AuxSpacer User Guide & Mixing Manual
Dynamic Spectral Frequency Carver & Resonance Tamer: master CARVE sidechain unmasking, TAME internal peak suppression, parametric Sensitivity EQ, and Zero Latency monitoring without volume pumping.
1. Overview & Signal Flow
Traditional sidechain compression ducks an entire audio track indiscriminately, creating unnatural breathing and pumping artifacts. AuxSpacer solves this by performing dynamic multi-band spectral carving: it analyzes incoming audio in real-time and carves micro-notches only at the exact frequencies where masking occurs, leaving the rest of the sound untouched.
2. Complete Knob & Parameter Reference
Every knob in AuxSpacer operates with high-precision 64-bit floating point DSP calculations. Below are the functional parameters, ranges, and auditory cues:
| Control Name | Parameter ID | Range & Unit | Default | Acoustic Function & Listening Tip |
|---|---|---|---|---|
| Depth | depth |
0.0% – 100.0% | 50.0% | Master Intensity. Center hero dial controlling the maximum depth of dynamic spectral attenuation across conflicting FFT bands (in CARVE mode) or resonant spikes (in TAME mode). At 25%–45%, transparently unmasks instruments; above 70%, aggressively ducks competing energy. |
| Detail | detail |
0.0% – 100.0% | 75.0% | Frequency Resolution / Q Tightness. Determines filter selectivity. Lower values apply smooth, broad musical carving. Higher values target laser-sharp surgical resonant peaks without touching adjacent harmonics. |
| Selectivity | selectivity |
0.0% – 100.0% | 60.0% | Detection Threshold Gate. Dictates how prominent an incoming peak must be before triggering carving or taming. High selectivity prevents low-level room ambience, headphone bleed, or quiet guitar resonance from triggering ducking. |
| Attack | attack_ms |
0.1 ms – 100.0 ms | 4.0 ms | Reaction Speed. How rapidly spectral carving or taming engages. Set fast (0.5–2 ms) for kick drum and snare attacks; set slower (10–25 ms) to let initial acoustic pick transients and vocal consonants breathe. |
| Release | release_ms |
1.0 ms – 1000.0 ms | 110.0 ms | Recovery Envelope. How quickly carved frequencies return to unity gain. Tune to track tempo: fast release (40–80 ms) for trap 808s; medium release (100–180 ms) for natural lead vocals. |
| Sensitivity EQ | sensitivity_eq |
20 Hz – 20 kHz | Interactive | Multi-Band Parametric Detector Filter. Shape the exact frequency spectrum triggering dynamic reduction. Supports High-Pass, Low-Pass, Bell, Notch, and Shelf filter bands with adjustable Freq, Gain, and Q. Includes per-band Bypass and Solo buttons to audition the isolated detector signal. |
| Learn (⚡ LEARN) | learn_profile |
One-Click Analysis | Off | Intelligent Frequency Profiler. Analyzes the incoming audio or sidechain in real time and automatically positions Sensitivity EQ nodes and Q bandwidths at dominant resonant or masking problem areas. |
| Stereo Mode | stereo_mode |
Stereo / Mid / Side | Stereo (Linked) | Spatial Routing. Choose whether processing applies across the entire stereo field, strictly in the phantom center (Mid channel for vocal separation), or on the wide stereo Sides (reverb/delay decrowding). |
| Dry/Wet | dry_wet |
0.0% – 100.0% | 100.0% | Parallel Blend. Blends unprocessed dry audio with carved/tamed audio. Ideal for dialling in subtle parallel pocketing on dense synth pad groups. |
| Output Gain | output_gain_db |
-18.0 dB – +18.0 dB | 0.0 dB | Makeup Trim. Clean post-processing gain stage. Use to level-match processed audio against bypassed audio for honest A/B evaluation. |
| Bypass & Delta | bypass / delta |
Toggle Buttons | Off | Diagnostic Audition. Bypass mutes all DSP. Delta inverts the processed signal against dry so you audition exclusively the frequencies being removed. |
| Zero Latency | zero_latency |
Toggle | Active | Zero Latency Mode. Eliminates buffer delays for live tracking, vocal recording, and low-latency tracking sessions. |
3. Operating Modes & Spatial Processing
Listens to an external audio signal (e.g., Lead Vocal or Kick Drum) fed into AuxSpacer's sidechain input. Instantly attenuates overlapping frequencies on the host track, making the lead element sit cleanly in the mix without volume drop.
Operates entirely internally without requiring an external sidechain track. Continuously tracks harsh stationary resonances, screechy vocal frequencies, or abrasive cymbal buildup, dynamically taming them only when they spike.
Stereo Channel Modes (Mid / Side Processing)
AuxSpacer provides three distinct stereo configurations to optimize spatial imaging:
- Stereo (Linked): Carves identical notches in both the Left and Right channels, guaranteeing complete stereo phase coherence.
- Mid Only: Carves spectral pockets exclusively in the center of the stereo field ($M = \frac{L + R}{2}$) while leaving the wide stereo sides untouched. Essential for keeping wide rhythm guitars and synth pads huge while opening a pocket for a mono center vocal.
- Side Only: Carves exclusively in the side channels ($S = \frac{L - R}{2}$), preserving center kick and bass punch while cleaning up stereo reverb and delay clutter.
Depth or raise Selectivity. You should only hear conflicting hash and resonant spikes.
4. Battle-Tested Mix Recommendations
When dense synths, pianos, and rhythm guitars compete with your lead vocal, place AuxSpacer as the final insert on your stereo Instrument Bus and route the Lead Vocal into the sidechain.
Acoustic Result: The vocal effortlessly floats forward in the phantom center, while the instrumental preserves maximum stereo width and warmth on the sides.
Eliminate low-end phase cancellation and mud between your kick drum transient and your sub-bass fundamental without volume pumping.
Acoustic Result: The kick drum snaps with instantaneous transient impact; the 808 note sustains cleanly with zero low-end flab.
Overhead microphones frequently capture shrill 3 kHz – 6 kHz cymbal wash and harsh cabinet reflections. Resonance Tame smooths these harsh peaks dynamically.
Acoustic Result: Shrill cymbal clatter is smoothed out, allowing you to boost high-end air on drum busses without inducing ear fatigue.
5. DAW Sidechain Routing Walkthrough
To use Sidechain Carve, your host DAW must route an auxiliary audio signal into AuxSpacer's sidechain input:
Ableton Live 11 / 12
1. Insert AuxSpacer (VST3) onto your Synth or Bass track.
2. In the device title bar, click the small triangle icon to reveal the sidechain panel.
3. Check the Sidechain toggle and select your source (e.g. Audio From: Lead Vocal).
4. In AuxSpacer, ensure the mode is set to Sidechain Carve.
Logic Pro 10.8 / 11
1. Insert AuxSpacer (Audio Unit) onto your channel strip.
2. At the top-right corner of the plugin window, open the Side Chain menu.
3. Select your sidechain track (e.g., Audio 1: Lead Vocal or Bus 3: Kick).
4. The meter will immediately show real-time spectral activity from the sidechain source.
FL Studio 21 / 24
1. In the FL Studio Mixer, select the sender track (Kick) and right-click the target track's send arrow (Bass) -> choose Sidechain to this track.
2. Open AuxSpacer on the target track.
3. Click the gear icon (Plugin Options) -> Processing tab -> map Aux Inputs to the sidechain track port.