Audacity: How Can I Get A Silent Background When Recording Audio?

Profile picture of the author James Liberty by James Liberty Posted: 12/30/2008
I'm sitting in my closet right now, trying to record some audio. Unfortunately, when I sit in silence and then hit the "Record" button on Audacity, my microphone is still picking-up some noise (probably from the computer itself).

In other words, when I hit "Record", I can still see some tiny audio waves moving across my screen.

Is there any way that this can be adjusted? How can I get Audacity to "recognize silence"?
#audacity #audio #background #recording #silent

  • Profile picture of the author JamesFraze
    JamesFraze
    Click (or highlight) where you want silence > Generate > Silence > enter how much you want...

    or

    Effect > Noise Removal > Get Noise Profile > Preview > remove noise

    removing noise reduces the quality of your audio, but it works.


    You will probably also need to install the LAME codec ... PM me if you need help with that part. If you don't , you can't export as MP3.

    Other things you can try:
    Grounding the computer properly (it might be picking up the 60hz hum)
    Silence the fans (but be careful of trapping heat)
    Use a better microphone
    Use a better soundcard (probably best way)

    Look for the S/N ratio (signal to noise ratio) rating on the soundcard (laptops can't really get an upgrade here, but desktops can).

    I clamp my microphone to my desk with a peice of foam on it. That helps some of the fans/noise.

    You can also block some of the audio sounds (like pops when you say "popeye"), but using a screen made of panty hose on a coathanger between your mouth and the microphone.

    (of course a paid solution is more elegant, but that works and costs about 45 cents)

    And, for those of you that don't know, http://audacity.sourceforge.net is the tool we are talking about - it records, edits, mixes sound and it's free.
  • Profile picture of the author Steven Carl Kelly
    Steven Carl Kelly
    I just jumped in to offer you the information, and it looks like James is on it! Good job, James -- my work here is done!
  • Profile picture of the author bgmacaw
    bgmacaw
    One thing you can do is turn down the recording volume. This will make it less sensitive to background noise. You can also edit the sound to reduce noise and overwrite noisy sections with generated silence.

    Of course, a quality mike, like the Shure SM58, helps as does running things through a inexpensive mixer like the Behringer XENYX series, before going into the computer.
  • Profile picture of the author James Liberty
    James Liberty
    Is turning down the mic volume all I can do when recording live?
  • Profile picture of the author bgmacaw
    bgmacaw
    Turning down is about all you can do live. That's why I like having the mixer in front of the computer, to get finer control plus better noise reduction.
  • Profile picture of the author Kevin Riley
    Kevin Riley
    I'm now using an Audio Technica ATR55 shotgun mike. It only picks up anything in a 30 degree cone, so no background noise (as long as my computer is outside that cone).
  • Profile picture of the author Brandon Tanner
    Brandon Tanner
    As JamesFraze mentioned, Audacity's built-in "noise removal" effect is an option, but if you use it you will find that (ironically) it introduces weird artifacts into the recording.

    Short of "soundproofing" your recording space, you will need what's called a noise gate for best results.

    Audacity doesn't have one built in, but as long as you have the VST enabler...

    Audacity VST Enabler

    ...you can use any VST plug-in with Audacity. Here's a good free VST noise gate...

    http://www.vellocet.com/software/VNoiseGate.zip

    Basically once you've finished recording, you'll select the entire recording (Edit > Select All), and run it through the noise gate (Effects > VNoiseGate).

    In the noise gate pop-up, select a dB range (volume level) that's higher than the ambient background noise, but lower than the lowest part of the good parts of the recording. It will then eliminate the background "noise" (provided it's quieter than the quietest parts of the good parts).

    Feel free to send me a PM if you need any help with that.
  • Profile picture of the author James Liberty
    James Liberty
    I just noticed that whenever I run the mic volume auto-adjustment tool in Camtasia, Camtasia sets my mic input volume to the absolute max! Any idea why this is? Is there another volume level on my computer somewhere that I need to adjust?
  • Profile picture of the author John Ritz
    John Ritz
    For silence when recording live, you need a gate/limiter (either software-based or hardware).

    I use a rack-mounted setup that works beautifully, but it's a bit overkill for most audio recordings (I got it for my music studio).

    John
  • Profile picture of the author JamesFraze
    JamesFraze
    You know about double clicking the little speaker in your task bar on the lower right hand of your screen right?

    You can also look in the control panel section, under Sounds and Audio and see if your have "mic boost" turned on, which adds quite a bit of gain, and distortion. Turn it off for the best noise reduction.


    Mute everything that isn't required too (in the advanced section)

    Is there a reason why using the first 2 suggestions I offered do not help?


    Originally Posted by James Legacy View Post

    I just noticed that whenever I run the mic volume auto-adjustment tool in Camtasia, Camtasia sets my mic input volume to the absolute max! Any idea why this is? Is there another volume level on my computer somewhere that I need to adjust?
  • Profile picture of the author James Liberty
    James Liberty
    Originally Posted by Brandon Tanner View Post

    As JamesFraze mentioned, Audacity's built-in "noise removal" effect is an option, but if you use it you will find that (ironically) it introduces weird artifacts into the recording.

    Short of "soundproofing" your recording space, you will need what's called a noise gate for best results.

    Audacity doesn't have one built in, but as long as you have the VST enabler...

    Audacity VST Enabler
    Ummm... my Audacity program no longer opens for me now that I've installed the "Enabler". Even a re-install of Audacity wouldn't work. When I try to run Audacity now, something pops-up that says "Temporary Top Window" and the program doesn't respond. Any ideas?
  • Profile picture of the author James Liberty
    James Liberty
    Originally Posted by JamesFraze View Post

    Is there a reason why using the first 2 suggestions I offered do not help?
    I'd rather not use the post-recording "noise reduction" feature because it makes me sound like a robot.

    I'm also using a Griffin iMic external sound card already... wouldn't that spare me from the 60hz humming noise?
  • Profile picture of the author Thomas
    Thomas
    Put a thick, heavy blanket over your head and microphone.

    (Seriously... just don't suffocate.)
  • Profile picture of the author n7 Studios
    n7 Studios
    It's been a few years since I last did any serious audio editing work, and that was in the days of Cool Tools (before they were bought out by Adobe, and renamed Audition).

    I remember there used to be a way of getting the sound profile of your background noise, and then using that as the basis for removing similar frequencies in the rest of the audio. For example, you'd have an interview, which has some silence - in that "silence" you'd have the natural background sound, which you could select, profile and then use to remove similar sound from the rest of the audio clip.

    Perhaps this is a possible solution - sorry I've not described it very well - it's been a while since I last did audio editing. Perhaps JamesFraze can expand on what I'm trying to say
  • Profile picture of the author Quentin
    Quentin
    when using the noise reduction in Audacity make sure you put it to minium and also record at a good rate like 44,100hz.

    This will allow you to remove the samll hiss but still retain the integrity of the audio to some degree.

    Here is a video.

    Audacity Tutorial

    Quentin
  • Profile picture of the author zerofill
    zerofill
    Originally Posted by Kevin Riley View Post

    I'm now using an Audio Technica ATR55 shotgun mike. It only picks up anything in a 30 degree cone, so no background noise (as long as my computer is outside that cone).
    Your pointing a shotgun at your face and speaking into it...I knew you had issues Kevin lol...

    Lol actually I am checking out their website now haha...
  • Profile picture of the author James Liberty
    James Liberty
    Honestly, I feel like I am just missing a master recording volume or something. There is just no way that I should have to crank-up my microphone input to full-blast in order to get a decent recording.

    Is there a master volume control somewhere that I may be missing? (I run Windows XP).
  • Profile picture of the author garyf
    garyf
    If you're making voice recordings it's a good idea to run the Audacity Effects>Low Pass Filter on them. Set the frequency to 100Hz or so to eliminate things like mains hum, fan noise and so on. This frequency is below the human voice so won't affect that.
  • Profile picture of the author samstephens
    samstephens
    Here's a simple solution: put a blanket over your head.

    Sounds strange, but I have mates in the movie industry who swear by it as a cheap sound recording studio you can do at home.

    Just sit on the floor, grab your microphone, and then cover yourself with a blanket.

    The blanket will dampen sounds and echos.

    Hope this helps!

    cheers
    Sam
  • Profile picture of the author John M Kane
    John M Kane
    Harlan Hogan sells sound isolation box,
    Harlan Hogan - Voice overs Narrations Commercials Promos
    Looks just what you might need
    He might even be a warrior here

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