Dynamic Processors & EQs Flashcards
Gate/expander
Allows the signal that is above the selected threshold to pass through to the output at unity gain and without dynamic processing
Gates threshold (trigger)
Sets the level at which the gate will open and allow signal at the input to pass through through to the output
Gate parameters
Set the level amount and if the waveform passes above it, it allows it in, and if it’s below it, it attenuates it
When a signal opens the gate, what sounds come through?
Everything
What does gating help with?
Helps remove unwanted signals
Why is gating “irrelevant” in digital audio?
Because you can just cut out areas that have bleed
What is gating typically used for in digital audio?
Creative uses
Gate: Attack
Sets how fast the fate fully opens once the signal crosses the threshold
Gate: Hold
Set the amount of time the fate remains open once the input falls below the threshold
Gate: Release
Sets the amount of time it takes the gate to close, once the input falls below the threshold level AND the hold function has expired
What do the gate functions match? (attack, etc)
Envelopes of waveforms
Attenuation (Range, depth)
The amount of attenuation applied to the input signal once it falls below the threshold
What happens if range is set at around -60dB?
It’s essentially more like a mute button, and having it mute on and off causes the instrument coming through to sound fake and unnatural
When is a bit of ‘bleed’ okay?
It’s okay to let some bleed in and let it attenuate smoothly rather than shutting the gate off quickly and causing the sound to be unnatural
Noise gate attenuation amount
Full attenuation
Expander attenuation amount
Partial attenuation
Where is an example that gating is necessary?
Live sound (used all the time) and analog editing (for those who actually do that still lol)
Compressor/limiter
A device that puts gain reduction to manipulate or control the dynamic range of an audio signal
Compressor threshold
When the input signal exceeds a pre-determined level, the compressor’s gain is reduced and the signal is attenuated
Gates vs Compressor thresholds
Gates attenuate signal when dB is BELOW the threshold, until dB goes ABOVE and the gate opens to let signal through, aka. doesn’t let softer sounds in
Compressors leave signal as is when dB is BELOW the threshold, until dB goes ABOVE and then it is attenuated, aka. doesn’t let loud sounds out
Signal path in a dynamic processor
Signal is split between two paths: audio and side-chain
Side-chain
Where the signal level is measured by a voltage detector (threshold)
Ratio
The amount of input dBs ABOVE the threshold, versus the amount of output dBs ABOVE the threshold
What you put in versus what you get back
Unity gain
1:1 ratio
4:1 compression becomes more like _____
A limiter
Compressor vs Limiter
Primary difference is the RATIO. Generally, the higher the ratio, it is more of a limiter, while a lower ratio is compressor
Gain reduction
Threshold + ratio will result in gain reduction
Compressor: Attack
The amount of time it takes for the compressor’s gain to be reduced once the signal crosses the threshold
Compressor: Release
The amount of time it takes for the compressor’s gain to return to its original level
Release side effects
If the release is too fast: pumping or breathing - a rapid rise in noise floor due to too fast of a release time for the program material
If the release is too slow: over-compression (the compressor never lets up)
Output/make-up gain
Compensates for gain reduction that occurs post-compression, that makes the compressed signal louder (match it to the input signal level)
What also gets louder when you turn up output gain?
Noise floor turns up with it - this rarely poses an issue when the whole mix is playing together as it will be masked
4 steps to setting up any compressor
- Input - insert patch
- Set ratio
- Lower the threshold to achieve gain reduction
- Match output gain to input level
Audio Equalisation
Device that enables the engineer to exercise control over the harmonic/timbral content of a live or recorded sound
Timbre
Term that describes characteristics of sound outside of pitch and volume. It is the harmonic and musical content of a sound that differentiates itself from another sound producing the same pitch, regardless of volume.
What does not have any timbre?
Sine waves (simple and pure tone)
Reasons to EQ
To correct or improve specific problems in a “live” signal, a recording, or within a room