Harmonic Multiband Compressor: the manual

The Harmonic Multiband Compressor is a six-band multiband compressor built around the Harmonics Engine, a dual-stage saturation system wired into the signal path. The engine can drive the detectors, saturate the bands audibly, or excite the summed mix, so the saturator-into-compressor chain engineers build from separate plugins lives in one insert. Under it sits a six-band compressor on an allpass-compensated Linkwitz-Riley LR4 crossover tree that sums flat within half a dB.

This manual covers installation and licensing, a tour of the interface, four session recipes, and the reference tables.

Install and activate

The plugin ships as VST3, AU, and AAX for Windows 10 and later and for macOS on both Intel and Apple Silicon. Run the installer for your platform, then rescan plugins in your DAW if it does not pick the new formats up automatically.

The license panel and your machine code

Everything license-related happens in the plugin's license panel. It shows your machine code, which reads VTM1-XXXX-XXXX-XXXX-XXXX, and the TRY button copies it for you. That code identifies the computer, and licenses are bound to it.

Free 14-day trial

Trials are full function for 14 days. Request one at /license/trial on the Vitric site: pick the plugin, paste the machine code from the license panel, enter your email, and the trial license arrives by email, bound to that machine. One trial per product per studio. When the trial ends the plugin drops to demo mode: everything still works, with a short output mute every minute, so a session opened after expiry still plays and edits rather than going silent or refusing to load.

Activating a purchased license

Your license key arrives by email after purchase. Open the license panel, paste the key, and if the machine is online that is the whole job. Keep the email: your keys are your proof of purchase.

Each license includes 3 machine activations with self-service moves. The license portal at /license lists your activations and lets you deactivate a machine yourself, which frees the slot for another machine. No support ticket needed to move between a studio desktop and a laptop.

Offline machines

Studio computers that never touch the internet activate through the portal instead. On any online machine, open /license, enter your key and the machine code the plugin shows on the offline machine, and download the license file. Carry the file over and load it in the plugin's license panel.

Interface tour

The display

The top of the window is a live spectrum you mix on: a pre and post analyzer running a 4096-point FFT with a 4.5 dB per octave display tilt. Crossovers and thresholds are draggable directly on the spectrum, and each band draws a gain reduction curtain in its own hue, so you see where the compressor is working and by how much without reading meters.

The Harmonics Engine

The engine has two stages. Harmonics IN works per band, after the crossover split and before compression. IN DRIVE is a tanh soft clipper, 0 to 100 percent, with two modes:

• DET ONLY.The drive saturates only the sidechain feeding that band's detector. The rounded peaks make the compressor ignore micro-transients and squeeze the body of the sound, the way slower vintage optical and tube units behave, while the audio you hear stays completely clean.
• AUDIBLE. The drive hits the audio path itself, per band, before compression, so the compressor reacts to and squashes the saturated signal. Audible saturation runs at 2x or 4x oversampling to keep the top end free of aliasing, with the dry path delay-compensated so it stays time-aligned.

Harmonics OUT is the exciter, and it works on the summed mix. It isolates just the added harmonics, runs them through a dynamic low pass that stays open around 18 kHz at low drive for air and closes toward 2 kHz at high drive for warmth without fizz, then blends them back in. The COMP control auto-matches level as you drive, so louder never biases your judgement of the character.

The per-band compressor

Each of the six bands carries a full compressor: threshold, ratio, knee, attack, release, makeup, and a range control that caps the gain change per band from 0 to 60 dB. Each band switches between Down mode, normal downward compression, and Up mode, bounded upward compression. Detection per band is blendable between RMS and peak, and each band has its own sidechain high pass.

Global controls

• Lookahead. Up to 10 ms, with the latency reported to the host automatically so everything stays aligned.
• Mix. 0 to 200 percent, so parallel blends and over-processed pushes both live on one knob.
• A/B, Copy, Link All. Two full states with Copy between them, Link All for moving every band together, and undo and redo.

With oversampling and lookahead both off, the plugin runs at zero added latency. Engage either and the latency is reported to your DAW.

Workflows

Drum bus density

Insert on the drum bus and raise IN DRIVE in DET ONLY mode on the bands carrying the kit's body. The detector hears rounded peaks, so the compressor stops snapping at every transient and leans into the body of the kit instead: vintage-slow response with zero added distortion. Watch the gain reduction curtains to confirm the compression moved from transient grabs to steady density.

Bass that reads small

Flip the low bands to AUDIBLE and add drive. The saturation generates harmonics above the fundamental, the compressor then controls them with the signal, and the bass carries on phone speakers without wrecking the low end. Use 2x or 4x oversampling here, since low-band saturation is exactly where aliasing products would land in the midrange.

Mastering control

Use the multiband foundation to tighten a wandering low end. The crossovers sum flat within half a dB, verified at the crossover points themselves, so splitting the spectrum does not smear the master. Keep COMP engaged while auditioning any drive, so you judge character rather than level, and use A/B with Copy to compare settings honestly.

Air without EQ

A touch of OUT EXCITER at low drive works like a high-frequency exciter: the smart filter sits open near 18 kHz, so the isolated harmonics blend in behind the mix as air rather than as an EQ boost of what is already there.

Reference

FAQ

What is the Harmonics Engine?

A dual-stage saturation and excitation system integrated into the compressor's signal path. Harmonics IN saturates each band before compression, either the detector sidechain only or the audible signal. Harmonics OUT excites the summed mix through a smart-filtered exciter. It replaces the saturator plugins engineers chain around their compressors.

Why put saturation before a compressor?

Because the compressor hears it. Harmonics round the transient peaks the detector reacts to, so the compressor ignores micro-transients and squeezes the body of the sound, behaving like slower vintage optical and tube units. DET ONLY mode gives you exactly that response change with zero audible distortion.

Why do multiband compressors usually smear the sound?

Most split the spectrum serially, and each split adds phase shift that the other bands never receive. The bands then refuse to sum back to the original. This unit applies every split's allpass across the whole tree, so the bands recombine flat within half a dB.

Is it good for mastering?

Yes. The crossovers sum flat, the dry path is delay-compensated under oversampling, and COMP auto-matches loudness as you drive so you judge character, not level.

Does it add latency?

Only when per-band oversampling or lookahead is engaged, and that latency is reported to your DAW automatically so everything stays aligned. With both off it runs at zero added latency.

Support

Anything unclear, broken, or missing from this manual: write to support@vitricaudio.com. Every purchase carries a 30 day money back guarantee, so if the plugin does not earn its insert, ask within 30 days and get a refund. More technique articles live in the guides index.