Small experiments in sound, perception and arithmetic.

Each one runs in your browser, and each one rests on something I measured. About half the time the measurement was the surprise.

104 shipped72 make noise54 larger buildsall playable on a phone

105
The Jump-Up Bass
A Reese is two saws a few cents apart, so every harmonic is two lines with nothing at all between them: 84 dB of nothing at the sixth. Distortion doesn't add harmonics to it, the count is pinned at its ceiling before the first clipper even runs. What it does is put lines where there were none, and by the third nonlinearity the gap is within 17 dB of the lines either side of it. This one is also the first day where the sound isn't code: it's a patch, thirteen nodes of data, and the five steps you walk through are worked out from the signal path rather than written by hand.
sounddeepRecipes 2/12audio synthesis web-audio
103
The Moog Bass
The first of twelve basslines built a step at a time, and the step that matters turns out to be the filter you can't get from Web Audio. A Moog's ladder is four one pole stages with feedback around all four, and that feedback subtracts the input, which is what eats the bass: for an 8.5 dB resonant peak it pays 10.4 dB of fundamental while the peak itself rises 12.1 dB. Two cascaded BiquadFilterNodes put up the same peak within 0.1 dB and pay nothing at all, so at matched peaks the ladder sits 12.5 dB further down. First of twelve.
soundbuildRecipes 1/12audio synthesis web-audio
102
The Sidechain
The pump of house is a compressor on the pad keyed from the kick, and the release knob is the sound. Measured off the pad's own level: a kick every 469 ms pushes it down 16 dB, and with a 150 ms release it's more than 3 dB down for 82% of every beat, back in 378 ms. At 50 ms that's 51% and 220 ms, a dent. At 400 ms it never gets back, a quieter pad. The worklet compressor rendered offline agrees. Twelfth of twelve.
soundbuildPatches 12/12audio synthesis web-audio
101
The Organ Bass
The M1 organ bass under half of house is a Hammond in software: drawbars that hold, a percussion harmonic that comes in 17 dB above them and decays in 150 ms, and a click of 31 dB of high frequency in the first five milliseconds. All three read off the sound, the percussion to within 10 ms of its setting. It fires only on a note played alone, so a legato phrase gets it once, and that's the feel.
soundbuildPatches 11/12audio synthesis web-audio
100
The Snare
A 909 snare is two tones at 180 and 330 Hz and a burst of highpassed noise, and the tones decay faster than the noise, so every hit stops being a drum and becomes a hiss at some moment. Measured off the sound, that moment is 84 ms at half snappy, 203 at a quarter, and never arrives at full because the noise leads from the first millisecond. The two decays predict 91 and 202. Play it, or let it play the two and four.
soundbuildPatches 10/12audio synthesis web-audio
99
The Clap
A clap is four bursts of noise 10 ms apart and a tail. A drum machine gates one noise source, so every burst is fresh. A sampler layers one burst on itself, so every burst is the same noise, and a sound that repeats every 10 ms wears a comb of peaks every 100 Hz. Measured: the copied clap repeats exactly and its comb is 23 dB deep, the fresh one never comes closer than a third of the way and has no comb at all. Same envelope, same ear, different spectrum.
soundbuildPatches 9/12audio synthesis web-audio
98
The 909 Hat
A 909 hat is six square waves at 205, 254, 370, 304, 523 and 800 Hz, frequencies picked to share no period. Measured by sliding the sound against itself, the closest it ever comes to repeating is 49% different. Snap the same six onto a 50 Hz grid and it repeats exactly every 20 ms, and a tone appears where the metal was. Play it, tune it, or let it play house hats.
soundbuildPatches 8/12audio synthesis web-audio
97
The Acid Line
A 303 slide is a lag on the pitch in semitones, so it takes the same time whatever the interval. Measured off the sound, a semitone and an octave both get 63% of the way in 59.8 ms and 95% in 180 ms, and an octave covers twelve times the ground in that time rather than taking twelve times as long. The accent opens the filter 1.4 octaves and adds 3.5 dB, and leaving the level out makes an accented note measure quieter than a plain one.
soundbuildPatches 7/12audio synthesis web-audio
96
The Hoover
Pulse width does not filter, it deletes. A rectangle of width d has harmonic h at four over pi h times the sine of pi h d, so harmonic h is exactly silent whenever d is a multiple of one over h. Measured on a real rectangle against that formula, every harmonic lands within a thousandth of a dB, and sweeping the width takes each harmonic to silence exactly floor(h/2) times between nothing and a half. Play it, or let it play rave stabs.
soundbuildPatches 6/12audio synthesis web-audio
95
The Supersaw
Seven sawtooths spread across a detune, and the seven lines around every harmonic get h times further apart as you go up. Measured on A3 at 40 cents, the fundamental swells 53 dB and the beating dies at harmonic 36, where the voices are 183 Hz apart, against 43 predicted from where the clusters touch. At 80 cents it dies at 18 and at 10 cents it never does. That's why a supersaw beats at the bottom and hisses at the top.
soundbuildPatches 5/12audio synthesis web-audio
94
The FM Bass
Two sines, one modulating the other, and the spectrum is a Bessel function. Measured against the arithmetic at every ratio and index the page offers, the worst sideband is 0.18 dB out. At an index of 2.405 the first zero of J0 takes the note out of its own sound, 80 dB down while the sound stays loud, and a decaying index passes through that null 62 ms into every note, predicted at 61. At a ratio of 1 or 2 the folded sidebands land back on the note and the null only half happens.
soundbuildPatches 4/12audio synthesis web-audio
93
The Wobble
A wobble is a saw through a resonant lowpass swept by a tempo locked LFO, and it doesn't sweep, it steps. The filter peak can only land on a harmonic of the note, so on a 55 Hz saw it climbs a staircase of 32 harmonics from the third to the 45th, a fourth wide at the bottom and 0.39 of a semitone at the top, going round 4.6 times a second on an eighth note at 140. Sharp resonance lifts each step 18 dB, soft lifts it 6. Play it, or let it play a bassline.
soundbuildPatches 3/12audio synthesis web-audio