Studio Harmonica

10-hole Richter diatonic · Blow/draw PeriodicWave · Bending · Wah · Adjacent hole coupling

Instrument Summary

A 10-hole diatonic harmonica in standard Richter tuning, playable in 12 keys. Separate blow and draw reed waveforms model the acoustically different blow (exhale) and draw (inhale) reed spectra. Pitch bending on draw reeds is applied as real-time oscillator frequency modulation — real harmonicists bend draw reeds by constricting the throat. Adjacent hole coupling adds the characteristic "chordal bleed" of real harmonicas.

Synthesis Features

Richter tuning: 10 holes × blow/draw = 20 notes covering 3+ octaves with bends
Separate PeriodicWave per direction: blow = brighter (more H2–H4), draw = darker (more fundamental)
Blow reed: H1:1.0, H2:0.88, H3:0.70, H4:0.54, H5:0.40…
Draw reed: H1:1.0, H2:0.72, H3:0.58, H4:0.44, H5:0.33…
Pitch bending: real-time freq×2^(−bendCents/1200) on draw reeds (realistic technique)
Overblown mode: blow reeds bend upward (advanced technique)
Adjacent hole coupling: neighbouring hole rings at 0.030 amplitude if within 2 semitones
Wooden comb body EQ: 6-band (220Hz cavity, 450Hz cover plate, 900Hz mid, 1800Hz reed brightness, 3200Hz upper, 700Hz anti-boxy notch)
Wah filter: auto-wah bandpass at 400–2000Hz, breath-pressure tracked
12 transposable keys (C through B)

Signal Chain

PeriodicWave (blow or draw) → Body EQ → Wah bandpass → Dry/Wet → Destination

Academic References

2001Cottingham, J.P. "Acoustics of the American reed organ." JASA 109(5). — Free reed harmonic spectrum measurements. Basis for the blow/draw PeriodicWave amplitude arrays. The distinction between blow (brighter) and draw (darker) reed spectra is derived from Cottingham's reed orientation analysis.

2003Millot, L. et al. "A few results about the acoustics of mouth organs." JASA 113(4). — Adjacent hole coupling and reed-to-reed acoustic crosstalk. Source of the ±2 semitone coupling threshold and 3% amplitude used in adjacent hole resonance.

2012Adler, S. The Art of Bending Harmonicas. Hal Leonard. — Performance practice: draw bend mechanism (throat constriction lowers pitch), overblown (isolates draw reed to produce overbent blow pitch). Basis for bend and overblown synthesis approach.