Sound projection 2 Flashcards
The Master, Monitor and Solo Busses.
- The master bus always carries the stereo mix and feeds the stereo recorders used when mixing down.
- The monitor bus drives the studio loudspeakers and usually monitors the master bus.
- The solo bus over-rides into the monitor bus when selected.
Solo Modes
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
Ways outboard is connected to a desk
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.
Group Inserts
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.
Gain structure
refers to setting proper input gain to achieve the best signal to noise ratio
Connecting via an auxiliary
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
Connecting via an insert
For modifying an entire sound, generally EQ, compression or gating.
Digital Vs Analogue
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.
Virtual channels
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.
Mic set up for Speaker sensitivity
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.
Speaker sensitivity
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
Speaker dispersion
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.
Predicting output from a given input.
If the input is 50 watts of power, the power level will be: 100 dB + 10 x (log 50/1) = 116.98 dB.
Di Pole speakers
Emits sound in two different directions and phase cancels audio from a central position to create a more binaural effect.
Bi Pole speakers
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.
Path of a channel signal through the desk
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.
Loudspeaker
is an electro-acoustic transducer; which converts an electrical audio signal into a corresponding sound.
Dynamic speaker
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.
Problems with dynamic/moving coil speaker
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
Baffle speaker
- 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.
- 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.
Infinite Baffle
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.
Physical Interventions
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
Horns
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.
Compression Driver/chamber
Placed just before the throat of a horn, compression drivers compress air and produce an increase in sound efficiency, especially in high frequencies.
