A semitone above A (440 Hz) will be 466.16376… Hz. Equal temperament means that the exponential increase in frequency is tabulated in log steps like so,
21/12, 22/12, 23/12 .. and so on.
Equal temperament, or some approximation to it, means our music can modulate to a different key.This means nothing to most people let alone a bird. A system based on log 10 sounds more bird-like and is easy to implement with Praat; here is a sample:
; climatehoax.ca@gmail.com
writeInfoLine (“Log10 Bird Sequence 10^ed * 400 + 150”)
pitchTier = do (“Create PitchTier…”, “source”, 0, 0.95)
t0 = 0.0
tinc = 0.1
for i from 1 to 45
ed = randomInteger(1,10)
do (“Add point…”, t0 + 0.05, 10^(ed/10)*400 + 150)
t0 = t0 + tinc
appendInfoLine ( “ed = “, ed)
endfor
t0 = 0.05 ; between 0.1 and 0.2
pulses = To PointProcess
for i from 1 to 45
do (“Remove points between…”, t0-0.02, t0+0.02)
t0 = t0 + tinc
endfor
do (“To Sound (phonation)…”, 44100, 1, 0.05, 0.7, 0.03, 3, 4)
do (“Filter (pass Hann band)…”, 2000, 2500, 300)
do (“Play”)
Ape Town 