Microphone trick

crazyjman

crazyjman

Member
I recently read in an article that to get a good recording to cover all the frequencies a good technique to use is 2 identical mics aimed directly at the grill, one at 2 o'clock and one at 8 o'clock but having the phase reversed on one mic.

Could someone explain how you go about reversing the phase on a mic. (I hope I explained this properly)
 
ya but doesn't that sound cool. ( not that I have another identical mic right now, I just thought it was pretty interesting)
 
crazyjman said:
I recently read in an article that to get a good recording to cover all the frequencies a good technique to use is 2 identical mics aimed directly at the grill, one at 2 o'clock and one at 8 o'clock but having the phase reversed on one mic.

Could someone explain how you go about reversing the phase on a mic. (I hope I explained this properly)
Click to expand...


Many mic pres and mixers have phase reverse switches, or you could use a mic cable that's wired out of phase with another cable.
I may suggest reading up on mic placement and phasing issues. You may or may not be happy with the results of phase cancellation.

Terry
 
Fair enough but one last question;
I use sonar 3 and on the track control it has a phase inversion button. Would this do the same thing if I recorded each mic to a separate track?
 
This is direct quote from the article I was reading from

http://www.homerecordingconnection.com/news.php?action=view_story&id=39

Huge lead guitar.
To do this you need two identical mics. Take the first mic, and place it in front of the speaker. For our example, we'll say a sm57, 2" from the dust cap, at 2:00, right up against the grill, no angle. Take your second sm57, and place it "mirror imaged" from the first mic. This would also be 2" from the dust cap, right up against the grill, no angle, but at 8:00. Place one mic out of phase with the other, and record on two separate tracks. Pan them far apart, and you will have a giant sound. What you have actually done is to set up a comb filter, and between the two signals, you are pretty much covering every available frequency.
 
crazyjman said:
Fair enough but one last question;
I use sonar 3 and on the track control it has a phase inversion button. Would this do the same thing if I recorded each mic to a separate track?
Click to expand...


Yes, the phase inversion button in Sonar3 will do the same thing.

Terry
 
Another fun thing to do is just set up one mic close and another one at a distance(experiment). Pan them hard left and hard right. You shouldn't have to use any phase reversal.
 
wouldn't you get phase cancellation when using this techinque? the 2:00 and the 8:00 of the speaker should be in phase with one another already right, so putting one mic out of phase would seemingly just cancel the two out.
 
I fail to see how two microphones which will have limited frequency range can possibly cover 'every frequency'. Or does it mean every frequency the mic covers?
 
That would practically cause a 180 degree phase cancellation in my mind. Although the frequencies at 2:00 and 8:00 technically wouldnt be EXACTLY the same they would be close enough.

Basically the effect you would get is a very wide stereo feild with no center and weak low end. This is only if its panned, not centered. In my opinion it wouldnt sound huge, just really wide and unfocused. And if you ever put it into a mono source the guitar would practically disappear all together. Not a good idea.

Now not reversing the phase of one channel and panning them hard left and right would probably give the more desired effect.

Danny
 
I don't understand the "comb filter" reference in the article. What is a comb filter and how would this achieve it?
 
I use a technique that only seems to work on old Marshalls. Take a 57 point it at where the dust cover meets the cone. Take another 57 and point it at a 45 degree angle to the first one, the heads can touch. Throw one of them out of phase. Mix the 2 mics together and pan them the same direction (or mix them to the same track. It gives you a nasal-y sound that fits very well into the mix.

BTW MCOLLING. comb filtering sounds like a flanger or phaser effect, it is caused by different frequencies getting cancelled or reinforced when 2 similar but out of time sounds get mixed together.
 
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