Miking guitar cab

If you cant succeed with one mic (SM57 or there abouts) then you probably wont succeed with 3 mics. Get a good sound with an SM57 and then add mics to beef up the sound if needed. For example if you get a good meaty lo end sound from the 57 then stick a 58 on another speaker to tey and get some hi end but not 5K hi end!! ,
Then if you get a good sound with the 57 and 58, try adding a mic a few feet away from the cab (harder to find a good position for the mic) .This could add some depth to the recording and usually would be mixed in just a little with the 57 and 58.
Watch yer phase though.
 
scrubs said:
Get that first mic really close. Like inside 6 in from the speaker (inside 2 inches is even better). Take the grill/mesh off, if possible. Start with the mic at the junction of the speaker cone and center, angled so that it is parallel with the cone. Have headphones on while you're doing this, so you can hear what the mic hears. Play a little something and move the mic around until you find the "sweet spot." You may need to be right in the center, or out toward the edge. It varies greatly depending on the speaker.
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This is how we used to mike our 4x12 cabs when performing live. Mike one of the top speakers, to reduce the effect of floor reflection. For home recording, make sure the cabinet is on an insulating pad of some sort and throw a quilt over the cabinet and mike to kill room reflections. As scrubs said, play with the placement and angle of the mike relative to the cone.

Your recorded sound will sound a bit dry, since it won't have any of the room in it. You can add a bit of room with delay effect.

On the other hand, if you want to get something like a rockabilly sound, stick the cabinet against the wall of a bare room and put the mike in the middle of the room, crank it up and let it rip. It will sound a bit trashy when isolated but will mix well.
 
I've heard a lot of people talk about phasing when using multiple mics. I'm trying to understand the actual physics of this so please bear with me...

At 70F with dry air, sound travels at about 1130 feet per second. So if you place your ambient mic 2 feet behind the primary mic, we are looking at a 0.00177 second delay. But delay doesn't cause phasing...does it?

One would think that the lenth of a single wave is actually what causes phasing...similar to how noise cancellation headphones work.

My questions is, "Isn't it impossible for one to place the secondary mic with such precision that it doesn't go out of phase with the actual sound waves being picked up by the primary mic?"

Am I totally off base? What am I missing?
 
I have quite a bit of experience with live miking, and quite a bit less with studio miking. That said, I've never seen multiple mikes used on a cabinet during live performances unless it was for redundancy. (I'm talking about small-to-medium club work here, not stadium stuff.)

I guess that in a recording scenario you could place as many mikes as you wanted on a speaker or cabinet, record each to a separate channel, and pick the sound you like best. But David Katauskis makes a valid point about phase effect (unless you are playing a single note the whole time..... ;) )
 
David Katauskas said:
I've heard a lot of people talk about phasing when using multiple mics. I'm trying to understand the actual physics of this so please bear with me...

At 70F with dry air, sound travels at about 1130 feet per second. So if you place your ambient mic 2 feet behind the primary mic, we are looking at a 0.00177 second delay. But delay doesn't cause phasing...does it?

One would think that the lenth of a single wave is actually what causes phasing...similar to how noise cancellation headphones work.

My questions is, "Isn't it impossible for one to place the secondary mic with such precision that it doesn't go out of phase with the actual sound waves being picked up by the primary mic?"

Am I totally off base? What am I missing?
Click to expand...
Delay causes phasing. The shorter the dealy, the higher the frequency that gets canceled. Very short delays cancel out very high frequencies that are out of our range. 1ms delay will cause a flange type sound.
 
Im sure you could be right actually. I dont think it is actually possible to get any two different sources exactly in phase. I could be wrong though.
If they were exactly in phase the whole way throught the song then wouldnt that mean that the two waves are infact exactly the same wave?
 
Let me put it to you this way.

If you placed two stereo speakers in line, with one slightly ahead of the other, and plugged a signal generator into the system and slowly swept the frequency band, at some frequency you will attain complete phase cancellation. This is because at that frequency, the peak of the output wave is presented to your ear as a peak from one speaker and a trough from the other because the distance between the speakers is equal to 1/2 the wavelength of the frequency, and you hear (theoretically) nothing. And if that frequency is a harmonic or undertone of some instrument producing a different fundamental frequency, you won't hear the harmonic.

Separating the speakers by differing distances simply changes the frequency that undergoes phase cancellation.

So multiple mikes in front of any source would need to be exactly the same distance from the source to avoid phase cancellation at some frequency. that said, very small differences in displacement would only effect very high frequencies (high frequency = short wavelength) and very large offsets would only effect very low frequencies.
 
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