New App I am working on
My guess is that very few people read this - they are all out on FaceBook .. but anyway, I'm working on a new app very feverishly . (I should be working on old apps, but there are things I want to try out).

Anyway, it's called PolyHarp, and it's kind of a update to my old Amiga program LYR. LYR was an Amiga based autoharp simulator.
It played MIDI synthesizers and had some pretty bizarre chords and features, including a strum sequencer.But LYR never got to a stage where it was user configureable.

The main differences are:
- iPad only .. it's too big for a iPhone.
- synthesized, not MIDI. that means chords can be made of any musical intervals, not just those in a 12EDO scale.
- "strings" on the harp correspond to the strings of the chords.
- of course any chord setup can be transposed.
- you can make up polyharps with a great number of chords
- you can layout the chord buttons all over the screen
- a chord bar is a collection of intervals which themselves are transposed by a relative interval, which is resolved to a base "key"
- strings are resolved within an adjustable frequency range.

Thus, if your Base key (frequency really) is an F, a "IM" chord becomes an "FM", a "V7" chord is "C7". but there are vast numbers of new chords to be made,
like ones with other equal temperaments, or just ratios, equal divisions of other intervals, or merely cents.
You can compare variations on the same chord. The chord bar intervals are specified with the good old tonality spiral used in Droneo.

Audiobus support will help it along!

PolyHarp is an extended chorded zither-like instrument that runs on the iPad.

It's related to LYR which I wrote for the Amiga before you were born.

PolyHarp's new idea is that the chords create the strings, so you can have a chord set based in any key, and have any intervals in any chord based off any interval.
These base frequencies are specified as standard note names like C#4 or as Hertz. All the intervals follow Droneo's interval specification format, so you can say 4/3, 762 (cents), 5:19 (5th degree of 19-TET) and 7:11@3/2 (7th degree of 11 equal divisions of a 3/2). I also added presets for standard intervals like II, VIIb IV# ,Ib, so you can build some standard chord sets. In fact, you build chord bars using that syntax or using a tone spire like Droneo's

PolyHarp can be subtractive (damping) or additive (undamping) . Damping means pushing a chord bar button damps the strings that aren't in the chord. Pushing two bars results in fewer "live" strings. Additive (undamping) system works the other way, the strings are normally all dumped and more are activated by pushing the bars. That way, you build up chords with multiple chords bars. There are also lock bars , which lock themselves as if pressed, and there are hammers which play all the strings when you press it. The felts, by the way, are just manipulating the 'damping" of the string, and so you can have "bad" felts that damp more slowly than "good" felts. You can also have the option of being able to excite damped strings on a strum, so it has that classic 'washboard-y' sound.

PolyHarp has an extremely simple oscillator structure so that it can be polyphonic (about 50 voices at 44.1KHz) It's a sine that get's clipped a little, with an envelope of paired decays. Very simple. There will be some kind of MIDI support - although I'm not sure the microtonal pitches will be supported.

PoyHarp will also have LYR's "strum Sequencer" which lets you build a strumming pattern independent of a chord pattern. PolyHarp attaches to AudioBus.

The layout of buttons and strings is pretty flexible: you can specify the location of the buttons and the size of the string area and they can be moved so they fit your hand better. I hope to get it out in a few weeks - it's already pretty exciting!