Sound projection 2

Question 1

The Master, Monitor and Solo Busses.

Answer 1

1. The master bus always carries the stereo mix and feeds the stereo recorders used when mixing down.
2. The monitor bus drives the studio loudspeakers and usually monitors the master bus.
3. The solo bus over-rides into the monitor bus when selected.

Question 2

Solo Modes

Answer 2

SIP - Solo in place. The stereo position is dictated by the pan knob, post fader level
PFL - Pre fade listen. Solo is generally mono
AFL - After fade listen. Solo is generally mono

Question 3

Ways outboard is connected to a desk

Answer 3

Outboard gear, such as effects/signal processors can be connected to a mixing desk in several ways:
1. Via auxiliary send and return circuit
2. Via insert send and return loops in individual channels.
3. Via group inserts, or inserts into the master buss.

Question 4

Group Inserts

Answer 4

Used to place insert type effects over multiple channels. Typically for compressing an entire drum kit, gating a group of backing vocal tracks, or EQ-ing a string section.

Question 5

Gain structure

Answer 5

refers to setting proper input gain to achieve the best signal to noise ratio

Question 6

Connecting via an auxiliary

Answer 6

Makes multiple channels access a processor, for example when adding reverb to numerous instruments. The auxiliary is a buss, and as such can be prone to noise. We may be able to automate (or just play in real time) the switching in of auxiliary sends or returns

Question 7

Connecting via an insert

Answer 7

For modifying an entire sound, generally EQ, compression or gating.

Question 8

Digital Vs Analogue

Answer 8

Advantages of digital = processing, recall and automation. Can be better than analogue but very expensive.

Advantages of analogue = real time control, more channels and outputs/inputs.

Question 9

Virtual channels

Answer 9

are a type of software-based channel that allows audio to be processed in a digital domain before it is sent to the physical mixing desk’s inputs.

Question 10

Mic set up for Speaker sensitivity

Answer 10

Place a measurement microphone one meter away from the front of the speaker. Then connect an amplifier to the speaker and play a signal with a level adjusted at one watt of power to the speaker. The results (measured in dB) from the microphone will be the speakers sensitivity.

Question 11

Speaker sensitivity

Answer 11

a speaker with a quoted sensitivity of 87dB, will produce that level of acoustic power, it’s not necessary to have hundreds of watts on tap to produce a loud sound… just very sensitive speakers

Question 12

Speaker dispersion

Answer 12

High frequency content drops away as we move further from the on axis position (the front Centre of the speaker). Increased distance creates loss through the inverse square law.

Question 13

Predicting output from a given input.

Answer 13

If the input is 50 watts of power, the power level will be: 100 dB + 10 x (log 50/1) = 116.98 dB.

Question 14

Di Pole speakers

Answer 14

Emits sound in two different directions and phase cancels audio from a central position to create a more binaural effect.

Question 15

Bi Pole speakers

Answer 15

When the sounds of both drivers in a bipole speaker converge, they don’t cancel each other out. They’re more practical but wont sound as binaural as dipole.

Question 16

Path of a channel signal through the desk

Answer 16

Channel Routing
Group fader
Group output
Monitor input
Stereo output

We can listen to the signal at all these points to check its quality:- by using the solo buss.

Question 17

Loudspeaker

Answer 17

is an electro-acoustic transducer; which converts an electrical audio signal into a corresponding sound.

Question 18

Dynamic speaker

Answer 18

operates by using a diaphragm that is attached to a voice coil, which is suspended within a magnetic field. When an audio signal is passed through the voice coil, it creates a magnetic field that interacts with the fixed magnetic field of the speaker. This causes the voice coil and attached diaphragm to move back and forth rapidly, producing sound waves that are propagated through the air.

Question 19

Problems with dynamic/moving coil speaker

Answer 19

May exhibit problems transmitting low frequencies when suspended in mid air. This is because the high pressure zone in front of the speaker and the low pressure zone behind the speaker can phase cancel each other out

Question 20

Baffle speaker

Answer 20

1. is a type of loudspeaker that is designed to be mounted on a rigid panel, which serves as a physical barrier between the front and back of the speaker.
2. The baffle prevents sound waves from the rear of the speaker cancelling sound waves from the front, this however can result in a loss of bass/overall volume.

Question 21

Infinite Baffle

Answer 21

A baffle can be made infinitely large by forming an enclosure around the loudspeaker. However, the box will produce resonance at frequencies relating to its internal dimensions, similar to the body of a guitar.

Question 22

Physical Interventions

Answer 22

Horns, Phase Plugs and Compression drivers are all Physical Interventions. There purpose is to improve transmission characteristics, such as:
-Greater sensitivity
-Greater efficiency
-More even frequency response
-More/less directionality
-More even phase response

Question 23

Horns

Answer 23

has either a conical or rectangular cross section.
-slow flare rate horn = wider dispersion of sound + lower efficiency.
-fast flare rate horn = narrower dispersion + higher efficiency.

Question 24

Compression Driver/chamber

Answer 24

Placed just before the throat of a horn, compression drivers compress air and produce an increase in sound efficiency, especially in high frequencies.