I've been looking around the internet for this. Surprisingly, I can't understand exactly what pitch spelling is. I know what a pitch in the musical sense means, but I can't understand what do we do exactly when we pitch-spell?
Spelling a pitch relates to the system of naming notes by letters (A-G) and sharp(#) and flat (♭) signs - and sometimes double sharp and flat signs, resulting in names or 'spellings' like 'A♭', 'D#', 'F♭♭'.
Translating between frequencies in Hz and such names is non-trivial. You need to consider :
- The 'concert pitch' you are taking as a reference
- The temperament in which the piece is played
- The overall key that the music would be notated in
- Use of the correct enharmonic equivalents for accidentals (Using the correct enharmonic equivalent, Purpose of double-sharps and double-flats?)
If translating between, say, MIDI note numbers and 'spelled' names, the first two steps can be skipped.
Spelled pitch names often have an octave number appended for disambiguation - e.g. 'A♭3', 'D#5'.
Most commonly, "spelling" refers to the identification of an enharmonic equivalent name for a given pitch. For example, if you are writing a piece for a keyboard instrument, and you want the player to play the middle black key from the group of three black keys, do you write it as G♯ or A♭? The answer depends on the context. If the person writing the music makes an unconventional choice, someone might say "this music is difficult to read because of the unexpected pitch spelling."
By extension, the term can be applied to intervals or even entire chords, as in "why did you spell that as a minor third rather than an augmented second" or "that chord progression includes a G7 chord that is really a misspelled augmented sixth chord."
Pitch Spelling is a term used in computers and music. It seems to have developed over a 50-year timeframe. It's applications are varied from music analysis, use in music notation software and I'd assume there's still research going on about it.
It's as much about music perception
(Is it an A-flat or G-sharp? [this seems the most cited enharmonic example])
as it is about using computers to analyse and predict a pitch spelling. There's definitely an artificial inteligence aspect to this as we are talking about predictions and algorithms.
Various researchers / theorists have developed algorithms predicting pitch spelling that has an accuracy of above 97%. The accuracy was measured using a large amount of music mainly comprising of 80% Baroque music and about 3% music of Beethoven, and 27% unspecified music but I got the impression that it was pre- or contemporous Beethoven.
The main people that arise in creation of these algorithms (and research) are: David Meredith, Elaine Chew and Yun-Ching Chen, David Temperly, Emilios Cambouropoulos.
David Meredith's video Microsoft Research Video 135944: Algorithms for discovering repeated patterns and computing pitch names in music is infomative but very involved with maths and I assume the Lisp programming language. Obviously computing pitch names is synonymous with pitch spelling. The main sources of information I found were from Computer Music Journal and that's where the majority of hits with the keyword "pitch spelling" came from.
It seems the music analysed is biased towards music before the Twentieth Century but in the European Classical Tradition.
Edit: David Meredith lecture notes The Perception and Cognition of Pitch Structure in Tonal Music (2003) seem valid for further enquiry.