10-04-2017, 03:12 AM
(10-04-2017, 12:19 AM)Nayrb Wrote: [ -> ]Thanks for that Sam! Very good stuff. I'm still somewhat confused, though. I love to write melodic parts for the harp, but I'm often worried I'm overstepping the bounds of the instrument since I'm pretty ignorant of how it works in reality. Is it correct to assume these limitations are still something to consider when writing melodies and parts that require less speed / are not playing chords?
Honestly my best advice is- find a real harpist and ask them on a case-by-case basis. Different harpists can do different feats. Some specialize in fast pedaling and playing highly complex works. Obviously, if you want to make things comfortable for the musician, don't ask for a bajillion pedal changes and instead be economical in when and how much you have to pedal- a few enharmonic swaps in a line can take it from impossible to simple.
For the technical answer- it depends.
What I do is scan and modify my parts so that the enharmonics and everything is correct (remember, I typically work in notation, so seeing if you have both an Eb and an E in a line requires almost zero effort). These limitations apply always UNTIL it is a "correct" time to change the pedals. Obviously a harpist can technically charge the pedals whenever they want, even while the very note they are adjusting is playing (this is in fact a technique used in some special cases). However, the sound of this is typically less than desirable, especially when writing exposed. For this reason, it's best to think about the harp as "set it and forget it" until you reach a new rest period long enough to make any changes necessary- even resting (or simply greatly reducing content) for half a measure can suffice to swap a pedal or two.
This of course is all much harder to realize in a piano roll where the enharmonics are displayed indistinguishable- what happens when you have a C# vs. a Db may be two entirely different strings and sounds on the harp, but will sound as the same on your piano (and virtually all sample libraries of harp as a result). MIDI simply isn't designed to take enharmonics into proper account with MIDI note data and as a result, without convoluted over-engineering of the instrument's controls.
If it greatly concerns you, some DAWs offer "auto transpose" functions that will automatically adjust the input (e.g. C major/"just the white keys") to fit a certain other scale. You could use this to get a true 7-string-per-octave feel on the instrument. Some virtual harps also let you manually set pedals (e.g. Spitfire harp) if this all worries you too much, but harp pedal changes get complicated fast.
But... at the end of the day we just hit a point of "does it sound good?" and "does it sound right?" If you can answer both of those yes, then sleep tight and don't bother making sure everything is right... until you plan on asking a harpist to play your piece. But- that is what so many harpists are great at doing, helping the composer learn to work with the instrument, not fight against its constraints. Harps have remained semantically unchanged since the first decades of the 1800's, a fact very few instruments can claim (aside from bowed strings obviously). Yes, it is an old and perhaps tricky system, but understanding it well can create great effects.