Help with a recording problem/audio distortion

Post by **mightyfelix** » April 19th, 2019, 10:10 am

I've been trying to help a newer reader for one of my BC projects finish up her section, and she's had some trouble with distortion showing up in the audio file. I'm not sure if this is a hardware or software problem, or if there's anything she can do to avoid this in the future. Here is a sample. The distortion begins very abruptly at about 0:18, and continues on to about 1:13, when we have some residual crackling and then a few seconds later, it seems to go back to normal. Any ideas?

https://librivox.org/uploads/xx-nonproject/facesinthefire_distortion.mp3

KevinS · Post by **KevinS** » April 19th, 2019, 11:04 am

Does your reader identify this in the original, or only after it's been exported (or otherwise modified)?

EDIT: The reader has a nice voice.

Post by **mightyfelix** » April 19th, 2019, 11:05 am

I think it's in the original. She said she was working on editing, when suddenly she came across this portion.

Post by **TriciaG** » April 19th, 2019, 11:30 am

It sounds electrical to me, which could be almost anything - the mic, the computer, some sort of weird electromagnetic interference in the environment.

I have no clue.

tovarisch · Post by **tovarisch** » April 19th, 2019, 11:59 am

Sounds to me like a bug in the software that somehow adds earlier samples to the later ones, producing the echo. Possibly the software ran out of resources, maybe the OS was doing something during those seconds - checking e-mail, running updates, whatever.

Does the newer reader use headphones while recording? Sometimes the feedback comes from a point with electrical interference already in it, so the reader can stop and wait it out...

Post by **mightyfelix** » April 19th, 2019, 12:01 pm

Not sure. I've given her the link to this topic, so hopefully she'll stop by and chime in.

iBeScotty · Post by **iBeScotty** » April 19th, 2019, 1:13 pm

Hard to tell the cause but it sounds like a power supply issue, if I were to guess. I’ve had similar sound degredation when recording remotely (for video projects) when recorder batteries were dying and thus not giving good voltage to the condenser mic. Assuming she is using a usb mic, is it plugged into a hub? Could try a powered hub or different connection direct to the computer.

KevinS · Post by **KevinS** » April 19th, 2019, 1:27 pm

I wear my tinfoil hat, which seems to help in a lot of ways.

lurcherlover · Post by **lurcherlover** » April 23rd, 2019, 12:31 am

This could be moisture in the mic, especially if it's a condenser (capacitor) mic. If dampness and dust etc gets onto the diaphragm it can behave like this. I would recommend you put it somewhere warm like an airing cupboard or in a box with a very low powered (5 Watt) lamp bulb to dry it out (but be careful of it overheating and any possible fire risk). It may take a day or two to dry out. It's always best to keep mic's in dry conditions and in their original boxes to avoid dust and dampness creeping in, as it will degrade the mic over time. Use silica gel as well to absorb any damp. Mic's are delicate things and need a lot of care.