Foam Cone for Microphone

[DaisyCutter]

Been looking into the Auralex stuff, moving blankets, and other assorted solutions to help deaden the ambient noises during recording.

Rather than covering an entire room with foam to keep noises from bouncing back, wouldn't a foam mic cone do the same thing by keeping out sound that isn't coming in directly in front of it?

Sort of like those cones they put around dogs necks after surgery or something.

 

[mshilarious]

Been looking into the Auralex stuff, moving blankets, and other assorted solutions to help deaden the ambient noises during recording.

Rather than covering an entire room with foam to keep noises from bouncing back, wouldn't a foam mic cone do the same thing by keeping out sound that isn't coming in directly in front of it?

Sort of like those cones they put around dogs necks after surgery or something.

You will change the response of your mic to something closer to omni by doing that, and you still won't reduce room reflections. You are thinking that sound propagates like light does, so a 'mic hood' would work like a lens hood does on a camera. It doesn't, and it won't. Even a shotgun mic won't work, because room reflections are still coming from the front of the mic.

However you can reduce reflections with close-micing techniques, but that has a definite effect on the sounds you can get.

 

[DaisyCutter]

Darn.
Was hoping to save the time and work of putting all of that stuff up

 

[tkingen]

mshilarious,

Can you explain your answer a little more? I would think that actual room reflections would be diminished in the mic's polar field...especially highs and upper mids, which I understand do react similar to light waves. Is this not true?

Terry

 

[mshilarious]

mshilarious,

Can you explain your answer a little more? I would think that actual room reflections would be diminished in the mic's polar field...especially highs and upper mids, which I understand do react similar to light waves. Is this not true?

Terry

Well there will be a difference in frequency response, sure. But basically, a cardioid mic rejects rear sound because of a delay imparted to the rear signal that causes the rear signal to arrive at the back of the diaphragm at the same time as the front, causing a cancellation of the signal. If you block the rear signal at the rear but not the front, like a foam e-collar would, you are interfering with that cancellation, and creating an omni response.

I just verified this experimentally. Using a Shure SM94 mic, my own male voice, and a 1" thick piece of foam wrapped around the mic, both directly around the side ports, and also on the body of the mic behind the ports (leaving the ports open), in both cases the foam increased rear response at a distance of 2' by 4-8 dB (the best resolution possible on the preamp meter I used). I suspect a greater distance from the source would make less of a difference, but it wouldn't be quieter.