1. Basics of Sound Systems

Question 0

What are the 7 types of input transducers?

Answer 0

Air pressure/ velocity mics: sound waves in air -> audio signal in mic cable
Contact pickups: sound waves in dense mediums -> audio signal
Magnetic pickups: fluctuating waves of magnetism -> audio signal
Tape heads: fluctuating magnetic fields -> audio signal
Phonograph pickups: physical movement of stylus -> audio signal
Laser pickups: imprinted patterns on disc -> digital data stream translated by DAC (digital to analog converter)
Optical pickups: variations in the density/ transparency of photographic film -> audio signal

Question 1

What is the practical model of a sound system?

Answer 1

Input transducer ->
signal processing: preamp to line level, EQ, mixing to produce a single line level output ->
Output transducer (converted by loudspeaker)

*consoles output is connected to power amp which boosts console’s line level (.1-100 milliwatts) out put signal to suitable level to drive the loudspeaker (.5 to 500 watts)

Question 2

Woofer loudspeakers

Answer 2

6k (down to 1.5k)

   - cone drivers; 2-5 inches
   - compression drivers; 1.5- 4 inches

Question 3

Midrange loudspeakers, “squawkers”

Answer 3

500Hz- 6k

 - cone driver; 5-12 inches
 - compression driver; 2.5- 4 inches

Question 4

Tweeters

Answer 4

> 6k (down to 1.5k)

  - cone drivers; 2-5 inches
  - compression drivers; 1.5- 4 inches

Question 5

Full range loudspeakers

Answer 5

100Hz- 10/15k

Woofer and tweeter in the same enclosure

Question 6

Subwoofers

Answer 6

Down to 20-30 Hz

-cone driver; 15-24 inches

Question 7

Super tweeters

Answer 7

> 10k

-compression or piezoelectric drivers