Volume booster sounds crackly? Here is why
You install a booster, drag it up, and the music turns into a buzzing mess. This is the single most common complaint about volume booster apps, and it is not a bug in your phone. It is what happens when an app raises gain and does nothing else.
What clipping actually is
Audio is a waveform with peaks. Your device can only output up to a certain level. When an app multiplies the signal, the peaks hit that ceiling and get flattened — the tops are literally cut off. Flattened peaks are not quiet, they are a different sound: a hard, buzzing edge that gets worse the more you push. That is clipping, and no amount of volume will fix it, because it is already at the top.
Why it is worse on some tracks
Modern commercial music is already mastered loud, with very little headroom left. Add 10 dB on top and there is nowhere for the peaks to go. A quietly recorded podcast has plenty of headroom, so the same boost sounds clean. If one track distorts and another does not, that is the recording, not the app.
The fix is a limiter, not a lower number
A limiter watches the signal and pulls down only the peaks that would clip, leaving everything else alone. The result is louder without the hard edge. Android has this built in as DynamicsProcessing, and an app can run it alongside the gain — but most booster apps do not bother.
This is the practical test when you are choosing one: does it mention a limiter or distortion protection at all? If the whole pitch is a big percentage, you are buying gain with nothing behind it.
Things you can do right now
- Back the boost off until the buzz disappears, then note that level. That is your device’s real ceiling.
- Cut the bass rather than raising everything. Low frequencies eat the most headroom, so a small bass cut buys you real loudness.
- For speech, raise the mid range instead of the whole signal. Dialogue lives around 1–4 kHz; lifting there makes it clearer without pushing the peaks.
- Turn off Dolby or the manufacturer’s audio mode while you test, so two processors are not fighting.
What Loudi does about it
Loudi keeps a limiter in the chain the entire time the boost is on, and it marks the upper part of the dial as a caution range: past that point the ring turns amber. You see the warning before you hear it. The maximum is stated as perceived loudness — 200% is about +10 dB, 400% is about +20 dB — rather than an invented number.