Dynamic Resonance Suppression Explained (and Soothe 2 Alternatives)
What a dynamic resonance suppressor does, how it differs from a de-esser, and what the free and cheaper alternatives to Soothe 2 can actually do.
A dynamic resonance suppressor scans the spectrum continuously and pulls down only the frequencies that jump out at that instant. Unlike a static EQ cut, which removes the same band all the time, it acts only when a resonance actually appears. Soothe 2 is the best known example. This guide explains how the process works, when you need one, and what the free and cheaper options actually do.
Disclosure: we make audio plugins. One free plugin of ours appears below, clearly labeled, and it is a de-esser rather than a resonance suppressor. The difference is explained in full. No affiliate links.
What a Dynamic Resonance Suppressor Does
Take a vocal recorded in an untreated room. It probably has a build-up around 250 Hz from the desk, a nasal peak near 1 kHz, and a harsh spot somewhere between 3 kHz and 5 kHz that only appears on certain words. A static EQ can cut all three, but those cuts stay in place for the whole take. On the words where the problem is not present, you have removed tone for no reason.
A dynamic resonance suppressor splits the spectrum into a large number of narrow bands, measures each one against a moving average of its neighbours, and applies gain reduction only where a band sticks out. When the resonance stops, the reduction stops. The result is a vocal that keeps its character but loses the moments where a specific frequency rings.
The important word is relative. These tools do not look for an absolute level. They look for a band that is louder than the spectral curve around it, which is why one setting can work across very different material.
How It Differs From the Tools You Already Have
| Tool | What it reacts to | Where it acts | Best at |
|---|---|---|---|
| Static EQ | Nothing, it is always on | Fixed bands you choose | Consistent problems: rumble, a room mode |
| Compressor | Overall level | The whole signal | Dynamic range, not tone |
| Multiband compressor | Level within 3 to 5 bands | Wide fixed bands | Broad tonal balance over time |
| De-esser | Level in the sibilant range | One band, usually 4 to 9 kHz | Sibilance specifically |
| Dynamic resonance suppressor | A band standing proud of its neighbours | Many narrow bands, anywhere | Ringing, harshness, nasal peaks |
The distinction that matters most in practice is the last two rows. A de-esser is a specialist working in a known frequency range on a known problem. A resonance suppressor is a generalist hunting anywhere in the spectrum. They are not substitutes for each other, and the marketing around this category often blurs that.
When You Actually Need One
Reach for dynamic resonance suppression when the problem moves. Specifically:
- Harshness that comes and goes. Certain vowels ring in a way others do not, so a static cut is either too much or too little.
- An untreated recording space. Room modes excite different frequencies depending on the note being sung.
- Bright condenser microphones on a loud vocalist. The upper mids spike on the pushed lines and behave on the quiet ones.
- Acoustic guitar and strings, where body resonances jump on specific notes.
- Cleaning a sample before it goes into a beat, where you cannot re-record the source.
Do not reach for one when the problem is constant. A permanent 300 Hz build-up is an EQ cut. Using a dynamic tool for a static problem costs CPU and adds latency for no benefit.
Soothe 2 Alternatives, Honestly Assessed
Soothe 2 by oeksound is the reference in this category, and it is priced accordingly. The realistic alternatives fall into three groups.
Other paid dedicated tools. A handful of developers now make broadband dynamic suppressors, and several DAW makers have added dynamic EQ bands that approximate the behaviour. These get closest to the original.
Dynamic EQ, which you may already own. Most modern EQs offer dynamic bands. The difference is manual work: you find each resonance yourself and set a band on it, where a dedicated suppressor finds them for you. For two or three problem frequencies, dynamic EQ does the job. For a spectrum full of them, the manual approach stops being practical.
Multiband compression. The oldest approach and the bluntest. Three to five wide bands cannot isolate a narrow ring, so you end up ducking a lot of material you wanted to keep. It works for broad harshness and not much else.
An honest summary: there is no free plugin that convincingly replaces a good broadband suppressor. What there is, and what most people actually need, is a good de-esser plus two or three well-placed dynamic EQ bands. That combination covers the majority of vocal problems at no cost.
Settings That Work as a Starting Point
Whatever tool you use, the same principles apply.
- Work in context, not solo. Resonances that scream in isolation are often masked in the mix. Setting these tools soloed leads to over-processing every time.
- Start with the depth too high, then back off. Push the reduction until you can clearly hear the plugin working and the vocal starts to sound dull, then reduce until the dullness goes and the ring stays gone.
- Use the difference or delta listening mode. Most of these tools let you hear only what is being removed. You should hear ringing and harshness. If you hear words and melody, the settings are too aggressive. This is the same honesty check a good de-esser gives you.
- Limit the working range. There is rarely a reason to let the processor act below 200 Hz on a vocal. Constraining the range prevents it chewing the fundamental.
- Watch the latency. These plugins often use lookahead and linear-phase filtering, which can add meaningful delay. Fine while mixing, awkward while tracking.
Sound On Sound has published extensively on spectral processing, and iZotope maintains accessible explainers on dynamic EQ behaviour.
Where It Goes in the Chain
Corrective processing goes early, before anything that reacts to level or adds harmonics. A workable rap vocal order:
- Subtractive EQ for the constant problems
- Dynamic resonance suppression for the moving ones
- De-esser
- Compression
- Saturation
- Tonal EQ, then sends
Suppression before compression matters for the same reason de-essing does: a compressor reads a resonant peak as loudness and turns the whole word down, so you hear a dip on the vowel behind the problem. Remove the trigger first. There is a fuller treatment in our vocal chain guide, and a companion piece on what saturation does further down the chain.
Finding a Resonance By Ear, Without Any Special Plugin
Before reaching for a dedicated tool, it is worth being able to locate a resonance yourself. The technique is old and takes about a minute.
- Put a parametric EQ on the track and make a narrow band with a high Q, around 8 to 10.
- Boost that band by 10 to 12 dB. It will sound awful, which is the point.
- Sweep it slowly across the range you suspect. On a vocal, start between 200 Hz and 6 kHz.
- The frequency where the boost turns painful rather than merely loud is the resonance.
- Now invert the boost into a cut, and reduce the Q until the cut sounds natural. Usually 2 to 4 dB is enough.
Two cautions. Sweeping with a large boost fatigues your ears quickly, so work in short passes. And a boost makes everything sound like a problem, so confirm the frequency by cutting it and checking that the track improves, rather than trusting the boost alone.
If the cut is only needed on some words, that is the signal you want a dynamic band rather than a static one. If it improves the whole take, a static cut is simpler, cheaper in CPU, and adds no latency. The Audio Engineering Society publishes peer-reviewed research on perceptual audio processing for anyone wanting the underlying science.
Six Mistakes Worth Avoiding
- Using it instead of fixing the source. Moving the microphone six inches or hanging a duvet behind the vocalist solves more than any plugin.
- Setting it soloed. Guarantees over-processing.
- Running it across the whole spectrum on a vocal. Constrain the range so it leaves the fundamental alone.
- Stacking it with heavy de-essing. Both tools will target the same sibilant peak and you will get a lisp.
- Using it on a full mix as a fix. On a master it can work gently, but harshness in a mix usually comes from one element that should be treated on its own channel.
- Ignoring the CPU and latency cost. Many narrow bands with lookahead is expensive. Print the result if the session gets heavy.
Stock and Free Options by DAW
| DAW | Closest stock tool | What it can and cannot do |
|---|---|---|
| FL Studio | Fruity Parametric EQ 2, Maximus | Maximus offers multiband dynamics; narrow automatic suppression is not available |
| Ableton Live | EQ Eight, Multiband Dynamics | Multiband Dynamics handles broad ranges; no per-band automatic detection |
| Logic Pro | Channel EQ, Multipressor, Vintage EQ | Multipressor covers four bands, enough for broad harshness |
| Pro Tools | Dyn3, EQ3 7-band | Manual dynamic bands only |
| Reaper | ReaEQ, ReaXcomp | ReaXcomp supports many bands, so it gets closer than most stock tools |
| Studio One | Pro EQ3 with dynamic bands | Dynamic bands are built in, which covers targeted resonances well |
From Our Own Line
To be precise about what our tool is: VEIL is a de-esser, not a broadband resonance suppressor. It works in the sibilant range with a split-band design, so the body of the voice is never touched, and its detection is level-independent so one setting covers whispers and shouts. It also has a Removed listen mode that plays only what it takes away, which is the same honesty check described above.
If your problem is sibilance, VEIL handles it and costs nothing. If your problem is a nasal ring at 1 kHz that appears on some words, you want dynamic EQ or a dedicated suppressor instead. Using the wrong tool for the job is the most common reason people conclude that de-essing "makes vocals sound dull".
VEIL is free, keyless, with no account required, VST3 on macOS and Windows and Audio Unit on macOS.
Frequently Asked Questions
What is a dynamic resonance suppressor?
A processor that splits the spectrum into many narrow bands and reduces only the bands that stand out from their neighbours at that moment. Unlike static EQ it acts only when a resonance appears, so it removes ringing without permanently removing tone.
Is there a free alternative to Soothe 2?
No free plugin convincingly replaces a good broadband suppressor. The practical free approach is a de-esser for sibilance plus two or three dynamic EQ bands placed on the specific resonances you can hear, which covers most vocal problems.
What is the difference between a de-esser and a resonance suppressor?
A de-esser is a specialist that works in a known sibilant range, usually 4 to 9 kHz, on a known problem. A resonance suppressor is a generalist that searches the whole spectrum for any band standing proud of its neighbours. They solve different problems and are not substitutes.
Where does resonance suppression go in a vocal chain?
Early, after subtractive EQ and before compression. A compressor reads a resonant peak as loudness and turns the whole word down, so removing the trigger first prevents an audible dip on the vowel behind it.
Can I use dynamic EQ instead?
Yes, for a small number of problems. The difference is manual work: you locate and set each band yourself. For two or three resonances that is quick. For a spectrum full of them the manual approach stops being practical.
Should I set it while soloing the vocal?
No. Resonances that sound severe in isolation are often masked in the mix, so setting these tools soloed leads to over-processing. Always judge in context.
