42 lines
1.9 KiB
Matlab
42 lines
1.9 KiB
Matlab
function x = generate_horn(amplitude, frequency, phase, fs, duration, duty)
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% GENERATE_HORN: returns a matrix of sampled waveform similar to
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% a horn.
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% CONTRIBUTORS:
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% Brandon Roberts: Original author
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% MuseScore: Reference source for overtone information
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% DOCUMENTATION:
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% phase shift is in number of periods
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% fs is the sampling frequency: how many sample points per second
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% duration is time in seconds
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% duty does not apply for instruments
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% setup needed variables
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n = fs * duration; % total data points
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dt = 1 / fs; % space between samples
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% initialize template time scale
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t = [1:n].*dt - phase;
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f = frequency .* (1 + 0.0002 .* sin(4.*pi.*t)./t); %frequency vibrato
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% generate proper fundamental and overtones
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x = (0.21707879.*amplitude .* sin(2.*pi.*f.*t)) ... %fundamental (first partial)
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+ (amplitude .* sin(4.*pi.*f.*t)) ... %second partial
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+ (0.234667056.*amplitude .* sin(6.*pi.*f.*t)) ... %third partial
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+ (0.088606568.*amplitude .* sin(8.*pi.*f.*t)) ... %fourth partial
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+ (0.0864485981.*amplitude .* sin(10.*pi.*f.*t)) ... %fifth partial
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+ (0.0275181724.*amplitude .* sin(12.*pi.*f.*t)) ... %sixth partial
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+ (0.0472968588.*amplitude .* sin(14.*pi.*f.*t)) ... %seventh partial
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+ (0.0246462876.*amplitude .* sin(16.*pi.*f.*t)) ... %eighth partial
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+ (0.00816134476.*amplitude .* sin(18.*pi.*f.*t)) ... %ninth partial
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+ (0.00691199377.*amplitude .* sin(20.*pi.*f.*t)) ... %tenth partial
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+ (0.00494872793.*amplitude .* sin(22.*pi.*f.*t)) ... %eleventh partial
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+ (0.0048026999.*amplitude .* sin(24.*pi.*f.*t)) ... %twelth partial
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+ (0.00335864486.*amplitude .* sin(26.*pi.*f.*t)) ... %thirteenth partial
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+ (0.00262850467.*amplitude .* sin(28.*pi.*f.*t)); %fourteenth partial
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x = x .* (1 + 0.05 .* sin(2.*pi.*t)); %volume vibrato
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end
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