Herbie Hancock, voices, speakers and synths
A chapter of Cold Technology, Hot Beats
Acoustic instruments
Your throat and mouth are an analog synthesizer. Your vocal folds are an oscillator. You add noise with your lips and tongue. You modulate the pitch and overtones in your mouth and your chest and sinuses are a resonator.
All other musical instruments work like your voice: oscillator and noise with modulation through a resonator. The components can be made out of wood and animal skins, or metal and plastic. The force driving the vibrating air can be human muscle power or electricity on a wire.
Turning sound into electricity
Sound is rhythmic vibrations in the air.
You can translate rhythmic vibrations from one physical medium to another. You make sound by vibrating your throat, or an animal skin, or a piece of wood or metal, or a speaker cone. You hear sound when the air vibrates tiny bones in your ears.
A microphone simulates the bone in your ear with a thin piece of metal hooked up to a small electric current. When the air vibrates the metal, the current fluctuates in response. 
If you hook up a wire to the piece of metal, and hook the other end to a paper cone, you can reproduce the sound a distance away. You can use vacuum tubes or transistors to make the sound louder. And you can store the electrical fluctuations as grooves in a record, magnetic particles on a tape or numbers in a computer file for later playback.
Analog synthesizers
The theremin was one of the first instruments to make sound by sending electrical sine waves straight to a speaker to produce an unearthly perfect tone. By moving your fingers around in the magnetic field of the theremin’s antennas, the player controls its pitch and volume. More familiar analog synthesizers like the Moog control electromagnetic oscillators from a more user-friendly piano keyboard. Wiring different synthesizer modules together lets you produce complex blends of sine, square and sawtooth waves. Early synthesizers models used vacuum tubes and were floor-to-ceiling hulks straight out of the original Star Trek. Stevie Wonder recorded some of his most famous albums using such a contraption, called TONTO.
Jimi Hendrix and his contemporaries started thinking of the electric guitar as a very sophisticated control surface for the analog synth in the amplifier.
Digital synthesizers
Computers can control electromagnetic oscillators much more precisely than vacuum tubes, and for less money. The computer can blend waveforms together with great precision to create new sounds from scratch. It can also play back digitized recordings and perform modulation on them in real time. Software like Reason can turn any desktop or laptop computer into a sophisticated synth and sample playback system.
It’s weird to be able to produce an infinite variety of different sounds from a single box. It’s doubly weird to be able to convincingly mimic so many other instruments. And it’s triply weird to be able to modulate and warp recorded sounds at will. Digital synthesizers cause some musicians anxiety. Herbie Hancock compared synths to an axe: you can use it to build a house or hurt someone. As Herbie says, the machine doesn’t program itself (yet.)
Playlist
Golden Gate Quartet – “Swing Low, Sweet Chariot”
Eric Dolphy – “God Rest The Child”
Jimi Hendrix – “The Star-Spangled Banner”
Herbie Hancock – “Chameleon”
Stevie Wonder – “Living For The City”
Michael Jackson – “PYT”
Aphex Twin – “Cliffs”
