Audio tech - background and history

Question 1

Describe the acoustics in ancient greek amphitheatres.

Answer 1

• The shell like, convex rear walls reflected and focused sound on the audience.
• The non absorbing surface formed by the stone seats altered the sound waves in a certain way, filtering out some while accentuating others. The “threshold” is usually about 500 hertz, meaning that murmurs originating in the seats are dissipated

Question 2

What was the earliest known device for recording sound?

Answer 2

Phonautograph - 1857 - Leon Scott de Martinville. Was not intended for playback but for sound analysis.

Question 3

What was the first recording AND playback device?

Answer 3

Phonograph - 1877 - Thomas Edison

Question 4

What did Emile Berliner develop?

Answer 4

The Gramophone in 1888 - similar groove technique to the phonograph, but uses a wax disk instead of tin foil wrapped around a cylinder.

Question 5

What did the gramophone enable?

Answer 5

Mass distribution of media (the gramophone record).

Question 6

List the technological improvements of the gramophone.

Answer 6

• Longer duration (larger, double-sided; 7” single, 12” EP/LP)
• Electric-driven motors (33 1/3, 45, 78 rpm)
• Stereo Sound

Question 7

What happened to the gramophone from the 1920s?

Answer 7

Electrical induction (pick-ups) - improved quality (fidelity) and loudness.

Question 8

What happened to the gramophone from the 1950s?

Answer 8

Transistor-based models
 - enabled portable players

Question 9

When was the Telegraphone invented?

Answer 9

1898 - first magnetic (not purely mechanical) recording device.

Question 10

When was magnetic tape first developed?

Answer 10

1927 by Fritz Pfleumer. Thin paper coated with iron oxide powder (replaced coil of wire).

Question 11

Describe the advantages and disadvantages of magnetic tape.

Answer 11

• Easy and compact to store
• Easy to cut/edit (with scissors)
• Harder to distribute (until plastics)

Question 12

Describe the musical Telegraph, when it was invented and by who.

Answer 12

Elisha Gray 1874 - multiple telegraph (morse code) transmitters at different frequencies, triggered by piano keys.

Question 13

Describe the Telharmonium, when it was invented and by who.

Answer 13

Thaddeus Cahill - 1896 - uses tone wheels (large metal cogs that produce magnetic field variations).

Question 14

Describe the Theremin, when it was invented and by who.

Answer 14

Leon Theremin - 1920 - works without touch. Two ‘antennas’ detect capacitance of human body. One hand controls the frequency (pitch), the other amplitude (loudness). Sound produced by vacuum tubes (different timbres possible).

Question 15

When was analogue synthesis developed?

Answer 15

In the 60s and 70s from early computers and lab test equipment.

Question 16

What does analogue synthesis use voltage for?

Answer 16

To represent sound.

Question 17

What does digital audio represent sound as?

Answer 17

1,s and 0,s rather than continuous voltage.

Question 18

Describe the Yamaha DX7.

Answer 18

• Made in 1983
• Uses frequency modulation (FM) developed by John Chowning to create complex sounds from simple combinations of tones.
• First compact ‘affordable’ synth.
• First MIDI synth

Question 19

Compare digital and analogue systems in terms of sampling.

Answer 19

Compared to analog, digital systems are ideal 
for storing, editing, and playing recoded sound.

Question 20

What is sampling based on?

Answer 20

Recording
 individual notes or sound extracts
and playing them back on-demand.

Question 21

What was the first polyphonic digital sampler?

Answer 21

Fairlight CMI (1979)

Question 22

When did software synthesis come into place?

Answer 22

Late 90s - Plugins replaced external hardware.

Question 23

What was an influential programming language for music?

Answer 23

Music-N (from 1957 to present). Pioneered by Max Matthews. Culminated in CSound and Max (1980s-). Used for audio synthesis, algorithmic composition etc.