Music 1770: Intro to Music Technology

Keywords for History of sound recording, part I
(Lecture #8)

Before sound recording

Music notation: mnemonic vs. prescriptive vs. descriptive
Mechanical instruments (as early as 9th C) with storable programs
Transducers
Hearing
Tin can telephone

Sound Recording Eras

Acoustic/Mechanical Era (1860-1925)
Electrical Era (1925-45)
Magnetic Era (1945-1975)
Digital Era (1975- )

Acoustic or Mechanical Era (to 1925)

Recording
Phonautogram 1860s
Analog: recording is a continuously varying analog to continuously varying sound pressure
Phonograph 1877 (mechanical, mono)
Stylus cuts groove into waxed cyclinder or disc
Playback: reverses the process (can even use same stylus)
Nothing electric; all mechanical
Horn both focuses (recording) and “amplifies” (playback) but doesn’t add power
Analog
Hill-and-dale to side-to-side; cylinder to disc

Electronic Era

Microphone
All types (condenser, dynamic, ribbon) same basic principle: motion of material within an electric field
Exceptions: contact (piezoelectric), optical
Electric sound signal
Loudspeaker
Recording: still mostly discs (shellac, vinyl)
Exception: sound-on-film (optical soundtrack)
Editing: very limited

Magnetic Era

Wire
Tape
Tape hiss: a function of iron oxide particle size (a kind of pre-digital quantization error)
can be reduced by higher speed, wider track, or finer particle size
Splicing
Multitrack: stereo, 3-track, 4-track, and beyond
Non-destructive overdubbing on blank tracks: “tracking”

Side note: stereo vinyl

L and R coded into “mid” and “side”
Mid is the sum of the L & R signal, divided by two: M = (L+R)/2
Side is the difference between the L & R signal, divided by two: S = (L-R)/2
To decode back to stereo: L = M+S; R = M-S

links for further information

Wikipedia on:

Preparing your music for LP mastering: recordtech.com/prodsounds.htm

More about Guido d'Arezzo, the guy who invented modern music notation

More about the Banu Musa, the brothers who made some of the first automated music machines