Sound projection mock questions

Question 1

If a loudspeaker is mounted in the front panel of a regular rectangular box with no further interventions, the resulting device is called:

Answer 1

An infinite baffle

Question 2

Three key benefits by matching a loudspeaker to a ported cabinet? What is the name of the resonator that is formed in doing so?

Answer 2

Increased efficiency, increased bass response, flatter response at all frequencies. Helmholtz resonator.

Question 3

maximum bandwidth achieved by a moving coil speaker, and the minimum number of moving coil speakers required to cover the full human frequency hearing range? name of the device that will split incoming audio into separate frequency bands

Answer 3

5 octaves, 2 speakers, crossover

Question 4

five benefits that physical interventions can bring. What are they?

Answer 4

Increased efficiency, increased sensitivity, improved phase
coherence, increased directionality, increased bass response.

Question 5

What is the typical range of efficiency of a moving coil speaker at low frequencies before any interventions?

Answer 5

1-5%

Question 6

In a mixing console, there are typically two subsystems that can route multiple channel signals out of the desk, and which are accessed in the channels themselves. What are they called?

Answer 6

Auxiliaries and groups.

Question 7

The four functions typically found before a signal reaches the channel EQ, insert or fader. What are they?

Answer 7

Gain, Phase reverse, High Pass Filter, Pad

Question 8

If a loudspeaker has a quoted sensitivity of 85dB @1 watt/metre, how many decibels will it produce, measured at the same distance, with the same input signal, if it is powered by a 100 watt amplifier? Include the formula used to solve this question in your answer.

Answer 8

85dB + 10(log 100/1)
= 85+10(2)
= 85+20
= 105 dB

Question 9

name of loudspeaker that contains two moving coils of identical specification mounted horizontally? What is the benefit of such a design? And what part of the audio spectrum is affected (Low, mid or high?)

Answer 9

A dipole speaker. It will narrow the directionality of mainly mid
range signals

Question 10

What is the purpose of a phase plug, and how does it achieve this?

Answer 10

Improves phase coherence in an arc in front of the speaker. This is achieved by equalising the path length to the outside world travelled by weaves emitted on opposite sides of the speaker.

Question 11

In a mixing console, the EQ, insert and auxiliary have options to be taken pre or post other elements of the signal path. Note which control has which option.

Answer 11

-EQ can be pre/post the: Insert
-Insert can be pre/post the: EQ
-Auxiliary can be pre/post the: Fader

Question 12

Label the four indicated parts of the moving coil speaker

Answer 12

((look at pic))