THE SCREEN

PolyHarp's screen has the following anatomy:

• A Play Area. Touches and swipes here control the actual instrument.

• A Control Area. Here you load and adjust parameters that specify how the Play Area produces musical information.
  

PLAY AREA

The Play Area has two major kinds of objects on it: String Areas and Chord Buttons.

STRING AREA

Strumming here is like strumming strings. Strings which are playable (undamped) are wider at the "bridge" end, those that are damped are thin. The speed with which a string is strummed is passed on to the string synthesis algorithm, so it can be brighter when strummed faster. It's also passed on as a MIDI velocity if you are using the MIDI option.

The distance from the bridge along the string is another parameter that currently is often mapped to intensity and left-right pan for the internal synthesizer. These modulations can be changed.

A string area can have its orientation changed. In fact, it doesn't even have to be a rectangle: it can be any four sided figure, which I call a "quad".

There are other features of string areas, and a PolyHarp can actually have multiple string areas so they can have different ranges and MIDI features. These string areas can overlap or be flipped around.

There is a PolyHarp setting ("Scrub") that also lets the damped strings play, but with much more damping, rather like a real chorded zither.

CHORD BUTTONS

On a real chorded zither, the chord buttons are attached to Chord Bars, which create chords by using little felt dampers to silence the strings which aren't part of that bar's chord. When you strum the strings, only the undampened strings can make a sound. The same principle applies to PolyHarp: the button (and therefore, the bar) creates a potential chord that you realize when you strum the strings. However, there are subtleties!

• The PolyHarp patch may be set so that a chord bar either determines which strings are damped or which strings are to be un-damped. That means pressing several chordbars will allow more strings into the chord instead of removing them!
• A chord button may be a "Lock Bar" which when pressed stays down all the time. This is helpful for constraining the notes to a particular scale, say a diatonic scale, if several scales are are possible on the harp.
• A chord button may be a "Hammer" which plays all the strings it specifies. This makes it like a percussion instrument, or like hitting the strings with your palm.
• A chord button may be a "Relative" button, which transposes all the strings by that interval! That's a bit peculiar, but can make a lot of chords out of just a few buttons.
• There is a setting so that touching a button either keeps holding the virtual chord bar down, which makes life easier on a virtual device like the iPad, or requires you to keep holding the button, just like a real chorded zither.
• There is another setting that lets a quadruple tap on a button turn it into a lock bar.