Unit 2.2

Question 1

Reflections (two ways sound moves)

Answer 1

1. direct sound - from source to ears
2. reflected sound - hitting something first, then to ears (takes longer)

Question 2

Time delay (& ITDG)

Answer 2

• reflected sound is delayed
• high reflection levels (high delay) approx. 50ms
• initial time delay gap (ITDG) = the time at which the first reflection is heard after the direct sound

Question 3

Best concert halls have an ITDG of

Answer 3

less than 25ms (greater then 35ms introduces a lack of clarity)

Question 4

Clarity index

Answer 4

measures the ratio of early/late reflections
- early reflections: less than 80ms
- late reflections: greater than 80ms

Question 5

Shoebox concert halls

Answer 5

• ideal width 15-25 m
• irregularities in the room lead to more uniformly dispersed sound
• increases lateral reflections and immersion

Question 6

Reverberation Time

Answer 6

RT = time for sound to drop 60dB
- sound is absorbed by a lot of things and can effect the sound