Softube’s Saturation Knob is a free plug-in that adds distortion with a single knob. You can choose from three modes that distort differently.
A saturation plug-in adds a faint distortion, as if the sound had passed through analog gear, to add thickness and warmth.
In this article we compare Saturation Knob with 12 saturation plug-ins and rate how well it serves its purpose on three criteria. The basis is official manufacturer information.
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Score 2.0 / 5 (average of the 12 products compared: 3.0)
- Price
- Free
- Specs last checked
- 2026/09/25
- Range of texture
- 3 modes
- Per-band processing
- None
- Mix and tone control
- One knob
- Price (store, date)
- Not listed
Image: from the Softube official website (product image)
Summary
Among the 12 saturation plug-ins, Saturation Knob is rank C. The ranks run S, A, B and C, and C is the lowest. Averaging the scores for each criterion (out of 5, with the one criterion that matters most for the purpose counted double) gives 2.0.
Things to keep in mind
- Per-band processing (1 points): it has no function for changing the distortion by pitch range.
- Mix and tone control (1 points): control of the mix and the tone is limited.
Who it suits: people who want to try the effect of saturation (a faint distortion, as if passed through analog gear) for free first.
Main features of Saturation Knob
Free saturation with one knob
Saturation Knob is a free Softube plug-in in which one knob decides the amount of distortion. Uses such as thickening a bass, adding harmonics and shine to a vocal, and distorting a drum loop heavily are introduced. With so few controls, it suits trying saturation for the first time.
Three modes: Keep High, Neutral and Keep Low
The mode changes which band is left undistorted. Keep Low lets you distort a loop without disturbing the low end of the kick drum, and Keep High lets you distort the low bands while keeping the hi-hats. Together with the third, Neutral, you can choose from three kinds of distortion.
Three versions are included
When you get it for free, besides the ordinary plug-in for your DAW you also get versions for Softube’s Modular and Amp Room. Modular is Softube software for building sounds by connecting modules on screen, and Saturation Knob can be used inside it. It is also included in the paid Flow Mixing Suite and Flow Complete Suite.
Video: “Saturation Knob Walkthrough – Softube” (official SoftubeStudios YouTube channel; narration in English) Watch on YouTube
Where it is useful
- Adding a little to a bass for a thickness that is audible on small speakers
- Using Keep Low to distort a drum loop while keeping its low end
- Applying it lightly to a vocal to add brightness with harmonics
Rating by criterion
Range of texture: 3 / 5
We check the range of distortion types you can choose, from subtle warmth to strong distortion.
There are three modes that distort differently.
Per-band processing: 1 / 5
We check whether the distortion can differ for low and high pitches.
It has no per-band processing.
If “per-band processing” matters most to you, Saturn 2 (5 points) is a better fit.
Mix and tone control: 1 / 5
We check whether you can adjust how much is mixed with the original sound, and the tone.
The only knob is the amount of distortion; there is no mix with the original sound or tone knob.
If “mix and tone control” matters most to you, Saturn 2 (5 points) is a better fit.
How we score (Saturation plug-ins)
| Criterion | Basis | 5 pt | 4 pt | 3 pt | 2 pt | 1 pt |
|---|---|---|---|---|---|---|
| Range of texture | The range of distortion types you can choose, from subtle to strong | Choose from 20 or more kinds of distortion | Choose from 5 or more kinds of distortion | 2 to 4 kinds | 1 kind | — |
| Per-band processing | Whether the distortion can differ for lows and highs | Multiband processing of up to 6 bands | 2 to 3 bands | — | — | No per-band processing |
| Mix and tone control | Control of how much is mixed with the original sound, and of the tone | Mix, tone, dynamics and more can be adjusted for each band | Both mix and tone are available | One of the two | — | Not mentioned on the official page |
Each criterion is scored from 1 to 5 on how well the product serves one goal: adding thickness and presence to vocals and backing tracks. Scores follow the conditions in the table above, and the rank is based on an average in which "Range of texture" counts double. The basis is official manufacturer information. Sound quality and CPU load are not measured, so they are not scored; reviews from trade magazines are introduced in the articles for reference. Price is not part of the score. Features that cannot be confirmed from the manufacturer's or a retailer's description are scored as if absent. The "OBS (streaming)" column in the table shows whether the official page lists the VST2 format that the streaming software OBS Studio can use (○). OBS does not support the VST3 format. It is not part of the score.
Saturation Knob screens and images
Image: from the Softube official website (product image)
Saturation Knob system requirements and getting started
| Operating system | Windows 10 (64-bit) and 11 / Mac (macOS 14 or later) |
|---|---|
| Plug-in formats | AU, VST, VST3, AAX |
| Other | A Softube account and an iLok account are required |
| Free version | Free |
| OBS (streaming) | Works as it is (VST2 is listed) |
Checked on the manufacturer’s official pages on September 27, 2026. How to use plug-ins in the OBS streaming software is explained in How to use VST3 plug-ins in OBS.
Compared with other saturation plug-ins
Click a heading to sort. On a phone, the table scrolls sideways.
| Product | RankAvg. score | Range of texture | Per-band processing | Mix and tone control | Free | OBS (streaming) | Price (store, date) |
|---|---|---|---|---|---|---|---|
| FabFilterSaturn 2 | S 5.0 | 28 types | Up to 6 bands | Adjust per band | — | ○ | $149 [PB, checked Oct 26] |
| SoundtoysDecapitator | B 3.3 | 5 types | None | Mix + tone | — | ○ | $199 [PB, checked Oct 26] |
| MeldaProductionMSaturator | C 2.0 | Tube-style + harmonics | None | Dry/Wet + harmonics | Free | ○ | Not listed |
| SoundtoysRadiator | C 2.3 | One tube type | None | Mix + bass/treble | — | ○ | $99 [PB, checked Oct 26] |
| SoftubeSaturation Knob | C 2.0 | 3 modes | None | One knob | Free | ○ | Not listed |
| KlanghelmSDRR | B 3.3 | 4 modes x 2 models | None | Mix + RESPONSE | — | ○ | ≈$25.78 [Official, checked Oct 26] |
| KlanghelmIVGI | C 2.0 | 1 type | None | RESPONSE | Free | ○ | Not listed |
| OutputThermal | A 3.8 | 19 types | Band split | Tone, width | — | ○ | $149 [PB, checked Oct 26] |
| KazrogTrue Iron | B 3.0 | 6 transformers | None | Strength + mix | — | Not confirmed | $39.99 [Official, checked Oct 26] |
| iZotopeTrash | S 4.5 | 60+ types | 3 bands | Mix + Tilt + envelope | — | × (VST3 only) | $99 [Official, checked Oct 26] |
| Plugin Alliancebx_saturator V2 | B 2.8 | 1 type | 4 bands + M/S | Drive and mix per band | — | ○ | $100 [Official, checked Oct 26] |
| Plugin AllianceHG-2 | B 2.8 | 4 tube stages + switch | None | Mix + Air + Calibration | — | ○ | $125 [Official, checked Oct 26] |
Features checked on each manufacturer's official website on September 25, 2026. Check the store page behind the buy button for the price.
Read next
- MSaturator: features and rating (rank C)
- Radiator: features and rating (rank C)
- Saturn 2: features and rating (rank S)
- Decapitator: features and rating (rank B)
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