Fault by fault
What a sanctuary adds, and what is repaired.
The check in your browser names background noise, mains hum, clipping, dropouts and muffled sound, with their times. The try repairs the first 20 seconds on Solipsium's server and lists a reason for each step.
Hum from the desk.
A ground loop between the desk, an amplifier and a computer puts hum at 50 or 60 Hz and its multiples into the recording. Where those lines stand 10 dB over their neighbours, they are notched out in bands 3 Hz wide: “Mains hum was found, so it is notched out before any cleanup.” Hum that comes and goes, with the lights or a heater, is notched only where it plays: “Mains hum was found in parts of the recording, so it is notched out there; the voice is put back wherever the notches removed nothing.”
Hall echo.
A tall room with hard walls rings after every word. Echo reduction runs only when echo is the one thing found, with no steady noise, music, hum, clipping or muffled sound beside it. On a longer recording it works about 20 seconds at a time. The result reads: “Room echo seems to blur the speech, so echo reduction is used.”
Heating and air handling.
A steady fan in the building is a noise floor. A steady floor within 26 dB of the voice gets Full-band speech cleanup, a speech model that keeps the voice's full range and lowers what surrounds it. The result reads: “A steady noise floor was found, so it is removed.”
The congregation.
Voices behind the preacher get speech cleanup too: “Other voices seem to sit behind the speaker, so speech cleanup is used.” A cough or a baby crying is a short sound, not a steady one, and is usually left.
A raised voice that clipped.
Flat tops up to 10 ms long are partly raised back from the undamaged samples around them, never more than 2.3 dB over the clip level. A top that is unsafe to raise is left exactly as it was.
