SOLIPSIUMAlpha
SOLIPSIUM Super resolution audio engine
Rumble
Solipsium finds steady low rumble under a voice and turns the sound below 300 Hz down towards the recording's own quiet floor. Drop a recording to hear its first 20 seconds repaired, free, with no account.
Drop a rumbling recording here
Solipsium checks it in your browser for clipping, hum and noise, without uploading it. Rumble is measured on Solipsium's server when it repairs the first 20 seconds, with no account.
WAV, MP3, M4A, video and more, up to five minutes.
After signing up, drop the same file into the editor to repair all of it.
Then drop the same file into the editor. Scans and short repairs are free.
What rumble is
Rumble comes from wind, traffic, air conditioning and a handled microphone. It sits below about 100 Hz and keeps going through the pauses between words, so the repair measures it there.
The repair labels rumble when the band from 30 to 80 Hz stands 10 dB over the band from 150 to 400 Hz, is loud enough against the voice to be heard, and fills the band evenly. A held bass note peaks far above its neighbours and is not labelled. A voice pitched under 80 Hz is left alone.
How it works
The repair measures the band under 300 Hz once and turns each part of it down by how much rumble it holds. The result of the first 20 seconds lists its reasons.
The band is measured in the pauses and over the whole recording, then turned into one curve that every channel gets. When the step runs, the result can read: “Low rumble was found under the voice, so after every other step the steady noise below 300 Hz is turned down towards the recording's own quiet level, with one fixed curve for the whole recording; where the recording is much louder than the rumble at a frequency, that frequency keeps nearly all of its level.”
Rumble is turned down as the last step, after any holes, crackle or hum are repaired. The step measures again on what it is given, and if no rumble is left it passes the recording on untouched.
Steady low wind is rumble. A gust that overloads the microphone distorts the sound, and turning the low band down does not undo distortion. Where gusts flattened enough peaks at the converter's limit, the recording is labelled clipping, gets the clipping repair and skips the rumble step.
Questions
The check in your browser has no rumble finding, though it may list background noise. Rumble is measured on Solipsium's server by the repair itself, when you press Repair the first 20 seconds.
Each frequency under 300 Hz keeps the part of its level that matches the recording's own quiet floor, and a frequency where the voice stands well above the rumble keeps nearly all of its level. Sound above 300 Hz is barely changed. Compare Original and Repaired on the same words to hear what it took.
The try can turn steady low wind down in the first 20 seconds of the video's sound. Drop the video file as MP4, MOV, MKV or WebM; the check reads its sound when your browser can open it and the video runs five minutes or less. In the editor, a video export keeps the original picture with your repaired sound track. For noise and hum in a video's sound, see removing background noise from a video.
The rumble step is skipped when a cleanup or a treble rebuild ran before it: steady noise, other voices and echo each bring a cleanup. It never runs on a recording labelled clipping. Solipsium's free try is built for speech, and on a recording labelled music the step is skipped, so a bass line keeps its level. Rumble that is faint next to the voice is not labelled at all.
Handling noise that keeps going through the pauses counts as rumble. A single knock on the desk is too short to raise the level of the pauses, so it is not labelled rumble and this step leaves it alone.
Not for the check, which runs in your browser. Pressing Repair the first 20 seconds sends those 20 seconds; when your browser could not open the file, or it runs over five minutes, the file itself goes to Solipsium's server, so the try is offered for it only up to 25 MB. Solipsium keeps only the first 20 seconds and deletes them within an hour. If you are signed in, a file you drop or choose is uploaded to your account and opens in the editor instead. The privacy notice has the rest.
Free audio tools
More pages for noise that sits under a voice.
Check a recording for noise, hum and clipping, then hear its first 20 seconds repaired, free.
Mains hum at 50 or 60 Hz and its harmonics, measured and notched out, even when it comes and goes.
Steady hiss is measured as background noise in your browser, then lowered in the first 20 seconds for you to hear.
See the noise, hum and clipping in a video's sound, measured in your browser, and hear the first 20 seconds repaired.
Every free tool on one page.
With a free account, the editor runs the same repair on recordings up to 30 minutes long.
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