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Thread: Micing amp with 2 mics. Phase issues.

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    Micing amp with 2 mics. Phase issues.

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    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

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    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
    Put the mic up and hit record, simple as that...

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    Quote Originally Posted by DAS19
    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?
    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.
    [SIZE=1][B][COLOR=DarkSlateBlue]Glen J. Stephan,
    SouthSIDE Multimedia Productions[/COLOR]
    [COLOR=DarkGreen]RECORDING RESOURCES AND INFO SITE:[/COLOR]
    [URL="www.independentrecording.net"][SIGPIC][/SIGPIC][/URL][/B][/SIZE]

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    Quote Originally Posted by SouthSIDE Glen
    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.
    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?

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    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.

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    Quote Originally Posted by DAS19
    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?
    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.
    [SIZE=1][B][COLOR=DarkSlateBlue]Glen J. Stephan,
    SouthSIDE Multimedia Productions[/COLOR]
    [COLOR=DarkGreen]RECORDING RESOURCES AND INFO SITE:[/COLOR]
    [URL="www.independentrecording.net"][SIGPIC][/SIGPIC][/URL][/B][/SIZE]

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    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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    Quote Originally Posted by DAS19
    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.


    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
    Put the mic up and hit record, simple as that...

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    theres not really that many ways to skin a caT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!111111111111111111111111111111

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    Quote Originally Posted by DAS19
    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.

    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?

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