Mis has static while overdubbing, but none when recording

[NathanialColtingway]

I'm not exactly sure what the problem is, here. I'm using the latest version of Audacity at the time of typing this (2.0). I recently switched to the new version from the 1.3 BETA (I believe it was 1.3.13), and that's where everything of mine was originally recorded. On 1.3, the recordings have suddenly gotten strange. Whenever I'm recording an overdub (as opposed to a standalone recording by itself), the microphone gets all static-y, as if it's really old or damaged. However, when I record some simple dialogue with nothing accompanying it, the recording is just fine. I switched to 2.0 recently due to this, but the issues persists eve in the new version. I have no idea why it's only doing it for the overdubbing, but I really need some help here. I'm thinking it may have something to do with the tracks themselves somehow. Mostly, the tracks are all my own vocals, except for the instrumentals.

And in case you're wondering:
OS - Windows 7 Home Premium x64
Microphone - Blue Snowball

I didn't receive any sort of error message or anything. Whatever is going on here I guess Audacity isn't catching.

[kozikowski]

That's exactly what happens when you go through a USB hub on the way to the computer. Multiple pathways and sound management do not work well through a hub -- or anything else that can affect connection speed.

Koz

[steve]

What sort of "static"?
Do you get sudden bursts of loud noise that replace the audio, or is the audio present but "distorted" or something else?

[NathanialColtingway]

Yeah, I'm using a USB mic. And the audio is there but distorted, big time. Lots of static.

As of typing this, the issue actually fixed itself, but I dunno how. I kept opening and closing Audacity, checking it each time, and it eventually righted itself. But for the future, if it happens again, is there any way to fix it besides just opening and closing the program?

[steve]

The two most likely causes are:
1) There is a USB data connection problem that is causing the data to be corrupted.
2) When you combine multiple tracks, the overall level is going above 0 dB and so causing distortion.

(2) is the easiest to recognise and remedy. When you play back the tracks, look at the playback meter. If the level goes all the way up to 0 dB then it is too loud and will cause distortion. The playback level of each track can be adjusted using the "gain" (volume) slider on the left end of the track.

(1) can be a lot more difficult to fix, but keeping the load on the computer to a minimum will often help, so avoid running other programs at the same time as you are recording. In particular, watch out for programs that try to update automatically (such as Windows Update and antivirus programs) as these can grab too much of the computer resources and cause the USB to mess up. (USB hubs are also a common culprit for USB connection problems)

If you get the problem again, use "File menu > Export Selection" to export a short selection of the problem track (just a couple of seconds) and export in WAV format. The WAV file can be uploaded to the forum by using the "Upload attachment" feature (below the message composing box). That will help us to diagnose the problem.

[NathanialColtingway]

It's definitely not the volume or anything like that. The USB data connection sounds more like the problem. I usually run everything at once, and although I don't run much, I run enough, so that's probably what it was. I still haven't had the issue again, but if it persists, I'll try shutting off my programs one-by-one and going back to test the mic after each one, restarting the program each time, of course.

Thank you guys so much for your help. If it starts up again, and leaving everything else closed doesn't fix it, I can upload a sound clip of something so you guys can hear what I'm hearing. I'm hoping that won't happen, though.

Thanks again, everyone.

[NathanialColtingway]

Everything was working fine until today. I don't know why it only ever happens when overdubbing; if there's a single track present when I start recording, the static starts right back up. I've uploaded a little sound file of what happens when I try to record over anything else, whether it's music or just another track that I recorded:

http://www.2shared.com/audio/FyEifugb/I ... ening.html

I said before that restarting Audacity a few times eventually made it go away, but this time, it refuses to go away, and I'm at my wit's end. Please, can anyone tell me how to permanently fix this annoyance?

[steve]

I don't know why it only ever happens when overdubbing;

Because the USB has to handle twice as much data. There is data coming in (recording) and data going out (playing) at the same time.
Zoomed in close, you will see at roughly the middle of this image there is a discontinuity in the waveform.
What has happened is that the USB was not able to keep up with the audio data, so there is a bit of the waveform missing.

firsttrack000.png (7.65 KiB) Viewed 1722 times

USB is a bit prone to this problem because it was not originally designed to handle continuous data and it is dependent on CPU availability. The greater the load on the computer the more likely this problem is to occur.

Although most common with USB, the issue can also occur to hard drive access. Again the drive is having to cope with continuous reading and writing at the same time. In fact the problem can be due to a data bottleneck almost anywhere in the system - the one thing that is sure is that somewhere in the system there is a bottleneck and data is not being passed through fast enough.

restarting Audacity a few times eventually made it go away, but this time, it refuses to go away,

There's a good chance that the "trigger" for the problem is that some other process is using the system and tipping it from "being able to cope" to "not".
A common culprit is Windows Update. Other common culprits are programs that periodically check for updates (such as security products) and programs that periodically run "scans" (such as anti-virus programs and disk defrag utilities). Looking in the Task Manager to see what is running can sometimes help to pinpoint the problem. Rebooting the computer can often work as a temporary workaround.

There's a list of suggestions of things to check on these pages:
http://wiki.audacityteam.org/wiki/Troub ... ings#Skips
http://wiki.audacityteam.org/wiki/Manag ... #resources

[DiDiKoYouKnow]

So has there been a solution?

[steve]

So has there been a solution?

I doubt that NathanialColtingway will reply 7 years after his last post.