichord.
A little lesson in Music theory :-)
" Sus chords are a bit tricky. The QChord does not play Sus chords. I cannot explain the workaround without a bit of music theory so bear with me. I'll try to keep it simple.
A major chord is made up of the first note of the scale, called the tonic, the third note of the scale, called the third (duh), and the fifth note of the scale, called the fifth. If you flat the third, you now have a minor chord - 1 3b 5.
All of the other chords that the QChord can play - 7th, minor 7th, diminished, and augmented - either have a third which gives you a "major sound" or a flatted third which gives you a "minor sound."
A sus chord is different. A sus chord drops the third. It "suspends" the third. You can't tell whether it's major or minor because it's neither. A sus chord will replace the third with either a second or a fourth. I know I just lost some of you, but hang in there a few more seconds.
You can sometimes find a suitable replacement for the sus chord, but the right replacement depends on the melody. If the melody is not using the 2nd, 4th note of the scale at that point in the music, then you can usually just play the major chord. So, if the song asks for an A2 (sometimes written Asus2), or an A4 (sometimes written Asus4 or just Asus), then you can try playing an A. So, that's usually the first thing to try. Just play the major version of the sus chord in the music. If that doesn't sound good, try the minor version of the chord. In this case an Am. Try the major first, then the minor.
If the melody IS using the 2nd or the 4th note of the scale, now things get slightly more tricky. If you just play the major or minor version of the chord, the 3rd in those chords will clash with the melody. So, if you try the major first and it doesn't sound good, then you try the minor and it doesn't sound good either, you have to try something else.
Sus4 is more common than sus2, and if all that's written is "sus", then it's probably a sus4. If the major and minor don't work it's probably because the melody contains a 4 or 2 at that point, so you'll want to try the IV chord of the song first or the II chord of the song next. I know. Some of your eyes are glossing over right now, but just hang in there. I'll give you a rule of thumb below.
Here's the order of chords to try. Let's assume that the song is in the key of C and the song wants you to play a Csus here.
1. Try a C (major). Does it work? Yay! You're done.
2. Try a Cm. Does it work? Yay! You're done.
3. Try the IV chord. In the key of C, the IV chord is an F. If the melody contains an F at this point, the F major chord might work. Does it work? Yes? Yay! You dealt with tricky one.
4. Try the ii chord. In the key of C, the ii chord is a Dm. If the melody contains a D at this point, the Dm chord might work. Does it? Yay!!! You just dealt with a VERY tricky one.
5. If none of those work, try all of the other chords in the key of C.
6. Doesn't work? You're hosed. Scratch the song off of your list of playable songs, and never bother with it again.
Here's a cheat sheat for chords to substitute for a suspended chord in order:
Csus - C, Cm, F, Dm, Em, G, Am, Bdim
C#sus - C#, C#m, F#, D#m, Fm, G#m, A#m, Cdim
Dsus - D, Dm, G, Em, F#m, Am, Bm, C#dim
D#sus - D#, D#m, G#, Fm, Gm, A#m, Cm, Ddim
Esus - E, Em, A, F#m, G#m, Bm, C#m, D#dim
Fsus - F, Fm, A#, Gm, Am, Cm, Dm, Edim
F#sus - F#, F#m, B, G#m, A#m, C#m, D#m, Fdim
Gsus - G, Gm, C, Am, Bm, Dm, Em, F#dim
G#sus - G#, G#m, C#, A#m, Cm, D#m, Fm, Gdim
Asus - A, Am, D, Bm, C#m, Em, F#m, G#dim
A#sus - A#, A#m, D#, Cm, Dm, Fm, Gm, Adim
Bsus - B, Bm, E, C#m, D#m, F#m, G#m, A#dim
It's a bit off topic, but if anyone's looking...The Suzuki Nobara, I would love to get my hands on one... this instrument rarely pops up on the net. It's one of these Suzuki inventions, Suzuki Japan kept hidden from the rest of the world I guess. Here your chance!