I get often asked about simple things like MIDI note/frequency conversion, (for
example what frequency in equal-tempered tuning a certain MIDI number has) so I
thought I  could as well  post some source code about this. This stuff also releveant if
you want to tune an oscillator of your self-made VSTi synth according to the MIDI
notes.

Therefore I have written a fully MPEG4-SA (Structured Audio) compliant Delphi class
of pitch converters! The four representations for pitch in MPEG4-SA are:

- MIDI pitch number representation. A pitch is represented as an integer number of
semitones above or below middle C, representedas 60. For example, 57 is the A below
middle C.

- frequency, or cps representation. A pitch is represented as some number of cycles
per second. For example, 220 Hz is the A below middle C.

- pitch-class, or pch representation. A pitch is represented as an integer part, which
represents the octave number, where 8 shall be the octave containing middle C (C4);
plus a fractional part, which represents the pitch-class. For example, 7.09 is the A
below middle C.

- octave-fraction, or oct representation. A pitch is represented as an integer part,
which represents the octave number, where 8 shall be the octave containing middle
C (C4); plus a fractional part, which represents a fraction of an octave, where each
step of 1/12 represents a semitone. For example, 7.75 is the A below middle C, in
equal-tempered tuning.

I also added routines for converting from/to note strings (like "C#2"), see example
code for usage. 



As if that weren't enough, I also wrote a class that allows adding of microtuning
ability to any of your Delphi projects! This class can easily load/import the widely
spread Scala, VAZ and Anamark formats for scales and tunings!

Considering that the Scala archive contains currently more than 3000 scales from
all over the world, this is definitely a reason to include microtuning in your projects,
it is a useful feature that more and more people want and you now have the
chance to get it all for free and in one easy package!
 

Download pitch class (freeware and open source, including PitchConverter)

Download tuning class (freeware and open source, including ScalaConverter and
several thousand example tunings)

If you use this in any project, no matter if commercial or freeware, please give proper
credits and tell me about it!