Micing amp with 2 mics. Phase issues.

D

DAS19

New member
I posed this twice last night but it didnt go through for some odd reason.

Anyway, I am reading a tutorial on how to record an amp with two mics. This guy suggests to use a LDC about 5-6in away from the center cone of the amps speaker. He then says to place a 57 on the grill of the speaker off axis.

He says you should notice that the two mics are out of phase and you should go move the 57 until it sounds like an airplane and becomes in phase. Now wouldnt it just be easier to tell us the right spot is 5-6 back offaxis so its hitting the mic at the same time as the ldc? Should I keep the 57 there and change the phase afterwards? I like to be able to monitor my sound before hand.

Can anyway help me get my two mics in phase but keep one 5-6in back and one close to the grill?

Dave
 
Hi...

first thing is find which speaker is best. A quick way to do this is to put the amp on standby, unplug the cable from the guitar, stick your ear up to each speaker and find the one where the loudest 'hiss' or 'hum' is....put your 57 close to the grill there (or preferrably listen to where it sounds best as you move it around while playing).

Keep your trax in mono, and while playing (or someone else is playing)..bring in the condenser and listen to how it effects the 57. if the tone gets thin and small..it's out of phase.

Now ...personally... I like to put an LDC a foot or more back from a tube amp, as I'm trying to incorporate a bit of room and air to be captured along with the direct signal.

Once things are phase alligned, then pan the trax apart and the seperation will be there, and the phase will not.

Other ways to do this is if the LDC is out of phase, just flip the phase on the track....or zoom in to the wave file if you're working in a DAW and allign the waveforms.

Cheers,

-LIMiT
 
DAS19 said:
Now wouldnt it just be easier to tell us the right spot is 5-6 back offaxis so its hitting the mic at the same time as the ldc?
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Of course it would be easier ;). It just wouldn't necessarily be right. The reason he is recommending the 57 be frenching the grille is because that is the sound to be captured. The sound 5-6" away and off-axis is different than it is on the grille, and it's also different han 5-6" away on-axis.

G.
 
SouthSIDE Glen said:
Of course it would be easier ;). It just wouldn't necessarily be right. The reason he is recommending the 57 be frenching the grille is because that is the sound to be captured. The sound 5-6" away and off-axis is different than it is on the grille, and it's also different han 5-6" away on-axis.

G.
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Can I get these two mics in phase while they are still 5-6 inches away from each other I guess is my question? and whats the real way to do it?
 
no, you can't. maybe you could at a few specific frequencies but unless the capsules are in the same place at the same time some frequencies are going to be out of phase, period. this means that if you pan them it will sound louder than when in mono, unfortunately, depending on the amount of phase and at what frequencies. the real way to do it is to use one mic.
 
DAS19 said:
Can I get these two mics in phase while they are still 5-6 inches away from each other I guess is my question? and whats the real way to do it?
Click to expand...
Technically speaking, no you cannot get all frequencies in exact phase at the same time under that setup. Different frequencies have different wavelengths, therefore the phase relationships for the different frequencies are different at any given distance between the microphones. You can adjust distances and/or track positions in a DAW timeline to bring dominant frequencies into sync, but sometimes at the potential cost of other frequencies.

But there are a hundred ways to skin this double-miking cat. There are also a score of variables involved that mean that what works for one situation does not necessarily work for another. For example, is your cab a 2x12, a 4x10, something else? That matters. Is it a Vox, Fender, Marshall or something else? That matters. What size is your room, where in the room is the cab placed, and is the room treated with bass traps? Those all matter as well. A mic placed a foot in front of a Fender DeVille 4x10 in an untreated room with a negative bass mode where the mic is placed is going to sound entirely different from a Marshall 1974 1x12 with the same mic in the same position in a room with bass traps in the corners.

The is why the real way to do it is to trust your ears and to experiment with mic techniques and positions. First of all, phase is not always the real life issue that it may look on screen. Second, one can have everything in perfect phase and sync and still have a lousy sound.

Personally if I'm going to double mic a git cab, I'm going to either use dual mics on the grille or the second mic is going to be, like Limit says, signifigantly further away from the cab than a few inches, more to get the room sound than anything else. But that's me.

Order a large pizza for you and a buddy and spend an evening playing with different mic positions and mic types and see what works for you. :)

G.
 
Yeah that large pizza idea is probably whats gonna happen I need to just find something that works and fuck the RIGHT WAY I mean I dont have bass traps. Maybe I will buy some cheap bass traps some guy sells a set of four on ebay for like 150.

I just realized though anyone trying to record with just a 57 is nuts. I couldnt get a decent sound with my life depended on it.
 
DAS19 said:
Yeah that large pizza idea is probably whats gonna happen I need to just find something that works and fuck the RIGHT WAY I mean I dont have bass traps. Maybe I will buy some cheap bass traps some guy sells a set of four on ebay for like 150.

I just realized though anyone trying to record with just a 57 is nuts. I couldnt get a decent sound with my life depended on it.
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hehehe.....I know what you're talking about...I was there once too.

I personally have taken a 'break' from the 57. I'm really digging my 421 and e609. I have also heard good things about the i5.

But it's there with the 57,..it is...moving the mic half an inch will effect the sound drastically.

SG said it...there are million ways to skin this cat. Decide what cat you're looking for (bright brit, deep metal, mid heavy rock) and move the mics till you hear it. If you can't,..maybe you need to change the guitar, or pickup..or sometimes just strings!

Good luck,..and above all...HAVE FUN!

-LIMiT
 
:( theres not really that many ways to skin a caT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!111111111111111111111111111111
 
DAS19 said:
I just realized though anyone trying to record with just a 57 is nuts. I couldnt get a decent sound with my life depended on it.
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You are incorrect sir. People who just record with a 57 just have better skills than you. I have many skilled guitar players going apeshit over the tones I capture with 1 sm57 on a standard Marshall 1960a. I know where you're coming from though, at one point I'd throw 4 mics on a cab and try to blend them and do all kind of crazy things until I actually took the time to learn how to get a great sound with one mic. Of course the player, guitar, and amp make a massive difference as well. What kind of amp are you using?
 
Phase trick

Here's another method of aligning the mic phases:

1. Unplug the guitar and leave the cable tip in contact with the input jack so that noise is generated (white or pink or whatever it is).

2. Fix the position of one of the mics (probably the close mic)

3. Flip the phase of one of the mics on its preamp.

4. Move the other (probably distant) mic around until the noise is minimized. Obviously you need to be listening to the output of both mics.

5. Flip phase back and record.
 
PhiloBeddoe said:
Here's another method of aligning the mic phases:

1. Unplug the guitar and leave the cable tip in contact with the input jack so that noise is generated (white or pink or whatever it is).

2. Fix the position of one of the mics (probably the close mic)

3. Flip the phase of one of the mics on its preamp.

4. Move the other (probably distant) mic around until the noise is minimized. Obviously you need to be listening to the output of both mics.

5. Flip phase back and record.
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hmm dont ahve preamps to flip the phase and it sounds easier then i bet it is but I appreciate your help. and to the other guy above yeah well a 1960a cab aint a rinky dink cab. im using a fender hotrod delux in a totally untreated normal bedroom so maybe thats why I cant get a good sound with a 57.
 
hmm dont ahve preamps to flip the phase and it sounds easier then i bet it is but I appreciate your help.
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If you are monitoring through your DAW, then you should be able to flip the phase in software also (cubase or protools or whatever).

It actually is very easy. You don't have to be an audio expert to hear the noise getting less and less. You can start with the two mics the same distance from the amp. They will probably pretty much be in phase at that point and the noise should be soft. Gradually move one mic away from the amp and you'll hear the noise get louder, then softer, then louder again. You will definitely notice a soft pocket.

That said, SouthSide is absolutely right that just because you have the mics 'in phase' does not mean you'll like what you hear.

Sometimes I think the 57 sucks too, but then I remember that a lot of great recordings have been made with them and in fact I've been happy with my own sounds from them in the past. Recently I've been toying with a Groove Tubes Convertible mic ($99) on guitar.

Anyway, best of luck.
 
I am just curious. What exactly does flipping a phase switch on a pre or in a DAW do?
 
DAS19 said:
Anyway, I am reading a tutorial on how to record an amp with two mics. This guy suggests to use a LDC about 5-6in away from the center cone of the amps speaker. He then says to place a 57 on the grill of the speaker off axis.
Dave
Click to expand...

i have used this technique and it works very well....however i put the LDC almost kissing the grille. i dont know why you are having the phase issues. go here http://www.ultimatemetal.com/forum/andy-sneap/274717-sneap-micing-techniques.html scroll down and you'll see and here examples of this. another thing is how are you going about mixing the two signals....start off with the 57 then bring up the LDC. you are gonna wanna cut some (not all ) of the bass from your cab...(not the eq of the daw or what ever mixing console you use) because the proximity effect will give you the bass you need. because they are two different types of mic one being dynamic and the other condencer and the 57 being off axis, that should take care of your phase issues.
 
baker_ said:
I am just curious. What exactly does flipping a phase switch on a pre or in a DAW do?
Click to expand...
It flips positive signal for negative signal and vice versa. Picture a waveforim in a DAW that travels upwards and then downwards. Flip the phase and the waveform will now go down and then up as if it were flipped upside down.

G.
 
A. record a little
B. see which track "happens" first
C. move that mic back
D. repeat

(the inverse works as well)
mmmmmmmmmmmmmmmm cheating with a daw.
 
scorpio01169 said:
i have used this technique and it works very well....however i put the LDC almost kissing the grille. i dont know why you are having the phase issues..
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LDC dont have the SPL to be that close to the grill. Its bad for the mic to do that. Thats why you arent getting any phase issues though. The mic hes using in the thread is a e609 and thats not a ldc its a dynamic.
 
giraffe said:
A. record a little
B. see which track "happens" first
C. move that mic back
D. repeat

(the inverse works as well)
mmmmmmmmmmmmmmmm cheating with a daw.
Click to expand...

Ive been trying something like that. Your way seems more pratical. Your recordings sound really good btw. lol
 
why is it bad for the ldc to be up close to the grille?.....i 've done it many times and no problems ever with my mic. i know he's using a 609.
 
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