Simple question: Four speakers are sitting on a panel discussion, I want to gently squelch the 3 mics not in use, simply to remove ambient noise. I need a tool that simply detects which mic is loudest (pretty simple right?) and mutes the other three. Any advice? Really need this tool, fairly frequently. Thanks!
Audacity does not process the sound as it is being recorded, so you would need to either apply your automatic volume control (somehow) before the sound gets to Audacity, or adjust the levels after it has been recorded.
How are you recording your 4 microphones?
Hi Steve, yes, of course we’re looking for a tool in the editing process (not live recording).
The reason I keep having this requirement is, I’m an event videographer and you can never control the set. When I have one or two speakers I can just put a wireless mic on their body And when there’s only one PA mic, I can just attach my own mic to the podium.
My problem arises when there’s multiple microphones on the panel, or aisle mics for audience QA, or a play, for example where I’m capturing audio from multiple microphones on the set. Typically some tracks are captured into one of the cameras, and other tracks are on Zoom H1 recorders. I can edit the sound in Vegas, too but Audacity is more convenient in some cases.
OK, so in Audacity you have each microphone on a separate audio track?
If that’s the case, then the level of each track can be manipulated.
The method that affords greatest control is to adjust the levels manually using the envelope too: Audacity Manual
This method is very effective, but is rather fiddly and can take ages for long recordings.
Automated methods, such as applying a noise gate, are much quicker, but can be a bit hit or miss.
A combination of; first apply an automated effect (such as a noise gate), and then tweak the result manually where necessary, will often produce the best compromise between production quality and time taken.
What should happen if two mics are loud at the same time?
The editing process I use now is simply selecting the unused tracks and throwing a 30db gain reduction on them. after the first action, of course, to reapply the same gain adjustment is R.
If one or two of the tracks are used more than others, then you put the most-used tracks at top and bottom of the display, in order to allow you to select three tracks at the same time to apply the gain reduction.
Another technique is just load all these audio tracks in Sony Vegas, “Group” them all, and then apply Splits at each point you want to change microphones. Click on the good track, hit U to ungroup it and then click on any of the other tracks and hit Delete. All the unused tracks disappear at once. Technicallly this has fewer manual operations for the same result but Vegas doesn’t seem to display the audio sharply enough to judge which track is muddy, versus clear, when two tracks are of equal gain. You need to see that to move fast. You can almost edit the whole project without listening to it, if you can get the audio displayed clearly— you can see which track is loudest, and you can see whether the audio is sharply defined or muddy.
But now, I’m tired a this and I want it automated.
The place to start with this is with appropriate types of microphone and careful microphone placement so as to achieve the best “separation” that you can in the original recording, and to make the recording in a quiet room with minimal room echo. Get that right and you may not need to any post-processing other than editing.
What sort of mics are you using, and what is the room like?
If the recording is reasonably clear and you have a good amount of voice separation, a “Noise Gate” effect may help to make it a bit clearer. There is a Noise Gate plugin here: http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Noise_Gate
Installation instructions: http://wiki.audacityteam.org/wiki/Download_Nyquist_Plugins#install
Note how far apart these two are. That’s not accidental. You can’t see it, but they’re sitting on a WNYC SoundStage.
Koz