SotF

Overview

SotF is a free, open-source audio player and optimizer for listeners who want to shape sound across headphones, speakers, or a room. It suits people prepared to configure audio processing; room correction demands measurement equipment, though speaker EQ does not. Its breadth across playback, correction, and plugin routing makes it more than a basic equalizer.

It plays FLAC, MP3, AAC, ALAC, and Vorbis files, and runs on Linux, macOS, and Windows. SotF says processing stays on the user's machine: it does not upload music or listening history, and it uses no analytics, telemetry, cookies, or tracking. Speaker EQ does query the public Spinorama API for a searched speaker model.

For more options in this category, see Audio Equalizer Software.

Key features

Room and headphone correction

Room EQ analyzes a room's response and calculates filters for a plugin chain. This gives listeners a route to room-specific correction, but requires connected speakers, a measurement microphone, and its calibration file. It is not a complete room-correction setup on software alone.

Headphone EQ calculates parametric filters targeting the Harman curve and supports hundreds of measured headphone models. That makes it a more accessible correction option for headphone listeners who do not have room-measurement gear.

Speaker EQ and plugins

Spinorama EQ offers correction for thousands of speakers from spinorama.org without a microphone. For supported speaker models, it is a practical way to try speaker correction without the equipment burden of Room EQ.

The product page lists more than 40 plugins, spanning EQ, compression, limiting, upmixing, binaural processing, convolution, and denoising. SotF also supports audio export for CamillaDSP, Equalizer APO, EasyEffects, Wavelet, PipeWire, and Roon, giving users options to carry correction into other audio setups.

Playback and system audio

On macOS, a CoreAudio HAL virtual device can route audio from all apps through a configured SotF plugin chain. This is useful for listeners who want system-wide processing rather than correction limited to SotF playback. The feature is specifically described for macOS.

Pricing

SotF has one plan: Free. It is open source under GPL-3.0, with no subscription. There is no paid tier or trial to weigh against it, so the main cost to consider is the equipment needed for room correction.

The free plan includes the player and correction tools; room correction still requires a measurement microphone and calibration file. Readers who want speaker correction without a microphone can use Spinorama EQ instead.

Platforms

SotF has releases for Linux, macOS, and Windows, covering desktop users across the three major platforms. Stable desktop releases are offered through platform stores, while beta or command-line builds are available through GitHub Releases.

Who it's for

SotF is a strong fit for listeners who want a free local audio player alongside flexible correction tools, particularly headphone owners and people with supported speakers. It is also suited to users who want system-wide processing on macOS or need to export audio settings to supported software.

It is less suitable for someone seeking room correction without buying or already owning measurement equipment, or for a listener who wants a simple playback app without configuring processing. Users can submit feedback or bug reports through GitHub and join the AudioScienceReview discussion linked from the product page.

Pros and cons

• Pros: Free, open-source software with no subscription, combining playback, parametric headphone EQ, speaker correction, and more than 40 plugins.
• Pros: Spinorama EQ works without a microphone, while headphone EQ supports hundreds of measured models.
• Pros: Local processing and no user-data collection or tracking support privacy-conscious listeners.
• Cons: Room EQ requires a measurement microphone and calibration file in addition to connected speakers.
• Cons: System-wide routing through a virtual device is described for macOS, so that particular workflow does not extend across all platforms.

Alternatives

Choose Nahimic if you want a free option spanning Android, iOS, macOS, and Windows; its download page lists compatible computers and versions, and it requires an audio driver update first.

Buddi is another free, GPLv2 app for Linux, macOS, and Windows, but it is budgeting software rather than an audio tool.

DeskFX Audio Enhancer is a freemium alternative for macOS and Windows.

For Linux audio processing, JamesDSP is free and has a PipeWire package.

EQBase is a freemium option for macOS; its free plan has no time limit.

EqLume is a free Mac app, with a Mac App Store version for macOS 26.0 or later on Apple silicon.

eqMac is a freemium macOS option whose free tier excludes Pro features.

Equaliser is a free-for-ever macOS alternative with no ads, tracking, or subscriptions.

Verdict

Choose SotF if you want a no-subscription player with substantial correction and plugin options, and especially if you value local processing or microphone-free speaker EQ. Look elsewhere if room correction is your priority but you do not have measurement equipment, or if you want an uncomplicated player rather than a configurable audio toolkit.