Free online tool

Bass Booster Online

Boost the bass of any song in your browser with a low shelf from -6 to +12 dB. Avoid distortion, balance for phones or headphones, and export an MP3 for free.

Open the free editor: upload MP3, WAV, AAC, OGG or FLAC, adjust speed, reverb, bass, tone, width and space, then export MP3 or a ZIP of many tracks. Everything runs in your browser.

A bass booster adds weight to the low end of a track. Here it is a single low shelf filter with a range of -6 to +12 dB, applied at normal speed with everything else at zero. That is enough to make a thin phone rip feel full on headphones, to give a quiet acoustic recording some chest, or to push a rap beat toward the car-stereo sound. It is also enough to ruin a track if you push it carelessly, so this page spends as much time on how not to distort as on how to boost.

Everything runs in your browser. Load a file, leave Speed at 1.00x, raise Bass, listen, export an MP3. If you want bass boost as part of a slowed edit, the slowed reverb maker does that with the Haze Chamber preset at +12 dB. The control itself is documented on the bass control page, and because a bass boost nearly always wants a small high-end adjustment to go with it, the tone control page is worth a look too.

What the Bass control actually is

It is a low shelf. Below a corner frequency, everything is raised or lowered by the amount you set; above it, nothing changes. It is not a multiband equaliser, not a sub-harmonic synthesiser, not a dynamic bass enhancer. You cannot pick the frequency, change the slope or boost only the kick. One slider, one shelf.

That honesty matters because "bass booster" apps often claim to add bass that was not in the recording. A shelf cannot do that. If a track has no energy below 60 Hz, boosting the shelf raises the noise floor and the kick's upper harmonics, not a sub-bass that does not exist. What a shelf does well is rebalance: make a recording that is light on the bottom end sound the way it would on a system with a good woofer.

How much to boost

Speed is 1.00x and Reverb is 0% in every row. Preserve pitch does not apply.

Boosting without distortion

A low shelf adds gain. If the track is already mastered loud, which almost every modern release is, a +6 dB shelf pushes peaks over the ceiling and the result clips. Clipping on bass sounds like a crackle or a fuzzy edge on each kick, and once it is in the export it cannot be removed.

Three habits prevent it.

Boost in 2 dB steps and listen to the loudest section. Find the final chorus or the drop, not the intro. If a kick gets a hard, papery edge, you have gone too far. Back off one step.

Trade bass for tone. Perceived bass is relative. Cutting Tone by 1 to 3 dB makes the same bass boost sound bigger, because there is less high end to compare it against, and it does so without adding gain to the peaks. The lo-fi row above has +9 dB bass and -5 dB tone; the tone cut is doing half the work.

Respect the source. A track with a big, modern low end does not need +6 dB. It needs +2 dB or nothing. The boost is for recordings that are missing something, not for ones that already have it.

A real limiter would let you push harder safely. There is no limiter here. The range goes to +12 dB so that a very thin source can be rescued, not so that a finished master can be pushed that far.

Phone speakers versus headphones

A phone speaker reproduces almost nothing below about 200 Hz. Headphones and earbuds go down to 20 Hz or close to it. The same bass boost sounds like two different edits on the two devices.

On headphones, +4 to +6 dB is a satisfying, physical change. On a phone speaker the same boost does very little except, at higher settings, add distortion to the midrange when the small speaker is asked to reproduce energy it cannot. If your target is TikTok or Reels, where most playback is on phones, keep Bass at +2 to +4 dB and use a small Tone cut to make it feel heavier. If your target is a headphone audience or a YouTube listening video, go to +5 or +6.

The practical habit is to check both. Export, play the file on your phone's speaker at a normal volume, then on earbuds. If the phone version crackles, lower Bass by 2 dB and try again.

Bass and reverb

If you add reverb elsewhere on the site and also boost bass, the two compound. Reverb tails stack low frequencies, and a bass boost raises them further, which is the fastest path to mud. The rule on the slowed reverb maker page is to fix mud with Reverb first, then Bass. On a dry track at 1.00x there is no reverb to blame, so if the low end is muddy the shelf is simply too high.

Step by step

1. Load the track. MP3, WAV, AAC, OGG or FLAC. Bass boosting exposes low-bitrate artifacts less than slowing does, but a clean source still helps.
2. Click Dry. Speed 1.00x, nothing applied.
3. Skip to the loudest part of the song and start playback.
4. Raise Bass to +2 dB, listen, then +4 dB. Stop the moment you hear a hard edge on the kick.
5. Pull Tone down 1 or 2 dB if you want it heavier without adding gain.
6. Export and check on a phone speaker and on earbuds.

For a batch of tracks, Select All Tracks, set Bass once, and Download All for a ZIP. Save the setting with Create preset for next time.

Export and limits

The export is MP3 at 96 kbps and 32 kHz, encoded in a web worker in your browser. Low frequencies encode efficiently at that bitrate, so bass-heavy content survives well, and YouTube, TikTok and Shorts re-encode on upload anyway. There is no WAV export and no limiter. If you want a club-ready bass-heavy master, this is the sketch, and a DAW with a proper EQ and limiter is the finish.