using two mics and phase issues?
- Thread starter DankStar
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GuitarStv
Sock Market Trader
Re: using two mics and phase issues?
The best that I can think of for you is the 3:1 rule: Keep the mics at least three times as far away from the item that you're micing as they are far away from each other. So if your amp (or the object that you're recording) is 3 feet away, then keep the mics within one foot of each other.
The best that I can think of for you is the 3:1 rule: Keep the mics at least three times as far away from the item that you're micing as they are far away from each other. So if your amp (or the object that you're recording) is 3 feet away, then keep the mics within one foot of each other.
DankStar
Her Little Mojo Minion
Re: using two mics and phase issues?
ah, that's a good rule of thumb. I'll try that.
ah, that's a good rule of thumb. I'll try that.
frankfalbo
In Fluence Y'all
Re: using two mics and phase issues?
That is a great rule. Phasing issues aren't always resolved with a phase reversal either. Sometimes you're "in between" and a phase reversal of one mic simply shifts the awkward phasing sound to different frequencies. In other words, if you're going to be out of phase, you'd better be near 180 degrees out or else the phase reversal on the board isn't 100% effective.
On the other hand, that's only assuming you don't want ANY phasing coloration at all. Most recordings you hear have some phasing issues, and I create most of my guitar tones with three speaker cabinets. Undoubtedly if each cab signal was analyzed, I would have some frequency combing. And I don't care because it sounds good.
That is a great rule. Phasing issues aren't always resolved with a phase reversal either. Sometimes you're "in between" and a phase reversal of one mic simply shifts the awkward phasing sound to different frequencies. In other words, if you're going to be out of phase, you'd better be near 180 degrees out or else the phase reversal on the board isn't 100% effective.
On the other hand, that's only assuming you don't want ANY phasing coloration at all. Most recordings you hear have some phasing issues, and I create most of my guitar tones with three speaker cabinets. Undoubtedly if each cab signal was analyzed, I would have some frequency combing. And I don't care because it sounds good.
vinterland
New member
Re: using two mics and phase issues?
If phase is a problem you'll typically be able to hear it as it will sound really thin and lifeless. Otherwise, stick to the 3:1 rule as mentioned above and if you like what you hear then don't worry about it.
If phase is a problem you'll typically be able to hear it as it will sound really thin and lifeless. Otherwise, stick to the 3:1 rule as mentioned above and if you like what you hear then don't worry about it.
muttonchopsrule
New member
Re: using two mics and phase issues?
what type of device are you recording to? if you're recording to a computer, then depending on the software you can just place the mics where each mic sounds best, regardless of their phase relationship, then nudge the track over after it's been recorded if necessary.
if you aren't able to do that, you can also solve this with a delay unit if you have one. set the delay to 100% wet (so you only hear the delayed sound) and set the delay time according to how far apart the mic's are. sound travels roughly 1130 feet per second, which rounds down to roughly 1 foot per milisecond. so if your mic's are 10 feet apart, delay the signal of the closer mic by 10 miliseconds and that should get you in phase, or at least dang close.
what type of device are you recording to? if you're recording to a computer, then depending on the software you can just place the mics where each mic sounds best, regardless of their phase relationship, then nudge the track over after it's been recorded if necessary.
if you aren't able to do that, you can also solve this with a delay unit if you have one. set the delay to 100% wet (so you only hear the delayed sound) and set the delay time according to how far apart the mic's are. sound travels roughly 1130 feet per second, which rounds down to roughly 1 foot per milisecond. so if your mic's are 10 feet apart, delay the signal of the closer mic by 10 miliseconds and that should get you in phase, or at least dang close.
J Moose
New member
Re: using two mics and phase issues?
That's some pretty mediocre advice there...
Works in theory & all that...but not too well in practice since it totally ignores all practical & concrete AE conventions.
Plus it leaves the potential for things to get "weird" after the fact...like having 'yer guitars (or whatever the source might be) disappear in mono. Now before anyone can even question if mono is still valid...MTV & VH1 still wind up being mono in about 70% of American homes and that Myspace player collapses the signal somethin' FEARCE!
Anywhoo...
The "best" method here is STILL the old-skool way.
Get 'yer first mic up and make sure that sounds good on it's own, that it's capturing some sorta usable tone and stands up on it's own merit.
Add the second mic while listening to the first mic...but listen in one-speaker mono. So ya wanna pan both mics either hard right or left while you sweep #2 (or 3, or 4) around to find the magik spot for the rest of the mics.
It's of course...MUCH easier to do this if you've got someone else to move mics around while you play & listen to what's happening while the mics are being moved.
What 'yer gonna wanna listen for is a fullness or otherwise "pleasing" tone that when both mics are up.
If it sounds like there's a Phase 90 in there that's stuck half-way through it's sweep....MASSIVE frequency cancellation...that's kinda bad! LOL
Unless you want that kinda tone anyway. Sometimes that's entirely valid, but usually not.
That's some pretty mediocre advice there...
Works in theory & all that...but not too well in practice since it totally ignores all practical & concrete AE conventions.
Plus it leaves the potential for things to get "weird" after the fact...like having 'yer guitars (or whatever the source might be) disappear in mono. Now before anyone can even question if mono is still valid...MTV & VH1 still wind up being mono in about 70% of American homes and that Myspace player collapses the signal somethin' FEARCE!
Anywhoo...
The "best" method here is STILL the old-skool way.
Get 'yer first mic up and make sure that sounds good on it's own, that it's capturing some sorta usable tone and stands up on it's own merit.
Add the second mic while listening to the first mic...but listen in one-speaker mono. So ya wanna pan both mics either hard right or left while you sweep #2 (or 3, or 4) around to find the magik spot for the rest of the mics.
It's of course...MUCH easier to do this if you've got someone else to move mics around while you play & listen to what's happening while the mics are being moved.
What 'yer gonna wanna listen for is a fullness or otherwise "pleasing" tone that when both mics are up.
If it sounds like there's a Phase 90 in there that's stuck half-way through it's sweep....MASSIVE frequency cancellation...that's kinda bad! LOL
Unless you want that kinda tone anyway. Sometimes that's entirely valid, but usually not.
muttonchopsrule
New member
Re: using two mics and phase issues?
it's worked out fine for me in the past without anything screwing up when played back in mono.
it's worked out fine for me in the past without anything screwing up when played back in mono.
J Moose
New member
Re: using two mics and phase issues?
Hmmm.
Yes. Well...
No offense intended man...but I'm sure that at the age of 19 you've spent many many hours of 'yer life in rooms that are acoustically treated & reveal the utmost of subtle differences in sound & therefore know EXACTLY what 'yer doing when you shift audio in both frequency & time domain...
Yah.
Bending physics...it kinda works.
Try it my way a couple times & see if it doesn't radically alter your world.
Try it on ANY instrument...it's complete magik on drums.
One-speaker mono rules!
Then open it back up to stereo & do all 'yer whacky panning & whatnot....but at least get the picture of the source...what 'yer recording captured well.
Think of it like focusing a camera lens.
That's a 421 & 57 focused on one spot of the top left speaker in a '70s Marshall w/ original Greenbacks.
I had the 57 up & the guitar player wasn't diggin' my first pick but we both liked the 57...swap that out for a 421...
Get 'em as close together as 'ya can, move the mics back & forth a hair at a time until the capsules come into alignment. The body of the 421 is slightly ahead of the 57 because the capsule of the 421 is a bit farther back.
But anywhoo...what I do is bring 'em up to equal gain and then invert the polarity (NOT phase! a common mistake!) on one mic and listen to how much is cancelling out.
From there, ya have someone play guitar while someone else slowly sweeps one mic forward & backward until you get as MUCH cancellation as you can get or, find the least/most offensive sound & lock the mic stands down.
Flip the phase back to normal & fire away!
Hmmm.
Yes. Well...
No offense intended man...but I'm sure that at the age of 19 you've spent many many hours of 'yer life in rooms that are acoustically treated & reveal the utmost of subtle differences in sound & therefore know EXACTLY what 'yer doing when you shift audio in both frequency & time domain...
Yah.
Bending physics...it kinda works.
Try it my way a couple times & see if it doesn't radically alter your world.
Try it on ANY instrument...it's complete magik on drums.
One-speaker mono rules!
Then open it back up to stereo & do all 'yer whacky panning & whatnot....but at least get the picture of the source...what 'yer recording captured well.
Think of it like focusing a camera lens.
That's a 421 & 57 focused on one spot of the top left speaker in a '70s Marshall w/ original Greenbacks.
I had the 57 up & the guitar player wasn't diggin' my first pick but we both liked the 57...swap that out for a 421...
Get 'em as close together as 'ya can, move the mics back & forth a hair at a time until the capsules come into alignment. The body of the 421 is slightly ahead of the 57 because the capsule of the 421 is a bit farther back.
But anywhoo...what I do is bring 'em up to equal gain and then invert the polarity (NOT phase! a common mistake!) on one mic and listen to how much is cancelling out.
From there, ya have someone play guitar while someone else slowly sweeps one mic forward & backward until you get as MUCH cancellation as you can get or, find the least/most offensive sound & lock the mic stands down.
Flip the phase back to normal & fire away!
Virtual Kevorkian
New member
Re: using two mics and phase issues?
Moose, Michael Wagener uses that same technique to get mic's on a guitar cabinet in phase, but he says he pans them far left/right in his headphones, and flips the phase (not polarity) on one - then get's the sound directly in the center of his headphones, or at least where it cancels out the most. Then, flips the phase back to normal, and records away.
Is this technically wrong, in that case? I can't imagine Michael Wagener doing something rudimentary incorrectly, but you never know!
Moose, Michael Wagener uses that same technique to get mic's on a guitar cabinet in phase, but he says he pans them far left/right in his headphones, and flips the phase (not polarity) on one - then get's the sound directly in the center of his headphones, or at least where it cancels out the most. Then, flips the phase back to normal, and records away.
Is this technically wrong, in that case? I can't imagine Michael Wagener doing something rudimentary incorrectly, but you never know!
muttonchopsrule
New member
Re: using two mics and phase issues?
J Moose:
i've read a lot of your posts and definitely look up to your knowledge when it comes to audio and still consider myself an amateur my all means.
but say you've got two very very very similar signals (like the same source mic'd with two different mic's) on two different tracks on the computer in protools or nuendo, or whatever software, and one is slightly out of phase with the other due to one of the mic's being further away from the source...moving one track back or forward in time will help to get them in phase when the stereo mix leaves the speakers. it may not be ideal and as you pointed out it's best to solve any phase problems in the tracking stage. but it'll still work.
like i said before, i know you're a ton more experienced than i am, but if you're saying that it isn't an acceptable solution in the in the professional world of audio, then i'd just like to ask you why. i'm not trying oppose what you're saying, just curious is all. i'm the kind of dude that likes to know why things behave as they do, not just accept the fact that something happens and that's it. i've got a pretty good understanding of how phase relationships work acoustically and electrically, but if nudging tracks in the software is an unacceptable method for solving phase issues, how come?
J Moose:
i've read a lot of your posts and definitely look up to your knowledge when it comes to audio and still consider myself an amateur my all means.
but say you've got two very very very similar signals (like the same source mic'd with two different mic's) on two different tracks on the computer in protools or nuendo, or whatever software, and one is slightly out of phase with the other due to one of the mic's being further away from the source...moving one track back or forward in time will help to get them in phase when the stereo mix leaves the speakers. it may not be ideal and as you pointed out it's best to solve any phase problems in the tracking stage. but it'll still work.
like i said before, i know you're a ton more experienced than i am, but if you're saying that it isn't an acceptable solution in the in the professional world of audio, then i'd just like to ask you why. i'm not trying oppose what you're saying, just curious is all. i'm the kind of dude that likes to know why things behave as they do, not just accept the fact that something happens and that's it. i've got a pretty good understanding of how phase relationships work acoustically and electrically, but if nudging tracks in the software is an unacceptable method for solving phase issues, how come?
Virtual Kevorkian
New member
Re: using two mics and phase issues?
I actually don't see it as un-acceptable at all - Andy Sneap, James Murphy, and Colin Richardson do it to take care of phase issues, particularly snare/kick and OH's.
I actually don't see it as un-acceptable at all - Andy Sneap, James Murphy, and Colin Richardson do it to take care of phase issues, particularly snare/kick and OH's.
muttonchopsrule
New member
Re: using two mics and phase issues?
word.
i've done it before on drum overheads, and it ended up really thickening up the snare sound, since there was some phase cancellation between the snare mic and the OH's.
i've also done it on guitars. i put a 57 right on the speaker and a KSM27 (may not have been the very best mic choice, but hey, i'm a broke college kid
) a few feet back, like this
obviously there was some phase cancellation going on, but i moved the track that the KSM27 was on back a little bit after it was tracked, and the result was that the guitars sounded a lot bigger than just with the 57.
word.
i've done it before on drum overheads, and it ended up really thickening up the snare sound, since there was some phase cancellation between the snare mic and the OH's.
i've also done it on guitars. i put a 57 right on the speaker and a KSM27 (may not have been the very best mic choice, but hey, i'm a broke college kid
) a few feet back, like this
obviously there was some phase cancellation going on, but i moved the track that the KSM27 was on back a little bit after it was tracked, and the result was that the guitars sounded a lot bigger than just with the 57.
J Moose
New member
Re: using two mics and phase issues?
Hola! Been really slammed in 'mix' for the last few days, got a couple minutes to breathe my own air while I'm waiting for the client to arrive...
Yeah...'ya know...I always try not to say anything bad about someone else's work & Michael's a buddy and all that...BUT...
That Kings X record (Ogre Tones) he did...while having some great songs (and I REALLY dig Kings X!) is a complete sonic trainwreck.
Sounds big & bad, SUPER wide in stereo...but sum it to mono?!
TOTALLY different world. Guitars are GONE.
So are the backing vocals & a lot of other stuff.
It's like listening to a WHOLE other mix.
Bizzare.
Gotta be (in not just my opinion) the worst sounding Kings X record ever. Thankfully the songs stand on their own two feet but for overall tone & listening pleasure, gimmie "Dogman" or "Faith Hope Love."
I'm probably gonna have to make this a multi-parter since I gotta jet in about three minutes...but in the next part I'll get to meat of it...back to 11th grade physics...how sound "works."
Talk about the differences between phase, polarity, amplitude, frequency response & time domain...how they're all pretty much related like kissing cousains but ARE NOT the same things and therefore easily confused and how that can wreak sonic mayhem on 'yer rekkids.
See the above Kings X record for an example.
Peace.
Hola! Been really slammed in 'mix' for the last few days, got a couple minutes to breathe my own air while I'm waiting for the client to arrive...
Yeah...'ya know...I always try not to say anything bad about someone else's work & Michael's a buddy and all that...BUT...
That Kings X record (Ogre Tones) he did...while having some great songs (and I REALLY dig Kings X!) is a complete sonic trainwreck.
Sounds big & bad, SUPER wide in stereo...but sum it to mono?!
TOTALLY different world. Guitars are GONE.
So are the backing vocals & a lot of other stuff.
It's like listening to a WHOLE other mix.
Bizzare.
Gotta be (in not just my opinion) the worst sounding Kings X record ever. Thankfully the songs stand on their own two feet but for overall tone & listening pleasure, gimmie "Dogman" or "Faith Hope Love."
I'm probably gonna have to make this a multi-parter since I gotta jet in about three minutes...but in the next part I'll get to meat of it...back to 11th grade physics...how sound "works."
Talk about the differences between phase, polarity, amplitude, frequency response & time domain...how they're all pretty much related like kissing cousains but ARE NOT the same things and therefore easily confused and how that can wreak sonic mayhem on 'yer rekkids.
See the above Kings X record for an example.
Peace.
ratherdashing
Kablamminator
Re: using two mics and phase issues?
Moose, I'm in your camp when it comes to phasing. I'm all about getting the best possible sound to "tape" during the recording as opposed to fixing a crappy recording in the mixing stage. It drives me INSANE when I have two out of phase signals, so I always make sure my mics are placed perfectly before recording. It's not very hard to check phase (the easiest and most reliable method is already described above), and as long as some dumbass doesn't move your mics you only have to do it once.
When I recorded guitar tracks for my old band's EP I had a Mesa DC-3 with a line out. I ran the line out into one channel, a close-mic'd SM57 into another channel, and a drum overhead mic (can't remember which one) about 5 feet back into a third channel. I spent about half an hour moving the mics around one at a time until the phase was dead on, then mixed the three sources down to mono. The result was an absolutely MASSIVE guitar sound, especially when double tracked. The three signals really complemented each other.
Moose, I'm in your camp when it comes to phasing. I'm all about getting the best possible sound to "tape" during the recording as opposed to fixing a crappy recording in the mixing stage. It drives me INSANE when I have two out of phase signals, so I always make sure my mics are placed perfectly before recording. It's not very hard to check phase (the easiest and most reliable method is already described above), and as long as some dumbass doesn't move your mics you only have to do it once.
When I recorded guitar tracks for my old band's EP I had a Mesa DC-3 with a line out. I ran the line out into one channel, a close-mic'd SM57 into another channel, and a drum overhead mic (can't remember which one) about 5 feet back into a third channel. I spent about half an hour moving the mics around one at a time until the phase was dead on, then mixed the three sources down to mono. The result was an absolutely MASSIVE guitar sound, especially when double tracked. The three signals really complemented each other.
Stevo
Tonus Maximus Pacificas
Re: using two mics and phase issues?
Some good advice above and I will add a suggestion from my own experience.
I have had good luck using a close mic and an ambience mic. The close mic stand is centered in front of the speaker but the mic points somewhere around the edge of the cone. The ambience mic takes some placement tweaking. I have used ambience mics that ranged from about 5 feet to 15 feet from the amp. That distance perspective creates a natural delay, which you can mix later.
Sometimes I use 2 ambience mics: one pointing in from the left side of the amp and one from the right. I have done that with drums too - not as the exclusive mics but to add natural ambience in stereo. It takes a while to tweak the placements but as stated above, I agree that it is best to get the best sound possible while recording it.
Some good advice above and I will add a suggestion from my own experience.
I have had good luck using a close mic and an ambience mic. The close mic stand is centered in front of the speaker but the mic points somewhere around the edge of the cone. The ambience mic takes some placement tweaking. I have used ambience mics that ranged from about 5 feet to 15 feet from the amp. That distance perspective creates a natural delay, which you can mix later.
Sometimes I use 2 ambience mics: one pointing in from the left side of the amp and one from the right. I have done that with drums too - not as the exclusive mics but to add natural ambience in stereo. It takes a while to tweak the placements but as stated above, I agree that it is best to get the best sound possible while recording it.
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