Harmonic Synthesis is an iPad App to create sounds that can be used as a bench oscillator, for demonstrating and experiencing the full range of human hearing, and to help understanding audio synthesis. It sets up its sounds via button presets for different waveform shapes (sine, square, triangular, sawtooth and pulse) and it allows the user to adjust the amplitudes of the first 16 harmonics using sliders and to hear the result. In this version, a new set of buttons has been added to enable harmonic levels to be set in terms of decibels per octave (dB/octave) roll-off (0, -3, -6, -9, -12, -15, -18 dB/octave). Vibrato and tremolo, both with user-adjustable rate and extent, are available along with sliders for fundamental frequency or pitch (20Hz-20kHz log or linear), volume and a "Play"/"Stop" button. As the fundamental frequency is increased, sliders for any harmonics that go out of the hearing range (higher than 20 kHz) are removed.
A set of 12 selector buttons enables preset harmonic series to be produced as follows:
- Sinewave
- Harmonics 1-6
(pitch perception demonstrations) - Harmonics 9-16
(pitch perception demonstrations) - Odd harmonics
- Amplitudes falling linearly
- Amplitudes rising linearly
- Square wave
- Triangular wave
- Sawtooth wave
- Pulse wave (all harmonics maximum)
- Random amplitudes
- All harmonics off
A new set of 8 radio buttons is available as a
switchable alternative to those above as follows:
- 0dB/octave
- -3dB/octave
- -6dB/octave
- -9dB/octave
- -12dB/octave
- -15dB/octave
- -18dB/octave
- All harmonics off
Hearing awareness: Please be aware that listening to loud sounds can damage your hearing and use HarmSyn with care and due consideration for your own ears as well as the ears of others. More details about human hearing can be found in: Howard and Angus, Acoustics and psychoacoustics, 4th Edition, Oxford: Focal Press, 2009, ISBN: 978-0-240-52175-6.
HarmSyn is available NOW - click on the link below
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