Bass booster online — hear the low end before you download it

Where bass actually lives

The bottom two octaves of music sit roughly between 40 Hz and 160 Hz. A kick drum's body is around 60–80 Hz, an electric bass root note between 40 and 100 Hz, and the sub-bass in electronic music can run below 40 Hz where you feel it more than hear it. Above about 250 Hz you are into the region that carries the warmth of male voices, guitars and piano left hand — boost there and things get thick and boxy rather than deep.

That is why this control is a shelf at 120 Hz rather than a volume knob. A shelf lifts everything below its corner frequency by the amount you ask for and leaves everything above it essentially alone, so a vocal sitting at 500 Hz to 4 kHz does not get dragged up with the kick drum. Turning the whole track up is not bass boost; it is just louder.

How much is too much

+12 dB is four times the amplitude in the low end, and it is more than most tracks want. A few honest guidelines from listening rather than theory:

• Light (+3 dB) is what a thin-sounding phone recording or a podcast voice usually needs. It reads as warmth, not as bass.
• Medium (+6 dB) suits most music being played back on small speakers, laptops and earbuds, which physically cannot reproduce much below 100 Hz and benefit from being handed more of it.
• High and Max (+9 to +12 dB) are for genuinely bass-light material, or for the deliberately over-the-top bass-boosted sound. Expect to lose some headroom — big low frequencies eat it fast.

Bass boost and clipping are close friends

Low frequencies carry most of the energy in a mix, so boosting them raises your peak level far more than boosting treble by the same number of decibels. Add +12 dB of bass to a track that was already near full scale and you will be clipping within seconds.

Two things save you here. The soft limiter, on by default, rounds those new peaks off smoothly instead of squaring them. And the analysis panel measures your headroom through the bass and EQ settings you have actually chosen, so it tells you the real ceiling rather than the untouched file's — when a big boost pushes you past full scale it says by how many decibels, and what volume brings you back. If you want the deepest possible bass with no compromise, pull the volume slider down first, then add the bass: you trade a little overall level for a much cleaner low end.

Bass boost versus a proper equalizer

The shelf is the fast answer. When you want more control, the five bands of the equalizer let you separate "deep" from "boomy": lift 60 Hz for weight and pull 230 Hz down to clear the mud that makes a track sound like it is playing through a wall.

Note that the Bass Boost preset is not that shape. It runs +10 dB at 60 Hz, +5 dB at 230 Hz, −2 dB at 910 Hz, 0 at 3 kHz and +1 at 14 kHz — so it adds warmth at 230 Hz rather than removing it, and the −2 dB cut sits higher up to stop the midrange going honky under all that low end. It is a good starting point; for deep-without-boom, load it and then drag 230 Hz back to 0 or −3.

What your speakers can and cannot do

No amount of processing creates bass a driver cannot move. A phone speaker rolls off steeply below about 500 Hz; a laptop is not much better. Boosting 60 Hz on those does very little except waste headroom and, at extreme settings, make the speaker rattle. On headphones, in-ears, a decent Bluetooth speaker or a car system, the same boost is immediately obvious. If you are testing your settings, test them on the thing you will actually listen on.