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The reese is two saws a few cents apart, and every harmonic beats at its own multiple of the detune. At 15 cents on A1 the fundamentals drift round each other every 2.09 s and the eighth harmonic beats 3.83 times a second, both read off the sound. The lowpass decides the fastest beat you hear: 5 Hz closed, 12 Hz open, and at 30 cents open it passes 15 Hz and the growl becomes grit. Play it, or let it play a bar of drum and bass.
The 808 is one sine with a pitch envelope. It starts at 147 Hz and lands on 49 in 155 ms, and the tail takes 2.4 s to fall 60 dB. A phone speaker plays 1% of it, and 84% of that is the first 50 ms. Clipping it hard buys the phone under 3 dB. Playing it an octave up buys 10. Play it on the keys, or let it play itself.
The lo-fi knobs, measured. Eight bits puts the noise floor 48.9 dB down, a tenth off the textbook figure, and turns a note at -40 dB into 27% distortion. Four bits gives 25 dB and that quiet note comes out as nothing at all. Dither brings it back as a tone in hiss for 4.9 dB of noise, and holding samples at 6 kHz grows a 1 kHz tone two images at 5 and 7 kHz, -14 and -17 dB, where the sinc says they should be.
Most systems play the bass in mono, and a bass widened for headphones pays for it there. A 10 ms delay on one side reads as out of phase and takes 16 dB off a 55 Hz bass in the sum. A detuned pair pumps in mono every 1.6 s, 54 dB deep. Sum and difference combs are as wide as either and lose nothing at all, measured.
A chord's shimmer is its tuning. In equal temperament the third of a C major is 13.7 cents sharp of 5:4, so the root's fifth harmonic and the third's fourth miss by 10.4 Hz and beat that fast, measured off the sound, swelling 15 dB. In just tuning the same pair sits dead still. A minor third beats faster, and a 250 ms stab still holds two and a half swells of it.
Distortion is a curve, and everything people say about warm and harsh is a claim about its shape. Measured at the same distortion, a soft clip's harmonics fall 39 dB an octave and a hard clip's fall 12. Even harmonics need an asymmetric curve, and on two tones they cost a note two octaves down that nobody played, at -29 dB.
Noise has a colour, and the colour is a number: white is flat, pink falls 3 dB an octave, brown falls 6, measured. A hi-hat is what noise is for, and the 808's is six square waves chosen to share no harmonic. How little pitch that leaves is a number too, 45% for the six and 16% for the finished hat.
Sidechain pumping, the bass ducking under every kick, is done for loudness. Measured at the same peak, it buys about half a loudness unit at best, costs 1.5 without lookahead, and a loudness meter shows 2.4 LU of a 15 dB duck. The last part of the series, and the one where the reason turns out to be the groove.
A pulse wave has one knob, its width, and the width decides which harmonics do not exist. At half it is a square and every even harmonic is gone. At a third, every third. At a quarter, every fourth. Measured, exactly, and then the naive digital square measured against the exact one.
A saw through a resonant lowpass with the cutoff swept by an LFO at the tempo. Sweep it in hertz and the wobble sounds open 80% of the time, because the ear hears octaves. And however you sweep it, the resonance cannot keep up, 3 dB short at half notes and 6 dB short at sixteenths.
Seven saws spread across thirty cents is the sound of every trance lead. Everyone argues about how many voices. Measured, the movement is about 2 dB whether you stack two or sixteen, and what more voices buy is that the shimmer never repeats, but only if the spacing is uneven. Evenly spaced, seven voices loop every 3.1 seconds.
A phone speaker hears one per cent of a clean 808, and 93% of that is the first 60 milliseconds. Saturation does not bring the energy back, it moves it later into the body of the note. Drive makes a sub last on a phone. It does not make it louder.