Audacity Forum

lonepilgrim · Post by **lonepilgrim** » Fri Mar 30, 2018 7:39 pm

As I remember, when I 1`st started using Audacity several years ago I was able to record acoustically with out much background noise and that the recording level indicator stayed near 0 most of the time...since then..I don`t know why...they consistently stay around 45
In addition...I get a pretty loud background hum that I`m guessing has something to do with 60 Hz wiring here which I really can`t avoid
I am able to suppress some of it with noise reduction but it`s always there..I`ve removed every light bulb in this apartment..turned everything electrical off including the refrigerator...I always have indicator up just below 1/2 even when I`m not recording and a high pitched hum in the background...even when I not recording...can you tell me what I`m missing ?

Post by **kozikowski** » Fri Mar 30, 2018 8:12 pm

can you tell me what I`m missing

The shield on your sound cable?

http://kozco.com/tech/audacity/clips/OpenShieldHum.mp3

There are specialized sound tools to try and help that, but it's far better that you fix the cable.

It can be pure greasy dirt. If you have guitar amp cables...

...swab the male metal end down with alcohol and a rag. Window cleaner works OK. Dry it off and try it again. When you plug it in, give it a quarter turn to make sure all the contacts inside meet.

Koz

lonepilgrim · Post by **lonepilgrim** » Fri Mar 30, 2018 10:03 pm

thanks....but it`s still doing it..I have a Shure SM 57 thru a cheap cable into a low impedance f/m connector but I just disconnected the cable unplugged everything including the computer fan...im thinking it might have something to do with the computer..it`s been doing this for a while

Post by **kozikowski** » Sat Mar 31, 2018 1:13 am

Post a sample.

It's best if you send some normal talking and background sound. Not just a noise sample.

You can use this as a fuzzy guide.

http://www.kozco.com/tech/audacity/Test ... _Clip.html

Don't cut us short, either. Nobody can analyze two seconds.

Koz

Post by **kozikowski** » Sat Mar 31, 2018 1:24 am

The goal here is not to ring a bell and tell you exactly what the problem is. It's more like group wisdom and someone having similar problems once and their experiences.

Are you talking about an XLR to 1/8" adapter that goes into your soundcard?

Is it all the way in? I had one soundcard where the plug would stick halfway. It felt like it was perfect...but it wasn't.

If you disconnected it and all other cables and it's still doing it, then the soundcard may be on the way out, or the computer itself. Most soundcards use the power from the computer with no filtering or corrections. Both of those cost money.

Are you good with mucking around inside your computer? Shut everything down, pull the cover off and reset the soundcard. Pull it out, admire it and shove it back in (carefully).

The goal is to notice a change. Even if the hum doesn't clear up, if your symptoms change that may tell us more about the problem.

Koz

lonepilgrim · Post by **lonepilgrim** » Sat Mar 31, 2018 1:54 am

I`ll get that to you...the setup is a low impedance mic SR57 and a cord going to my 4 channel mixer female connectors on both ends of the cord..I monkeyed around with some of the settings and managed to tone it out a little bit..not sure what i did..thanks

Post by **kozikowski** » Sat Mar 31, 2018 1:57 am

low impedance mic SR57

I know what an SM57 is. I used to own one.

managed to tone it out a little bit

Post a sample. If it's not really bad or crazy complicated (lots of overtones), we may be able to help.

Koz

Roger Hågensen · Post by **Roger Hågensen** » Sat Mar 31, 2018 9:25 am

When possible use a XLR to XLR balanced mic cable, assuming the mic and the mixer/input device supports it. Most pro and semi-pro gear should.
The "balanced" wiring will get rid of any noise or hum that affect the positive and negative leads equally, so any hum in the electrical in a room should be removed with this (assuming the mic element itself doesn't pic it up).

I even had (have) a homemade XLR to TRRS cable let me get rid of the hum in my PC (that was picked up by the line in) sure I had to invert the audio of the right channel and mix them at 100% volume to make it work, but it did work.
Later I got a external mini mixer with balanced XLR mic inputs made this very easy.

The SR57 should be a balanced mic, but the XLR to TRS jack (as opposed to a TRSS jack) crosses the ground with the negative and you end up with a unbalanced signal, so any electrical noise gets recorded as well.

FIY! Sometimes with cheaper mics you can open the mic and re-wire it to be balanced. There is no way to rewire a XLR to TRS cable though, usually they lack the extra wire (to save on cost) so you can't remove and re-solder a TRSS jack on the cable.
My advise would be a XLR to XLR cable and get a XLR to TRRS jack adapter (a small plug you connect at the end of the cable), that way you can connect to the XLR of a new mixer with your mic later for example.

Post by **kozikowski** » Sat Mar 31, 2018 12:15 pm

When possible use a XLR to XLR balanced mic cable

All that is correct, but from the posting: it used to work.

Also from the posting, there is no SR57.

Koz

lonepilgrim · Post by **lonepilgrim** » Sat Mar 31, 2018 9:25 pm

Sorry..Shure SM-57..standard mic...the thing is...perhaps i`m not explaining it right...i get background noise all the time...I`ve unplugged everything from the computer..the mic...the mixer....there is nothing physically connected to the computer and i still get this hum...here is the sound sample you asked for with mic and mixer connected...I`m also going to send you a sample of as I just described..Audacity program running...nothing physically connected to the computer.

Audacity Forum

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