Docs

Quick start

1. Install the extension and sign in once with a free account.
2. Play a song in any tab (YouTube or anywhere with audio).
3. Click the Karafilt icon, or press Ctrl+Shift+K.
4. Pick a mode and set the Vocal Removal slider.
5. Click Start Filtering. Vocals drop out in real time.

The side panel is pinned to the tab you started it on. You can also right-click a page and choose “Filter this tab with Karafilt”.

Processing modes

Spectral

Frequency-selective center-channel cancellation (STFT). Removes the lead vocal while preserving bass and the stereo image. The balanced, recommended default.

Spectral Deep (Strong)

Everything Spectral does, but it nulls the center vocal more completely, widens the vocal band, and also thins panned backing vocals and stereo harmonies — a more vocal-free, thinner mix. Best for tracks with heavy backing vocals; instruments in the vocal range get a little thinner as a trade-off.

Basic

Simple center-channel subtraction with bass protection. Fastest and lightest; lower quality than the spectral modes.

The Vocal Removal slider sets how much of the detected vocal is removed (0% is clean passthrough, 100% is maximum). It applies to every mode.

What to expect

Every Karafilt mode works by cancelling the center channel of a stereo mix — the place where lead vocals usually sit. That makes it fast and private, but it also means results depend on how a song was mixed. Some songs come out near-instrumental; others barely change. We can't guarantee it works on everything.

Works best on

Standard studio stereo mixes with the lead vocal panned dead-center — which covers most pop, rock, hip-hop, and electronic releases from roughly the mid-70s onward.

Expect weaker results on

• Mono recordings or mono uploads — with no stereo separation there is nothing to cancel.
• Old hard-panned stereo (many 50s–60s records) where the voice sits in one speaker instead of the center.
• Live recordings and concert videos — the vocal bleeds into every microphone, plus crowd noise.
• Heavy vocal reverb or stereo delay — the dry voice drops out but its echoes are in the sides and stay audible.
• Wide double-tracked or backing vocals — try Spectral Deep, at the cost of a thinner mix.
• Sparse acoustic tracks — removing the voice from a voice-and-guitar recording leaves an obvious hole, and center-panned instruments (bass, kick, snare, solos) can dull slightly in any song.

Before you queue a song for a party, check its community star rating — it tells you how well the filter worked for other people — and use the Vocal Removal slider to find the sweet spot between removal and sound quality. Rating songs yourself helps everyone after you.

Karaoke lyrics

Synced lyrics

The side panel looks up time-synced lyrics (via LRCLib, with lyrics.ovh and Genius fallbacks) and highlights them line-by-line and word-by-word as the song plays. Falls back to plain lyrics when no timed version exists.

Where lyrics work

Karafilt identifies the song from the tab's media title, which works best on YouTube and similar sites where the title names the artist and track. On some players — Spotify and SoundCloud, for example — the track can't be identified reliably, so lyrics won't appear there even though vocal filtering still runs. And a song that isn't in the public lyrics databases yet (common for niche or brand-new releases) has nothing to show, or only a plain untimed version.

Focus mode & Sync

Focus shows three large lines at a time and swaps pages as the song moves. Sync keeps the active line and word in step with playback — turn it off to scroll and read manually.

Right-to-left support

Lyric lines auto-detect their direction, so Arabic, Hebrew, Persian, and Urdu render correctly right-to-left — per line, so mixed-language songs display each line correctly.

Wrong song? & refresh

If the match is off, open “Wrong song?” to pick from alternative matches, hit refresh to re-search, or use the Google search fallback when nothing fits.

Customizing the lyrics

Open Settings (the gear in the side panel) to tune how the lyrics look. Your choices are saved across sessions.

Font

Choose Default, Serif, Rounded, or Monospace.

Font size

Scale the lyrics from 80% up to 200% for easy reading.

Highlight color

Pick the color used for the active line and the currently-sung word.

Reset to defaults

Restore all appearance settings in one click.

Rate the filter

Tell us how well vocal removal worked on a song with a 1–5 star rating and an optional comment, tied to the song and the active mode. Revisit a song and the panel pre-fills your previous rating so you can update it.

Community ratings

The panel shows a song's average rating and how many people rated it. Only aggregate averages are shown — individual ratings stay private.

YouTube thumbnail badges

Rated videos get a ★ badge on their YouTube thumbnails so you can judge filter quality before opening them. (Hide with localStorage.kflNoBadges = "1".)

Your usage stats

While you're signed in, Karafilt records which songs you filter and for how long, so your account page can show your stats: total time filtered, sessions, unique songs, a per-mode breakdown, and your most-filtered and recently-filtered songs. No audio is recorded — only the song title and how long the filter was active.

Accounts & privacy

Karafilt is free, but you sign in once with a free account (Google or GitHub) to use the extension. All vocal removal happens locally in your browser — audio is never uploaded. You can delete your account and all associated data at any time from your account page.