When placed in a position where a harpist is either unaffordable or logistically impossible, music directors must decide whether to hire a keyboard player to adapt the part, or cut it.  When the latter is not an option, such as in Adam Guettel’s Light in the Piazza, the keyboardist (or MD) is left with the beastly task of converting music written idiomatically for the harp into something performable on a keyboard.  The difficulty and style of the music, along with the specific needs of the show will usually determine the means of adaptation.  In this case, the solution hinges on being able to replicate glissandi without interfering with the ability to play other (more pianistic) passages.

To understand the struggle with glissandi, (why you can’t just use a “white key” glissando on the keyboard), you have to understand how a standard concert harp functions.  It contains 7 strings per octave, tuned to a diatonic scale (a concert harp is in C). To alter the tuning, there is a pedal to adjust each diatonic string (in all octaves) to one of three positions: “sharp”, “flat”, or “natural”.  When a harp is tuned to different scales or chords, the glissandi may appear the same on paper, but they will sound extremely different.  To gliss on the white keys of a keyboard while everyone else plays an Eb7 b9 chord would likely raise a few eyebrows.

While there are a few plugins available, the goal here is to use the built-in functionality of Mainstage.  Fortunately for us, there is a way that imitates the pedal functionality of the harp, if we are willing to get our hands a bit dirty.

Rather than pre-recording different gliss patterns into a sequencer or sampler, we can perfectly recreate harp tuning using the “Tuning” tab, under “Patch Settings”.

When you select “User Tuning” as your option, you can adjust each of the 12 notes of the chromatic scale up or down by up to 99.9 cents.  Tuning 100 cents up or down would result in a semitone.  Theoretically, 99.9 is not perfect, but even a highly trained human ear can only reliably hear a difference of 1-2 cents. This should be good enough for our purposes.  That said, it would be nice if Apple developers would lift the cap and allow perfect semi-tone tuning in either direction.


Here is how the tweak works:

  1. Create a harp patch:Harp Patch
  2. Read the pedal notation indicated in the musicHarp notation
  3. Adjust the corresponding white keys sharp or flat as instructed (+ / – 99.9 cents).tuned
  4. As you follow along in the music, mark where changes are appropriate.  Whenever the key changes, or after a set of glissandi, you will want to insert a “concert” patch to be able to quickly return to C tuning.  However, the clever part of this solution is that you don’t have to reset after every gliss.  For instance, if you have a glissando tuned in D major, and for the rest of the number you remain in that key and never have to play an F or C natural, there is no change necessary (i.e. your regular F# and C# will work as normal).
  5. Once you find the tunings that occur commonly, you can simply cut and paste those patches in the order that they need to be.

It helps to first comb the music for different chords and scales that occur: once you create a palette of all of the pedal combinations which produce the major scales, dominant chords, augmented, altered dominant, pentatonic, and other patterns you find in various keys, it is then simply a matter of copying and pasting the patches with the proper turnings into the proper places.  Also, check your music for quick changes, and check the “silence all previous patches” button any time you might have to change while your sound is still decaying.

This took some care and planning, but it was far less work than any other method I’ve read about. It is also much easier to explain to a sub who might be sight-reading the book: as long as you are on the right patch, play what you see and gliss away.