soothe 2 alternatives in 2026
an honest comparison of every serious resonance suppressor on the market. what each does well, what it costs, and which one fits your workflow.
why this guide exists
oeksound released the original soothe in february 2016. it created a category that did not exist before: automated, full-spectrum resonance suppression. ten years later, soothe 2 remains the reference point every new tool is measured against.
but the landscape has changed. there are now a half-dozen serious alternatives at price points from free to $129, and three of them use techniques that were not available when soothe 2 was designed. this guide compares them honestly.
full disclosure: we make KERN SMOOTH, one of the tools compared here. we will give it the same honest treatment as everything else. if soothe 2 is better for your use case, we will say so.
what a resonance suppressor actually does
before comparing tools, it helps to understand the problem they solve.
every audio signal has resonant frequencies: peaks in the spectrum that ring longer or louder than the surrounding content. a vocal recorded in a boxy room. a snare drum with an annoying ring at 800 Hz. a synth pad with a harsh bite at 3 kHz.
a resonance suppressor detects these peaks in real time and reduces them dynamically. unlike a static EQ cut (which removes energy whether the resonance is active or not), a suppressor only acts when the frequency is actually problematic.
the result: you remove the harshness without removing the life.
how they work under the hood
most resonance suppressors use some form of spectral analysis (typically an FFT, or fast fourier transform) to decompose the audio into individual frequency bins. they compute a local spectral envelope, identify bins that protrude above it, and apply dynamic gain reduction to those bins specifically. the key engineering challenges are temporal smoothing (to avoid “musical noise” artifacts), frequency resolution (how precisely the tool can target a resonance), and preserving phase (to avoid comb filtering).
key takeaway
the fundamental difference between a resonance suppressor and a dynamic EQ: a dynamic EQ has 4-8 bands you place manually. a resonance suppressor analyzes hundreds or thousands of frequency points simultaneously and acts on all of them at once.
the contenders
here is every serious resonance suppressor available in 2026, organized by price tier.
premium tier ($129+)
oeksound soothe 2 – $219
the original and still the most recognized name. soothe 2 operates in the spectral domain with per-bin dynamic processing. it identifies resonances automatically and suppresses them with adjustable depth, sharpness, and selectivity.
what it does well: excellent preset library. two processing modes (hard for broadband, soft for surgical). external sidechain for spectral ducking. wide DAW compatibility including AAX. ten years of refinement.
where it falls short: $219 is steep for a single-purpose tool. requires an iLok account (no dongle needed, but still account-locked). CPU can spike to 3.2% at high quality settings. no psychoacoustic frequency weighting: it treats a 3 dB peak at 300 Hz the same as a 3 dB peak at 8 kHz, even though your ears hear them very differently.[^1]
best for: engineers who need the deepest feature set and do not mind the price. pro tools users who need AAX support.
baby audio smooth operator pro – $129 ($79 intro)
released april 2025, smooth operator pro is a significant upgrade from the original smooth operator. it adds per-node surgical control, sidechain mode for cross-track unmasking, stereo imaging controls, and linear phase processing.
what it does well: per-node “override global” controls let you set individual threshold and depth per frequency. 184 presets by grammy-winning engineers. clean UI. no iLok.
where it falls short: the “pro” price ($129 regular) puts it in soothe 2 territory. at the $79 intro price, it is competitive. no M/S processing mode separate from its stereo imaging. less established track record than soothe 2.
best for: producers who want surgical per-frequency control with a modern interface. plugin alliance subscribers.
sonible smart:EQ 4 – $129
smart:EQ 4 is primarily a tonal balancing tool, not a dedicated resonance suppressor. its AI analyzes audio content and builds custom EQ curves. the dynamic filter widget can suppress resonances, but it is a secondary feature.
what it does well: AI-assisted tonal balancing is genuinely useful. multi-track unmasking across up to 10 instances. genre-specific profiles. excellent for broad tonal shaping.
where it falls short: not designed for resonance suppression as a primary task. the dynamic EQ bands require manual setup for surgical resonance work. no full-spectrum automatic detection. at $129, you are paying for a general EQ with some dynamic capabilities, not a dedicated suppressor.
best for: engineers who need general intelligent EQ with some dynamic capability. not a soothe 2 replacement, but a complement.
mid tier ($50-$99)
tbproaudio DSEQ3 – €79 (~$87)
DSEQ3 is the most technically capable alternative to soothe 2. it operates entirely in the frequency domain with over 1,000 simultaneous dynamic filter bands. seven quality modes from eco to ultra.
what it does well: extremely precise frequency-domain processing. 12 independent pre-filter bands for shaping the detection curve. built-in loudness matching (AB-LM lite). no iLok. aggressive CPU optimization (up to 25% savings in v3). the closest thing to soothe 2 in terms of raw processing power.
where it falls short: the UI is functional but not inspiring. no psychoacoustic frequency weighting. documentation is dense. less polished than soothe 2 or smooth operator pro.
best for: technically-minded engineers who want maximum control and do not mind a steeper learning curve. the best value in the mid tier.
techivation M-clarity 2 – $129 ($64.50 on sale)
M-clarity 2 is an adaptive resonance processor with an AI mix assistant. it continuously analyzes audio and auto-adjusts its processing frequency range.
what it does well: adaptive frequency range that tracks the signal. AI mix assistant suggests settings. clean interface. v2 rewrote the dynamics engine (improved attack/release). no iLok.
where it falls short: regular price ($129) puts it in the premium tier despite less capability than soothe 2 or DSEQ3. frequently on deep sale, which makes the “real” price hard to gauge. less transparent about its processing architecture than competitors.
best for: producers who want AI-assisted resonance processing with minimal manual tweaking.
mastering the mix RESO – £49 (~$65)
RESO takes a different approach: instead of continuous suppression, it scans your audio and identifies specific resonant frequencies, presenting “targets” for you to resolve.
what it does well: the “calculate targets” workflow is intuitive for beginners. shows you exactly what frequencies are problematic. automatic Q optimization. simple, focused interface.
where it falls short: target-based workflow means it is more of a diagnostic tool than a continuous processor. less effective for dynamic content where resonances shift over time. does not suppress in real time across the full spectrum.
best for: producers who want to understand and learn about resonance problems, not just suppress them automatically.
waves curves equator – $79 ($39.99 intro)
waves’ entry into spectral suppression. “learn” mode analyzes audio and builds a personalized suppression curve. sidechain learning for cross-track unmasking.
what it does well: learn mode creates content-specific curves. sidechain unmasking. linear phase processing. 6 dynamic EQ bands. competitive intro pricing.
where it falls short: waves’ subscription/licensing history makes some producers hesitant. newer product with less track record. 6 bands is fewer than true full-spectrum suppressors.
best for: producers already in the waves ecosystem who want resonance suppression without leaving their existing toolchain.
budget tier (under $50)
KERN SMOOTH – $29
full disclosure: this is our plugin.
KERN SMOOTH uses 40 ERB (equivalent rectangular bandwidth) bands mapped to how humans actually hear.[^2] a resonance at 1 kHz and a resonance at 8 kHz receive different treatment because your ears perceive them differently. this psychoacoustic approach means the plugin can be more aggressive where it matters and more conservative where it does not.
what it does well: psychoacoustic frequency analysis using the ERB scale (40 bands). dual processing modes: resonance for sustained harshness, transient for percussive spikes. M/S routing for independent mid and side processing. real-time spectral display. under 3% CPU at 44.1 kHz. $29, no iLok, no subscription. permanent license.
where it falls short: newer product with a shorter track record than soothe 2 or DSEQ3. no AAX format (VST3 and AU only). no external sidechain input (yet). smaller preset library. maximum 5 knobs means less granular control than soothe 2’s parameter set.
best for: producers who want psychoacoustically-informed resonance suppression at an accessible price point. electronic music, indie, and hip-hop producers on ableton or logic.
why ERB bands matter
the human ear does not hear frequencies linearly. at 1 kHz, we can distinguish frequency differences of about 130 Hz. at 8 kHz, that resolution drops to about 960 Hz. the ERB scale, derived from Glasberg & Moore’s 1990 research on auditory filter shapes,[^2] models this variable resolution. a resonance suppressor that uses ERB bands naturally applies more sensitivity where your ears are most sensitive (1-4 kHz, the speech intelligibility range) and less where they are not.[^3]
hornet sleek – €29.99 (~$32)
a budget resonance suppressor with automatic detection and suppression. 4-band pre-process EQ shapes the detection window.
what it does well: genuinely affordable. automatic resonance detection. adjustable frequency window. “sleek factor” control is intuitive. no iLok.
where it falls short: less sophisticated processing than the mid-tier options. early versions had crackling issues with fast attack/release (fixed in v1.1.4). less transparent at high settings.
best for: producers on a tight budget who need basic resonance suppression.
free tier
TDR nova – free
TDR nova is not a resonance suppressor. it is a 4-band dynamic EQ. but it is free, it is excellent, and for many producers, it is the first tool they reach for when a mix sounds harsh.
what it does well: genuinely capable dynamic EQ with 4 bands plus HP/LP filters. multiple modes: parametric EQ, dynamic EQ, frequency-selective compression, multiband compression. spectrum analyzer. completely free, no strings.
where it falls short: 4 bands means you must identify problem frequencies manually. no automatic full-spectrum detection. no spectral analysis beyond the analyzer display. requires more skill and time than a dedicated suppressor. no AU format.
the paid upgrade (nova GE, ~$60) adds 6 bands, steeper filter slopes, frequency-dependent ratio, and upward compression. on sale as low as $14-19.
best for: everyone. seriously. if you do not own a resonance suppressor, start here. learn to identify problem frequencies manually. when you hit the limits of 4 bands, then consider a dedicated suppressor.
the comparison
| plugin | price | bands | CPU | psychoacoustic | modes | formats |
|---|---|---|---|---|---|---|
| oeksound soothe 2 | $219 | full spectrum | 0.2-3.2% | no | hard / soft | VST/VST3/AU/AAX |
| DSEQ3 | €79 | 1000+ | low-moderate | no | 7 quality modes | VST/VST3/AU/AAX |
| smooth operator pro | $79-129 | spectral nodes | moderate | no | linear phase opt. | VST/VST3/AU/AAX |
| KERN SMOOTH | $29 | 40 ERB | <3% | yes (ERB) | resonance / transient | VST3/AU |
| M-clarity 2 | $65-129 | adaptive | moderate | partial (AI) | adaptive | VST/VST3/AU/AAX |
| RESO | ~$65 | target-based | low | no | calculate targets | VST/VST3/AU/AAX |
| TDR Nova | free | 4 manual | very low | no | dynamic EQ | VST/VST3/AAX |
note
“psychoacoustic” in this table means the plugin uses a perceptually-weighted frequency scale (like ERB or Bark) for its analysis, not just raw linear FFT bins. this affects how the plugin weighs resonances at different frequencies relative to human hearing sensitivity.
how to choose
the right tool depends on three things: your budget, your workflow, and what you are actually trying to fix.
if you have a specific known problem (a room mode at 250 Hz, a harsh synth peak at 3.5 kHz): start with TDR nova. a dynamic EQ band placed precisely on the problem frequency is cleaner and cheaper than any suppressor.
if resonances shift and you cannot pin them down (a vocalist who moves around the mic, a live recording with variable room interaction): you need a full-spectrum suppressor. soothe 2, DSEQ3, or KERN SMOOTH will all handle this.
if you are working on the mix bus or in mastering: subtlety matters most. soothe 2’s “soft” mode and KERN SMOOTH’s resonance mode are both designed for transparent broadband work. DSEQ3 with conservative settings also works well here.
if you want to learn: RESO’s target-based approach teaches you what resonances look like. pair it with TDR nova to fix them manually. you will develop better ears than any automatic tool can give you.
if budget is the primary constraint: KERN SMOOTH at $29 or TDR nova (free) are the starting points.
key takeaway
there is no single “best” resonance suppressor. soothe 2 is excellent and established. DSEQ3 is the technical powerhouse. KERN SMOOTH brings psychoacoustic precision at an accessible price. TDR Nova is free and teaches you fundamentals. the best tool is the one that fits your workflow and budget.
the psychoacoustics behind the tools
most resonance suppressors treat all frequencies equally: a 3 dB peak at 500 Hz gets the same treatment as a 3 dB peak at 10 kHz. but your ears do not work that way.
the human auditory system resolves frequencies in bands that get wider as pitch increases. at 1 kHz, you can distinguish differences of about 130 Hz. at 8 kHz, that resolution drops to about 960 Hz. these bands are called ERB (equivalent rectangular bandwidth) bands.[^2]
this has practical consequences for resonance suppression:
- a resonance in the 2-5 kHz range (where speech formants live, where your ears are most sensitive) is far more noticeable than a resonance at 12 kHz
- suppressing a narrow resonance at 500 Hz requires more precision than suppressing one at 8 kHz, because your ears can resolve finer detail at lower frequencies
- a tool that treats all frequencies equally will either over-process the highs or under-process the critical midrange
this is why the ERB scale matters. it is not marketing: it is the perceptual science of how hearing works, derived from direct measurement of human auditory filters.[^2] [^3]
technical detail
the ERB formula: ERB(f) = 24.7 × (4.37 × f/1000 + 1). at 1 kHz, one ERB is 130 Hz wide. at 8 kHz, one ERB is 960 Hz wide. a 40-band ERB filterbank spanning 20 Hz to 22 kHz gives approximately 7× more frequency resolution in the critical midrange compared to a linear frequency scale. this is the same scale used in computational auditory models and hearing aid research.
what the academic research says
resonance suppression is not new in the academic literature. the core techniques have been published and refined over decades:
-
spectral envelope estimation: the foundation of any suppressor. identify the local spectral shape, then flag bins that protrude above it. Ephraim & Malah’s 1984 work on spectral subtraction for speech enhancement established the framework that every modern suppressor builds on.[^4]
-
temporal smoothing: the #1 cause of artifacts in naive implementations. without per-bin IIR smoothing, gain changes every ~23 ms in isolated frequency bins, creating audible metallic “musical noise.” the solution: independent attack/release smoothing per frequency bin, running at the STFT hop rate.[^4]
-
spectral reassignment: standard FFT has limited frequency resolution (~10.77 Hz per bin at 44.1 kHz with 4096-point FFT). spectral reassignment estimates the true instantaneous frequency of each component, allowing more precise targeting of resonances. first formalized by Auger & Flandrin in 1995.[^5]
-
magnitude-only processing: modifying only the magnitude while preserving the original phase avoids the comb filtering artifacts that plague naive implementations. this approach, formalized by Griffin & Lim in 1984,[^6] is now standard across all serious spectral processors.
the key insight from studying this literature: soothe 2 is not magic. it is carefully tuned classical DSP. the techniques it uses are well-understood and well-published. what differentiates tools in this category is not the underlying math, but the engineering decisions: which frequency scale to use, how to handle temporal smoothing, how to preserve transients, and how to keep CPU usage reasonable.
frequently asked questions
frequently asked questions
what is the best alternative to soothe 2?
it depends on your priorities. for psychoacoustic precision at a lower price, KERN SMOOTH uses 40 ERB bands mapped to human hearing. for a free option, TDR Nova is a capable dynamic EQ. for an all-in-one solution, Sonible smart:EQ 4 combines resonance control with AI-assisted EQ.
is soothe 2 worth the price in 2026?
soothe 2 is excellent software that defined the category. whether it is worth 7x the price of alternatives like KERN SMOOTH ($29) depends on your workflow. soothe 2 has a longer track record and more presets. newer options offer comparable or better results at a fraction of the cost.
what is a resonance suppressor?
a resonance suppressor automatically detects and reduces resonant frequencies in audio. unlike a static EQ that cuts the same frequencies constantly, a resonance suppressor only acts when a frequency becomes problematic, preserving the natural character of the sound.
can I use a dynamic EQ instead of a resonance suppressor?
yes, for simple problems. a dynamic EQ with 4-6 bands works well for known problem frequencies. but when resonances shift across the spectrum (like harsh vocals or ringing cymbals), a dedicated resonance suppressor with hundreds or thousands of frequency bands can address problems that a handful of dynamic EQ bands cannot.
what is the difference between a dynamic EQ and a resonance suppressor?
a dynamic EQ has a fixed number of bands (typically 4-8) that you place manually on problem frequencies. a resonance suppressor analyzes the entire spectrum simultaneously and applies dynamic gain reduction across hundreds or thousands of frequency points automatically. think of it as the difference between placing a few surgical cuts and having the plugin find every problem for you.
do resonance suppressors affect CPU performance?
yes, spectral processing is more CPU-intensive than standard EQ because it requires FFT analysis of every audio frame. soothe 2 uses 0.2-3.2% CPU depending on quality settings. DSEQ3 and KERN SMOOTH target under 3% at 44.1 kHz. running multiple instances on every channel is possible but worth monitoring.
references
a note from the developer
this guide is built on four years of studying psychoacoustics and DSP research. reading papers, building prototypes, making mistakes, and learning from all of it. i am a solo developer in copenhagen, and i am still learning every day.
if i got something wrong, missed a plugin that deserves to be here, or if you just want to share how you use these tools, i genuinely want to hear from you. reach out at jonas@kernaudio.io. every piece of feedback makes these guides better.
try it yourself
KERN SMOOTH: dynamic resonance suppression across 40 psychoacoustic bands. $29, no iLok, no subscription.