How To Mic A Guitar Amp | ASK A PRODUCER

Discussion in 'Studio & Stage' started by CoreyT, Feb 23, 2016.

  1. Chuckblues

    Chuckblues New Member

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    Les

    I'm willing to bet the cables that are 25 years old are much better quality than some you can get today !
     
  2. Michael_DK

    Michael_DK New Member

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    That's a self-fulfilling prophecy :) Any cable that has survived use for 25 years is bound to be better than some of the ones you can get today, simply due to natural selection :)
     
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  3. Dusty Chalk

    Dusty Chalk alberngruppenführer

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    So I recently added a second 4x10 to my 4x10 combo MDT, so basically 8x10 -- it sounds pretty freakin' sweet, but how would you even mic that?
     
  4. bodia

    bodia Authorities said.....best leave it.....unsolved

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    Duh, 8 mikes. No, no, 9. Gotta have a room mike too. :p
     
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  5. Michael_DK

    Michael_DK New Member

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    Some random thoughts about this :)

    First of all, doubling up on speakers probably means more volume. That might be PART of what you like. If they are stacked, it also means that you have the top cabinet closer to ear level, which means you're probably hearing more highs as well.

    Regarding mic'ing, always start with one mic to give you "max goodness" of what you like. In your case, you'd probably want a mic to pick up the "totality" of the sound (my interpretation). That means pulling back the mic from the cabinets compared to the video. Not necessarily as a "room mic", but just pulled back enough that the mic gets more of the speakers (if you were to place a mic directly on the cloth in front of one of the speakers, then you'd not hear much more than THAT particular speaker). It's possible that the ole standby SM57 wouldn't be the best choice for this application (conversely, it might work wonderfully. Only trying it out will tell). Maybe a condenser mic would be a good choice. Futz around with the placement until you hear what you like. The movements demonstrated in that video all apply, but on a grander scale. You can move it sideways, up and down, closer or farther, and angle it however you like. It's important to find a place where any room reflections add a pleasing dimension rather than an UN-pleasing one. Also important that you don't get unpleasant room resonances/modes (like if the low G is 10 dB louder than other notes etc etc). This might also involve moving the cab around to find the best spot.

    A suitable starting point might be simply to move around and find out where you hear the best sound overall - i.e. moving your body/head around, before setting up a mic. Then when you find a place where the sound is really good, and with a good balance between frequencies, set up a mic in the spot where your head is :).
    Then try recording that mic, and see if it still sounds good when you're not simultaneously playing the guitar. It's very different hearing something recorded vs. hearing it in the room while playing. Go back a couple of paragraphs to see what to listen for (reflections, resonances, etc etc.). Start with the mic pointing at the cab, then experiment with angling. Again, this is just a starting point - but you might as well start here if you're approaching it fresh.

    Moving a mic around that is placed a good distance from a speaker/cabinet (le's arbitrarily say three feet from the cab), you'll use much larger movements than what is demonstrated in that video. Moving a mic an inch will NOT give you the same drastic difference as when you're right up on the grill.

    Keep in mind that if you have no acoustical treatment (no, egg crates won't do it ;-)), you MIGHT not be able to get a very good sound.


    Anyway - once you find the optimal mic placement as best you can judge, then it's time to consider what (if anything) is lacking from that sound. But only if you actually DO find something missing from the sound :).
    That's when you break out mic number two. But once you have more than one mic, complexity will explode due to phasing issues. So really see if you can obtain what you want from just a single mic first!

    So let's say that the tone is perfect with a condenser three feet back in whatever position and whatever angle - BUT it's just missing some bite.
    You can get that by putting up a spot mic closer to one of the speakers.

    If you're really nit-picky, there will be a difference from speaker to speaker, so depending on level of OCD, you can try to listen to each speaker by placing your ear relatively close to each. DON'T BLOW OUT YOUR EARS. Actually, I'd advice against this if you're not a professional - it's most likely that any benefit you might get from this will be totally negated by lack of experience in general mic'ing technique and lack of room treatment etc etc. I'd just advise you to just pick one of the top speakers on general principle (potential comb filtering from reflections from the floor are less of an issue as you move further away from the floor).

    So, adding bite with the close mic.
    Since the first mic in this example gives you what you want in the bass department and with no lack of thump, you probably don't want this second mic too close to the speaker, as the proximity effect might make for overwhelming low end. So maybe three inches off the grill (arbitrary number time!). Then experiment like shown in the video with regards to placement, but with focus on "the kind of bite" that is lacking from the original mic. Find a good spot that gives you this.

    Adjust the levels of each mic to give you the blend that is the most pleasing.

    The issue is, now the mics are probably out of phase with each other. That's when the hunt begins.
    By adding the second mic, you all of a sudden lose the nice full low end of the original mic. What happened?
    Some frequencies are out of phase with each other, which cancels them out partly or completely. It's a crapshoot. Now you need to adjust the placements of the mic to get the best compromise - but without losing the overall goodness. It's kind of like chasing one's tail.

    In the end, maybe you'll just go back to square one, use just the first mic, but in a totally different position.

    There's a trick I've heard of, where you unplug the guitar cable from the amp, crank it up to max volume (or something like that), and listen to the hiss that is hopefully there. Now you flip the polarity on one of the mic channels (if you have this ability; otherwise this will obviously not work), and listen to the hiss from the combined mic signals. Then you move them around until the hiss gets as thin as possible, and then flip the polarity back. That should give you the thickest signal (less phase cancellations in the low frequencies). I've never tried it, so I don't know how well it works. I've always thought that in order for this to work, the "hiss" needs to have pretty low frequencies in there - otherwise you're not addressing the fullness of sound.

    Maybe it's easiest moving the far mic around, since smaller movements here will not alter the sound as drastically, but might still get you rid of the phase issues.


    Sorry for writing a novel. Hope something in here made sense. In conclusion: get as close as you possibly can using just one mic :)
     
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  6. Dusty Chalk

    Dusty Chalk alberngruppenführer

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    No, please don't apologize, I read and understood all of that. Thanks for sharing all those thoughts, I will give them a try.

    And no, I live in an apartment, and play late at night, so have a very natural tendency to play at the same volume. So same volume times 2ce as many speakers equals more linear.

    In my head, I was thinking that there might be a small amount of line array going on, combined with perhaps a little more bass from the bottom cabinet.
     
  7. LSchefman

    LSchefman Hears Tones

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    They're actually exactly the same Mogami Star Quad configuration cables they sell today.
     
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  8. LSchefman

    LSchefman Hears Tones

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    None of mine made 25 years ago by my tech have failed. Not one.
     
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  9. rugerpc

    rugerpc A♥ hoards guitars ♥A
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  10. bodia

    bodia Authorities said.....best leave it.....unsolved

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    Too harsh! He's obviously trying to pick up some ambient tones from sizzling tubes :D:po_O
     
  11. Dusty Chalk

    Dusty Chalk alberngruppenführer

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    The robot probably developed consciousness and is looking for a mate.o_O:eek::oops::D
     
  12. CoreyT

    CoreyT PRS Addiction

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    Phase Relationships Between Multiple Microphones | ASK A PRODUCER


     
  13. oneflightup

    oneflightup Flying.

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    Interesting thread, thanks for the link.

    I've found from my experience that there are as many ways to mic a guitar amp as your imagination allows you. Whether all will work for your particular: amp, room, desired sound, style of playing, etc etc, - is another question.
    I put together an article on recording electric guitars. Mainly just the basic points, but worth a read....

    At the end of the day, take plenty of time to experiment. Then when you've got the sound you like, that's when to start laying down takes.

    All the best with your recordings!

    Nick
    --------------
    One Flight Up Music Studios Sydney
     

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