Dynamics ProcessorsDynamics Processors

Riding the waveRiding the wave

What are dynamics?What are dynamics?

““In music, In music, dynamicsdynamics normally refers to the normally refers to the volume of a sound or note”volume of a sound or note”

- http://en.wikipedia.org/wiki/Dynamics_%28music%29- http://en.wikipedia.org/wiki/Dynamics_%28music%29

Volume:Volume: “ “the softness or loudness of the softness or loudness of sound” sound” – Essential Dictionary of Music. Harnsberger, L.. Alfred Publishing Co., Inc. 1997 – Essential Dictionary of Music. Harnsberger, L.. Alfred Publishing Co., Inc. 1997

““dynamic range dynamic range is the difference between is the difference between the quietest and loudest volume of an the quietest and loudest volume of an instrument, part or piece of music.” instrument, part or piece of music.”

- http://en.wikipedia.org/wiki/Dynamic_range#Music- http://en.wikipedia.org/wiki/Dynamic_range#Music

Peak vs. RMSPeak vs. RMS

A peak is the highest absolute level of a A peak is the highest absolute level of a signal (“maximum”)signal (“maximum”)

RMS – Root Mean SquareRMS – Root Mean Square .707 of peak value.707 of peak value ““average” level of a signalaverage” level of a signal

Your perception of volume usually Your perception of volume usually corresponds to the average level of a corresponds to the average level of a signal as opposed to the peak level signal as opposed to the peak level

Parts of musical soundsParts of musical sounds

A instrument’s sound can be analyzed by how it behaves over A instrument’s sound can be analyzed by how it behaves over time. time.

AttackAttack - the onset of the sound, sometimes called an - the onset of the sound, sometimes called an attack attack transienttransient

DecayDecay - after the initial transient, there is often a drop-off in the - after the initial transient, there is often a drop-off in the amount of energy in the sound.amount of energy in the sound.

SustainSustain - After the energy from the attack is spent, the instrument - After the energy from the attack is spent, the instrument may ring on for some timemay ring on for some time

ReleaseRelease - the behavior of the instrument after the note is no - the behavior of the instrument after the note is no longer being held by the musicianlonger being held by the musician

These terms are derived from These terms are derived from synthesissynthesis

ADSR EnvelopeADSR Envelope

htp://www.midi.org/about-midi/tutorial/tutor.shtmlhtp://www.midi.org/about-midi/tutorial/tutor.shtml

ADSR of a snare hitADSR of a snare hitAttack

Decay

Sustain“Release”

Dynamics ProcessorsDynamics Processors

Operate on the dynamic range of a signalOperate on the dynamic range of a signal

Envelope generator – VCAEnvelope generator – VCA

Automatic volume controlAutomatic volume control

Two basic typesTwo basic types Compressor (Limiter) – reduces dynamic Compressor (Limiter) – reduces dynamic

rangerange Expander (Gate) – enlarges dynamic rangeExpander (Gate) – enlarges dynamic range

Typical Controls on a Dynamics Typical Controls on a Dynamics ProcessorProcessor

ThresholdThreshold – the signal level at which the – the signal level at which the processor will begin to workprocessor will begin to workRatioRatio – the amount of signal reduction as – the amount of signal reduction as compared to the original signal level over the compared to the original signal level over the thresholdthresholdAttackAttack – the length of time the processor will – the length of time the processor will take to apply (comp) or reduce (gate) gain take to apply (comp) or reduce (gate) gain reductionreductionReleaseRelease – the length of time the processor will – the length of time the processor will take to give back (comp) or take back (gate) the take to give back (comp) or take back (gate) the gaingainOutputOutput – make up (or reduce) overall signal – make up (or reduce) overall signal levellevel

Expanders/GatesExpanders/Gates

Expanders Expanders increaseincrease the dynamic range of the dynamic range of a signal by reducing the level of the signal a signal by reducing the level of the signal belowbelow the threshold the threshold

Expanders and gates are often used for Expanders and gates are often used for noise reduction and/or to reduce the noise reduction and/or to reduce the amount of “bleed” on a channel amount of “bleed” on a channel

(e.g. drum mic’s)(e.g. drum mic’s)

Gate = automatic mute switch (sort of…)Gate = automatic mute switch (sort of…)

Compressors/LimitersCompressors/Limiters

Compressors Compressors decreasedecrease the dynamic range of a the dynamic range of a signal by reducing the level of the signal signal by reducing the level of the signal aboveabove the thresholdthe threshold Compressors actually make things “softer”Compressors actually make things “softer”

Compressors are often used make a signal Compressors are often used make a signal louderlouder By reducing By reducing peakpeak signal level, it allows you to increase signal level, it allows you to increase

the the averageaverage level by bringing up the overall gain level by bringing up the overall gain

Limiter = compressor on steroidsLimiter = compressor on steroids Extreme ratio (e.g. 20:1) and fast attackExtreme ratio (e.g. 20:1) and fast attack Usually sets the highest possible peak signal levelUsually sets the highest possible peak signal level ““Brickwall” limiter – Digital limiter with infinite ratio and Brickwall” limiter – Digital limiter with infinite ratio and

attack speedattack speed

BombFactory BF76 (UREI 1176 emulation) –

No “Threshold” Control; set by Ratio and Input level

VU Meter can display gain reduction OR Output Level

DigiRack Compressor

All typical compressor controls, plus “knee” control

Separate meters for input level, output level and gain

reduction

Waves L2

Threshold automatically controls makeup gain

Brickwall Limiter – set for infinite ratio

Meters for input w/gain, gain reduction and output

Controls for dither

Snare pk= -15.2 dBFS

Snare w/gatepk= -16.1 dBFS

Snare w/ gate and compressorpk= -17.1 dBFS

Side chainingSide chaining

A side chain allows the level of one signal A side chain allows the level of one signal to control the level of anotherto control the level of another The input of the control signal is sent to the The input of the control signal is sent to the

Key InputKey Input of the dynamics processor of the dynamics processor The signal to be controlled is attached to the The signal to be controlled is attached to the

regular inputregular input Can be used for “ducking” or gatingCan be used for “ducking” or gating