Subject:Annoying Hum! Please help.

Posted by: trumpetprof

Date:6/6/2004 7:24:14 PM

I just bought Screenblast Sound Forge 7.0, and have an annoying problem! There is an electronic hum in everything I record. I've tried using the eq to get it out, but it is still not presentable. Is this a problem anyone else is having? I'm recording with a digital microphone. Thanks for your help.

Subject:RE: Annoying Hum! Please help.

Reply by: Geoff_Wood

Date:6/7/2004 5:38:16 AM

A digital microphone ?!!!

Please explain exactly what you have connected to what, in what order. Sorry, too cryptic to answer otherwise.

geoff

Subject:RE: Annoying Hum! Please help.

Reply by: trumpetprof

Date:6/7/2004 8:58:08 AM

Geoff:

The microphone is the one I use for my mini-disk recorder (perhaps this is the problem). I simply have the microphone inserted in the 1/8th inch microphone plug in the back of the computer. Even though I have a PhD, I'm an idiot when it comes to electronics, so I appreciate your assistance.

Subject:RE: Annoying Hum! Please help.

Reply by: Chienworks

Date:6/7/2004 1:08:58 PM

Impedence mismatch most likely? It's also probably an electret mic and the computer's sound card might not be feeding it the correct phantom voltage.

Subject:RE: Annoying Hum! Please help.

Reply by: trumpetprof

Date:6/7/2004 3:14:33 PM

That may be it. I'll keep working with it. As it stands now, I can't use the software. Thanks for the advice.

Subject:RE: Annoying Hum! Please help.

Reply by: Chienworks

Date:6/7/2004 3:51:31 PM

It might be worthwhile to try a different mic, just as an experiment. You can pick up a cheap dynamic mic at RadioShack for a few bucks. Dynamic mics aren't as good as electret (especially in this price range), but it should be relatively free from impedence problems with your sound card. If you don't get hum with it then you'll know that the computer, sound card, and software are working well. If you still get the hum then your original mic is probably ok and we'll have to look elsewhere for a soluiton.

Radio Shack 33-3024 $14.97. Unfortunately it's got a 1/4" plug on the end so you'll need an adapter to make it fit.

Look around the store if you want and you may find something like a tie-clip lavalier or a dictation mic cheaper. After all, this is just an experiment to find out where the problem is. You won't expect to record any music with it.

Subject:RE: Annoying Hum! Please help.

Reply by: MJhig

Date:6/7/2004 4:34:44 PM

Wal*Mart's got PC mics for under $10. They don't need to be adapted and you can stick it on an internet PC for voice conversions using MSN Messenger etc. after the experiment.

Also, did you set the mic level in the soundcard's RECORDING window? Possibly the level is all the way up and you're hearing the soundcard's preamp squawking.

MJ

Subject:RE: Annoying Hum! Please help.

Reply by: trumpetprof

Date:6/7/2004 6:52:15 PM

Thanks for the replies. I think I'll try a different mic, so I'll head to radio shack tomorrow. I recorded a few sessions on mini-disk, and then dumped them into Sound Forge -- no hum present. This means it must be a mic problem, not a software problem. I'll post results after the next experiment. Again, thanks all.

Subject:RE: Annoying Hum! Please help.

Reply by: MJhig

Date:6/7/2004 9:46:32 PM

Mmmm, you did check your soundcard's mixer didn't you?

MJ

Subject:RE: Annoying Hum! Please help.

Reply by: rraud

Date:6/8/2004 10:41:00 AM

As Chien stated, It's possible that your mic needed a power source (bias power) as is supplied on the mic input jack of many MDs. Most consumer PC sound cards do not supply power for electret mics.