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Questions
Including the awkward ones. If something here is not answered, email support@fluideq.com.
What is FluidEQ Plus, and what stays free?
Plus is an optional membership, $5 a month or $50 a year, that supports FluidEQ and opens the Plus tab: every visualizer in the gallery, the Studio for making your own, the desktop visualizer, Dynamic Lighting (beta) and a place on the leaderboard. Everything that was free stays free — both engines, the EQ, the DSP rack, the players and Karaoke — and FluidEQ keeps working offline and without an account.
Plus is joined inside the app, never on this site: sign in from Account in the actions menu and pay on Buy Me a Coffee in your browser with the same email, so FluidEQ can recognise it. The app never sees your card. You can cancel at any time, and Plus stays on until the end of the period you paid for. One account stays signed in on up to 5 computers at a time.
Which engine: the FluidEQ Engine or Equalizer APO?
The FluidEQ Engine, for most people. It is FluidEQ’s own audio engine and runs inside Windows’ audio service, after your sound card’s effects, so the maker’s panel keeps working, and the EQ and the whole DSP rack apply to everything you hear with no restart. Custom Equalizer APO commands, Peace and VST plugins do not run under it.
Equalizer APO is the classic engine, bundled with the installer: it runs custom commands, Peace and VST plugins, but it takes your sound card’s effect slot, so vendor panels can lose controls; its DSP rack works in Library playback only, and its setup asks Windows to restart. Setup asks which you want, and the actions menu switches between them at any time.
Do I need an account?
Not for FluidEQ itself. The EQ, both engines, the DSP rack, the Library, Karaoke, Online Media and Share Audio all work without one, offline. An account is for FluidEQ Plus: with a free one you can browse Visualizers, see every published scene’s picture and details, try FluidEQ’s free sample for 10 seconds and see the leaderboard. Posting in the Forum uses your GitHub sign-in instead.
Plus never receives your audio, your track names or your EQ. The leaderboard is off unless you join it, and nothing you make leaves your computer unless you export or publish it.
Windows warns about an unknown publisher
The installer is not code-signed yet, so Windows SmartScreen names no publisher and may stop it with a warning. Check that the app is FluidEQ, then choose More info → Run anyway. The download dialog walks through both clicks and shows the installer’s SHA-256, so you can check the file you got.
What is signed is every update: from 1.7.0, FluidEQ installs an update only when it carries the maker’s signature. A copy you compile yourself is unsigned for Windows too, and warns the same way.
USB DACs, Bluetooth, several outputs at once?
Anything Windows exposes as an output endpoint. Each output keeps its own tuning, and a second output can play at the same time with its own EQ and profile. Under the FluidEQ Engine, an output the engine is not on yet offers Enable, and the one you are listening on is enabled for you. Under Equalizer APO, Bluetooth devices work as long as APO is attached to them during its setup — some Bluetooth stacks present the endpoint only while the device is connected, so pair first. Remote Desktop audio is the one output no EQ can reach.
Will it slow down my PC or add latency?
Parametric filtering costs very little. What you can measure comes from convolution, and from linear phase if you choose it under the FluidEQ Engine — about 350 ms of delay for each active EQ group. There is no virtual audio device and no kernel driver in the path, and Processes in the app names every part of FluidEQ, the engine inside Windows included, with an honest CPU and memory total.
Your EQ applies while FluidEQ is running: closing the window keeps it on from the tray, and quitting from the tray takes the EQ and the rack off every output.
How do I get the source code?
From the same place as the binary, which is what the GPL requires. The whole repository is at github.com/StartSWest/FluidEQ, and the corresponding source for this exact release is linked in the footer below, alongside the source for the copy of Equalizer APO that the installer bundles.
Nothing restricts what you may do with it. Use it, study it, change it, give it away — those come with the licence, and a Plus membership changes none of them.
Does Karaoke remove the vocals from a song?
The Karaoke tab does not, and the Karaoke Maker does — which is worth separating before you buy. Karaoke plays the audio file you give it and lines timed lyrics up against it. It does not strip a vocal out of that file, change its key or change its tempo: what you hand it is what you sing over.
What it does instead is the part around the music: LRC, eLRC and UltraStar lyrics timed to the track by word or syllable, a pitch lane comparing your voice against the song’s real notes when the file carries them, a melody guide tone, guitar chords estimated from the backing track, and a review that points at the bars you drifted on and counts you back in. There is no score, no account and no library, and the Karaoke tab itself makes no network call at all.
The Maker is where a song becomes singable. Since 1.4 it can split a track into voice and backing on your own machine and keep both with the draft, each with its own level — so the instrumental can come out of the song rather than being found somewhere. Around that: the words transcribed off the recording or pasted in and kept, the timing tapped by ear, the melody read off the track. Transcribing is the one thing that fetches anything — a speech model, downloaded on your press the first time. Separation, timing and melody all run here.