Control

Bass Control

Bass control is a low shelf from -6 to +12 dB. Learn why slowed edits need it, how headroom and clipping work, the phone check, and values that stay clean.

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.

Bass is the control that gives a slowed edit its weight. It is a low shelf filter with a range of -6 to +12 dB and a default of 0 dB. Push it up and everything below the shelf frequency gets louder; pull it down and the low end thins out. It is the same kind of filter as the bass knob on a car stereo, and the same filter behind the bass booster page, which is also why people underestimate it. Used well, it is the difference between a slowed track that feels heavy in the chest and one that just sounds slow. Used badly, it is the most common source of distortion in the slowed reverb maker. This page covers both.

What Bass does in signal terms

The editor applies a biquad low-shelf filter with its corner at 180 Hz. Frequencies well below 180 Hz get the full gain you set. Frequencies well above are untouched. Around the corner there is a gentle transition. At +6 dB the sub and kick region is roughly twice as loud in amplitude terms; at +12 dB it is about four times as loud.

The filter sits right after the speed change and before Tone, before the reverb split and before Width. That order has consequences. Whatever Bass does is fed into the reverb as well as the dry path, so a heavy boost produces a heavier, boomier reverb tail. The tone control handles the opposite end of the spectrum and the two together are the editor's entire EQ. There are no mid bands and no parametric EQ, so if a source has a problem in the 300 to 2000 Hz range, this editor cannot fix it.

Why slowed edits need bass

Three things happen when you slow a song, and all three push you toward adding low end.

Everything shifts down, including the kick. A kick drum tuned to 60 Hz at 1.00x is at 51 Hz at 0.85x and at 45 Hz at 0.75x. That is well below what phone speakers, laptops and small earbuds reproduce. The energy is still there, but fewer playback systems can show it. A low shelf lifts the whole region so the part that is still audible, from roughly 60 to 180 Hz, carries more of the weight.

Transients soften. Slowing stretches the attack of every hit, so the kick loses its click and the bass loses its pluck. The ear hears softer transients as less bass, even when the spectrum has not changed. A boost compensates.

The style expects it. Slowed + reverb grew out of chopped and screwed music, which was built around car audio and sub bass. Listeners expect a slowed edit to be heavy. A slowed track with a flat low end sounds like a mistake rather than a style. If your aim is to make a song slower and deeper, Bass is the "deeper" half.

Headroom and distortion

Here is the catch. Modern masters are already loud. Their peaks sit at or near full scale, and a lot of that peak energy is low frequency. Adding +12 dB below 180 Hz can push those peaks past full scale, and nothing in this editor stops that. There is no limiter in the chain. In the live preview the browser clips whatever exceeds the maximum, and in the export the samples are hard-clipped before MP3 encoding. The result is a crackle or a fuzz on every kick.

How to tell whether you are clipping:

• Switch to the Dry preset while the chorus plays. If the crackle disappears, the boost caused it.
• Listen on headphones at a moderate volume. Clipping sounds like a dry, papery edge on the kick, not like the kick itself getting louder.
• Watch the spectrum visualiser during playback. If the low bars slam against the top on every beat, you are at or over the limit.

The fix is to lower Bass until the crackle goes, then lower it one more step for safety. On most commercial masters that lands between +4 and +8 dB. The +12 dB in Haze Chamber is tuned for sources with room to spare and is a ceiling, not a target. Quieter masters, older recordings and your own unmastered mixes will take far more boost without complaint.

The reverb makes this worse. Boosted bass goes into the convolver, and the tail adds its own low-frequency energy on top of the dry signal. With a long Space and a high mix, the sum can clip even when the dry signal alone does not. If the tail rumbles, trim Bass before you trim Reverb.

The phone speaker check

Every slowed edit should be heard on a phone speaker before it is posted, and Bass is the main reason. Two opposite problems can show up:

1. The bass vanishes. Phone speakers roll off steeply below roughly 200 Hz. A boost centred at 180 Hz and below mostly lands in that dead zone, so the heavy edit you heard on headphones comes out thin. There is not much to do about physics, but a moderate boost of +4 to +6 dB tends to survive better than +12 dB because it adds energy in the upper bass the speaker can still reproduce without saturating.
2. The speaker distorts. Small drivers have very little excursion. Hammer them with a +12 dB low shelf and they buzz and flutter. That is the speaker clipping, not your file, but the listener does not know the difference.

Export a short test, send it to your phone, and listen at a normal volume. If it buzzes, pull Bass back by 3 dB and try again. Most creators settle on a house setting between +5 and +8 dB that works on both headphones and phones.

How Bass interacts with the other controls

Speed. Slower speeds move the low end further down and make a boost more necessary and more risky at the same time. At 0.75x even +6 dB can be plenty.

Tone. The two shelves tilt the spectrum from opposite ends. Heavy bass with a neutral Tone sounds boomy. Heavy bass with a dark Tone sounds balanced and deep, because the top end has come down to meet it. If your low end sounds overbearing, try lowering Tone a couple of dB before lowering Bass.

Reverb and Space. Bass feeds the reverb. Long decays accumulate low-frequency energy because the tail's damping affects treble more than bass. Heavy bass plus long Space is the recipe for rumble.

Width. No direct interaction, though very wide settings can push left or right peaks higher, which compounds any headroom problem.

Recommended Bass by goal

Mistakes with Bass

• Maxing it by default. +12 dB is the top of the range, not the standard. Most tracks sit between +4 and +8.
• Setting it on headphones only. Open-back headphones and big over-ears flatter low end. Check on earbuds and a phone.
• Blaming the encoder for clipping. The 96 kbps MP3 export does not add distortion of that kind. If the kick crackles, the boost pushed it past full scale before encoding.
• Boosting into a long reverb. Rumble in the tail is bass, not reverb. Trim Bass first.
• Forgetting the negative range. -6 to 0 dB is there for sources that are already thick. A muddy source gets muddier when slowed; cleaning it up first helps everything downstream.
• Treating Bass as a loudness control. It is not. Raising it makes the low end louder relative to everything else. If the whole track feels quiet, that is a mastering question this editor does not address.

Bass and the export

The exported MP3 is 96 kbps at 32 kHz, encoded in a web worker in your browser. Low frequencies are cheap for an MP3 encoder, so a bass-heavy edit loses very little at this bitrate. The limit is headroom, not format: anything that clipped in the preview is clipped in the file. The export is fine for YouTube, TikTok and Shorts, which re-encode everything anyway. For a release master, work from a WAV source in a DAW with a proper limiter.