Bass Booster — Add Deep Bass to a Song, Online Free

What the bass control actually turns up

This is a low-shelf filter. It raises frequencies below 150 Hz by the amount you set, up to +15 dB. Mids and highs stay where they were. It is not a volume knob.

A shelf can only amplify bass the file already has. A phone recording of a voice has very little energy under 80 Hz, so a big boost will not produce a sub drop. Judge the result on headphones or real speakers. A phone speaker cannot play that range, so a heavy boost can sound like nothing, or like mud.

How much bass to add

The useful range is small. Past it, you are making an effect.

• +3 to +6 dB: thin voice memos, interviews, and tracks that are all midrange.
• +6 to +9 dB: drums and bass that need to sit forward. Check that voices still cut through.
• +9 to +15 dB: a deliberate low-end effect. Speech often becomes hard to follow here.
• If the low end crackles, the shelf has run out of headroom. Back the slider off.

Bass boost, volume boost, and the equalizer

Pick the page that matches the problem.

• Bass booster, this page: only the low end under 150 Hz. The file sounds thin, not quiet.
• Volume booster: the whole file, up to 4×, with a limiter. The file is quiet at every frequency.
• Equalizer: lows, mids, and highs as separate shelves. Use it when 150 Hz is the wrong cutoff.

Where a bass boost goes wrong

Heavy bass hides speech. Preview at a normal listening level, not with the speakers already turned down, or you will save something that booms in a car and buries the voice.

Export WAV if you will keep editing. MP3 at 320 kbps is the right choice when the file is finished. The filter does not resample or change pitch. If the boost would push peaks over full scale, a limiter softens those peaks so the export does not hard-clip.