Dynamic EQ

Dynamics — Position 4

Dynamic EQ combines parametric EQ precision with dynamics reactivity. Each band operates as an envelope-follower-driven peaking filter — it only applies equalization when the sidechain level crosses the threshold, proportional to the overage and ratio. The result is EQ that responds to the music rather than being static.

Quick Start

For mix-bus de-muddying: enable Band 1 (200 Hz) in Compress Down mode, Threshold −18 dB, Ratio 3:1, Attack 15 ms, Release 120 ms. Leave Bands 2–4 at unity until you identify a specific problem frequency.

Modes

Mode	Behavior
Compress Down	Reduces gain at the EQ frequency when signal exceeds threshold — multiband compression
Expand Up	Increases gain when signal exceeds threshold — dynamic presence enhancement
Gate	Attenuates when signal falls below threshold — eliminates mud between hits

Spectral Analyzer

The GUI includes a real-time spectral overlay showing:

• Band tint fills — color-coded frequency regions per band
• Gain reduction meters — per-band GR in dB at the top of the spectrum
• Crossover lines — visual markers at 500 Hz, 2 kHz, and 6 kHz

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Per-Band Controls (×4)

Each of the four bands has identical controls:

Control	Range	Description
Enable	On/Off	Activates this band. Disabled bands pass signal unmodified.
Mode	Compress / Expand / Gate	Processing mode (see above).
Detector Freq	20 Hz – 20 kHz	Sidechain filter center. The envelope follower measures level at this frequency — can be set independently of the EQ band’s center.
EQ Freq	20 Hz – 20 kHz	Center frequency of the dynamic peaking filter applied to the signal.
Q	0.1 – 10.0	Filter bandwidth. Low Q = wider; high Q = surgical.
Threshold	−60 – 0 dBFS	Level at which processing begins. Below threshold: no EQ. Above: gain change proportional to ratio.
Ratio	1:1 – 20:1	Compression or expansion ratio. 2:1 is gentle; 4:1 assertive; 10:1+ approaches limiting.
Attack	0.1 – 200 ms	Envelope follower attack time. Fast (1–5 ms) catches transients; slow (20–100 ms) allows transients through.
Release	10 – 2000 ms	Recovery time. Too fast = pumping; too slow = over-damping. 80–300 ms is typical.
Makeup Gain	−12 – +12 dB	Static gain after dynamic processing.
Solo	On/Off	Routes only this band through a bandpass filter for monitoring.

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Techniques

Mastering De-Essing

Surgical sibilance control without affecting cymbal and instrument brightness between events:

Control	Band 3 or 4
Mode	Compress Down
Detector Freq	7000 – 8000 Hz
EQ Freq	7000 Hz
Q	1.5 – 2.0
Threshold	−14 to −10 dBFS
Ratio	2:1 – 3:1
Attack	3 – 8 ms
Release	50 – 100 ms

De-Essing vs. Static EQ

A high-shelf cut at 7 kHz permanently reduces all HF content. Dynamic EQ only attenuates during actual sibilant events — preserving the natural HF energy of cymbals, acoustic guitars, and consonants between sibilant moments.

Sub Control

Tame low-end peaks without flattening sub energy:

Control	Band 1
Mode	Compress Down
Detector Freq	60 – 80 Hz
EQ Freq	60 Hz
Q	1.0
Threshold	−18 dBFS
Ratio	3:1
Attack	5 ms
Release	120 ms

Mud Gate

Eliminate low-mid buildup between drum hits or guitar chords:

Control	Band 2
Mode	Gate
Detector Freq	200 – 250 Hz
EQ Freq	220 Hz
Threshold	−22 dBFS
Ratio	4:1

Dynamic Presence Enhancement

Increase upper-mid presence on transient peaks — when the bus gets loud, the targeted frequency range opens up, adding definition to the collective sound:

Control	Band 3
Mode	Expand Up
Detector Freq	2500 – 3500 Hz
EQ Freq	3000 Hz
Threshold	−24 dBFS
Ratio	2:1

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Implementation Notes

• Sidechain detection uses a +6 dB peaking filter at the detector frequency
• 0.05 dB gain hysteresis prevents redundant coefficient recomputation during stable envelope periods
• Gain reduction displayed via lock-free AtomicU32 per band, updated from audio thread with Relaxed ordering

See Also

• Techniques & Presets — Dynamic EQ applications (de-essing, sub control, mud gate)
• Genre Signal Chains — Dynamic EQ role per genre
• Instrument Buses — frequency-dependent control per bus