Weird problem-household noises?

[polkat]

Running 1.3.14 on an XP SP3 computer. The program works perfectly, but if recording, and anything in the house, like the refridgerator, comes on, I get a loud crack sound in the recording. I've used this same setup with 1.3.13 and earlier versions without having this problem.

Is there some kind of line filter I can use between the computer and the a/c which might help? As you might guess, I don't want to go around the house unplugging everything before I record. Ideas?

[steve]

There are no changes in Audacity 1.3.14 that can account for the problem, It is a "hardware" issue.
Ensure that all of your appliances, especially the computer, are correctly earthed and where possible avoid using extension leads or multi-way power adaptors.
An "anti-surge" plug may help alleviate the problem (for example: http://www.amazon.co.uk/Mercury-Anti-Su ... B000ROLJL8 ) though I can give no guarantee that it will entirely cure it. It is difficult for us to gauge the severity of the problem that you are describing, but unless it is "fairly mild" the best course of action may be to consult an electrician.

I remember as a child, my father would unplug the refrigerator before making recordings so as to avoid clicks as the motor started up. Eventually, one particularly warm summer, the milk went off and my mother complained, sending my father out to buy an "anti-surge" plug ... which cured the problem.

[kozikowski]

What are you recording? Computers are remarkably resistant to clicks and pops and other electrical disturbances, particularly laptops many of which run from the internal battery all the time, whether they're plugged in or not.

Not so consumer sound equipment. I have a large sound system connected to my home computer and I can tell exactly when the fridge kicks on. If I make recordings divorced from the house -- like floating microphone directly into the computer, it doesn't make any difference at all what the house does. But the instant I plug in a mixer or other device plugged into the wall, then that's the end of the clean sound.

It does help if everything is plugged into one wall plate. Accidentally plugging half your system into one "side" of your house and the other on the other is begging loudly for trouble. In the US, power is delivered at 240 volts and split up into two 120s for each half of the house. The washing machine could turn on and unbalance the power for a split second. Just long enough to cause problems.

I've owned two houses and they each had at least one wall socket wired wrong.

Koz

[kozikowski]

There is one diagnostic thing you might consider

Set Audacity preferences for Playthrough, close the panel and click once in the red Audacity recording meters. That will turn all the recording services on except actually capturing anything. You can turn the speakers up and listen for problems while you mess with the wiring. If you wiggle the refrigerator plug in the wall and the computer sound goes nuts, then you may have located the problem.

Koz

[polkat]

Same setup as I've always used. A simple dynamic mic into a preamp into line in on the sound card. Never had this problem until I went to 1.3.14. I'm not saying the problem is in Audacity but...

[steve]

You can get the old 1.3.13 version here if you want to temporarily downgrade and test: http://code.google.com/p/audacity/downl ... nloadCount

[whbjr]

If you wiggle the refrigerator plug in the wall and the computer sound goes nuts, then you may have located the problem.

Another good test, perhaps easier to set up, is to plug a vacuum cleaner into the wall outlet (perhaps trying several different outlets), and turn it on and off while recording. They generally have fairly powerful motors, capable of producing quite a spike in the power lines, and the On-Off switch is easier to control than the refrigerator's wall plug!

When possible, I do home-studio recordings on my laptop, with the AC power adapter unplugged - battery power only.