Dynamics Processors Riding the wave

What are dynamics? “In music, dynamics normally refers to the volume of a sound or note” - Volume: “the softness or loudness of sound” – Essential Dictionary of Music. Harnsberger, L.. Alfred Publishing Co., Inc “dynamic range is the difference between the quietest and loudest volume of an instrument, part or piece of music.” -

Peak vs. RMS A peak is the highest absolute level of a signal (“maximum”) RMS – Root Mean Square.707 of peak value.707 of peak value “average” level of a signal “average” level of a signal Your perception of volume usually corresponds to the average level of a signal as opposed to the peak level

Parts of musical sounds A instrument’s sound can be analyzed by how it behaves over time. Attack - the onset of the sound, sometimes called an attack transient Decay - after the initial transient, there is often a drop-off in the amount of energy in the sound. Sustain - After the energy from the attack is spent, the instrument may ring on for some time Release - the behavior of the instrument after the note is no longer being held by the musician These terms are derived from synthesis

ADSR Envelope htp://

ADSR of a snare hit Attack Decay Sustain “Release”

Dynamics Processors Operate on the dynamic range of a signal Envelope generator – VCA Automatic volume control Two basic types Compressor (Limiter) – reduces dynamic range Compressor (Limiter) – reduces dynamic range Expander (Gate) – enlarges dynamic range Expander (Gate) – enlarges dynamic range

Typical Controls on a Dynamics Processor Threshold – the signal level at which the processor will begin to work Ratio – the amount of signal reduction as compared to the original signal level over the threshold Attack – the length of time the processor will take to apply (comp) or reduce (gate) gain reduction Release – the length of time the processor will take to give back (comp) or take back (gate) the gain Output – make up (or reduce) overall signal level

Expanders/Gates Expanders increase the dynamic range of a signal by reducing the level of the signal below the threshold Expanders and gates are often used for noise reduction and/or to reduce the amount of “bleed” on a channel (e.g. drum mic’s) Gate = automatic mute switch (sort of…)

Compressors/Limiters Compressors decrease the dynamic range of a signal by reducing the level of the signal above the threshold Compressors actually make things “softer” Compressors actually make things “softer” Compressors are often used make a signal louder By reducing peak signal level, it allows you to increase the average level by bringing up the overall gain By reducing peak signal level, it allows you to increase the average level by bringing up the overall gain Limiter = compressor on steroids Extreme ratio (e.g. 20:1) and fast attack Extreme ratio (e.g. 20:1) and fast attack Usually sets the highest possible peak signal level Usually sets the highest possible peak signal level “Brickwall” limiter – Digital limiter with infinite ratio and attack speed “Brickwall” limiter – Digital limiter with infinite ratio and attack 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= dBFS Snare w/gate pk= dBFS Snare w/ gate and compressor pk= dBFS

Side chaining A side chain allows the level of one signal to control the level of another The input of the control signal is sent to the Key Input of the dynamics processor The input of the control signal is sent to the Key Input of the dynamics processor The signal to be controlled is attached to the regular input The signal to be controlled is attached to the regular input Can be used for “ducking” or gating Can be used for “ducking” or gating