What is phasing and how the HELL do I get rid of it?? :p

  • Thread starter Thread starter WATYF
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WATYF

WATYF

...happier than you.
O.K.. so I put up a submission in the MP3 clinic... (you can listen to it for reference to my question) I then burned it to a CD and took it too a professional recording dude friend that I have... We listened to in on his expensive near-field monitors in his fancy-schmancy studio and the first words out of his mouth were... you've got some phasing going on. He then proceeded to explain to me (in technical jargon that I've already forgotten :p ) that phasing happens when wave forms conflict and cancel each other out, and that when you force two stereo channels to mono, you'll actually completely lose sound that is phased and blah blah blah... He showed me by pressing some button on his fancy-schmancy recording console that switched it all to mono.. and a bunch of the sound died out.

so.. my question is... why is my recording phased..?? What causes that..? Is my mic cheap,...? Are my cables bad...? Is it a crappy VST plugin I'm using??? Is my recording technique flawed?? Should I just sell all my gear and take up needlepoint??? :p

WATYF
 
Thanks for the info...

but what if I'm only using one mic..? :p

Maybe it's just that the separately recorded tracks are out of phase with each other... but I'm just not sure how to fix that (or even if you CAN fix that) or how to prevent it from happening again.

WATYF
 
Buy the very cheap Behringer Edison.
It's a stereo width enhancer, BUT even in bypass it's got a phase correlation meter which monitors the mono-compability of your mix.
It's about $100-150 I think.
Keep it turned on while you mix and keep the meter in the green.
 
umm the solution is to invert the sound wav. not sure how to do that on your console but in PC recording I just click a button called invert and it goes away. . . but always check in mono
 
OK.. I'll try those ideas.

but I still don't get what causes it... I mean... one day I'm walkin' along, mindin' my own business and all of a sudden,.. my recordings are phased???

Let's say I buy the Edison and see that while I'm recording, the meter buries itself in the red... well sure.. then I'll know I'm out of phase... but I still won't know how to actually do anything aboot it... :p

WATYF
 
WATYF,

What are you recording with? If you are using a PC based recording system you can isolate what tracks is causing the problem and invert the phase individually on each track. A piece of advice that floats around here is to alway mix in mono first. The after you have gotten the levels and Eq the way you want it, switch to a stereo mix and pan everything from there. Most consoles have a phase invert switch to cure these kinda of things, but if your doin PC's its almost as easy. Look under edit function if its PC, find a function called "invert", highlight the offending track,and invert it, listen to it in mono before you save the file. If you track in mono, it will be obvious that there is a problem even before you lay down the music.

Peace,
Dennis
 
Well.. I'm still a pathetic newbie... so I don't even know how to find out which track is phasing.. heck.. I didn't even know it was phasing till someone else told me... :p

I'll look into it to see if I have an "invert" option.. and I'll try to find out which track is causing the problem... wish me luck... :p

WATYF
 
FYI- If you are recording a source with a single mic there is no way there will be phase problems unless you add a really quick delay or obviously a phaser effect.

It this problem is rampant in your recordings even with one mic then make sure that you dont have some type of loop going on while recording. Sometimes if your monitor signal is getting looped back into the record channel it won't be loud enough to feedback but it will cause phase problems.

On the bright side worrying about mono compatability is a bit 'old school'. It is a good idea if you think there is any chance of the music being played on a mono PA system or something but interestingly enough Chessrock posted a comment from a popular engineer who worried more about surround sound compatability than mono.

Now you just need a surround system to check your mixes ;)
 
FYI- If you are recording a source with a single mic there is no way there will be phase problems unless you add a really quick delay or obviously a phaser effect.

It this problem is rampant in your recordings even with one mic then make sure that you dont have some type of loop going on while recording. Sometimes if your monitor signal is getting looped back into the record channel it won't be loud enough to feedback but it will cause phase problems.

On the bright side worrying about mono compatability is a bit 'old school'. It is a good idea if you think there is any chance of the music being played on a mono PA system or something but interestingly enough Chessrock posted a comment from a popular engineer who worried more about surround sound compatability than mono.

Now you just need a surround system to check your mixes ;)
 
Well... come to think of it.. it might be the way I'm recording my guitar... I use my cheesy SM58 to mic the sound hole and run that into track one of my mixer, and then run the pezio pick-up into track 2.. that way I have a "blend" of pick-up and acoustic sounds... (sort of like mimicing the blend pick-ups in Taylors.) So that might be causing it. When I get a good condensor mic, I won't be doing that anymore.

WATYF
 
WATYF said:
Well... come to think of it.. it might be the way I'm recording my guitar... I use my cheesy SM58 to mic the sound hole and run that into track one of my mixer, and then run the pezio pick-up into track 2.. that way I have a "blend" of pick-up and acoustic sounds...
WATYF
Click to expand...

AHA! NOW you tell us!!!

After misleading us with the "one mic" story (which, as Tex said, makes phasing pretty much a non-issue- because you need at least two tracks on a source for phasing...) you finally come clean!:D

What's happening is your pickup track is being recorded ahead of the mic track, and the difference between the two is dependent on how far the mic is from the guitar. As a result, you DO have true phasing.

On a computer system, this can be fixed by dragging one or the other track forward or back until they both match up. In an analog situation, you will need to put a delay on the pickup track (set 100% wet) and play with the delay time until it sounds the best. (Or you can do the math if you remember exactly how far the mic was (in feet) from the guitar and divide by 1100 to get your delay setting.)
 
Well.. I guess I won't be doing that anymore... :p

The problem is.. I was recording them both to one track... so I can't fix it (unfortunately)...

oh well.. live and learn.

WATYF
 
Maybe that's not the problem after all.

If you were recording them both to one track during the tracking process,then it stands to reason that you would have noticed the phasing yourself right after listening back to the track - it would have sounded very tinny and without body. Remember that one lone track cannot be in stereo; however, you mentioned that your friend switched his mixer (?) to mono and the signal nearly disappeared. I'd say there's something else going on that's causing your phasing problems.

Now if both of those signals you recorded were on separate TRACKS, then it would be easier to point fingers at the way you recorded and subsequently mixed the guitar signals. There's some confusion here still, though, because you said you RECORDED each signal (mic + piezo) to two different TRACKS of your mixer, when I think you meant you ROUTED the two signals through two separate CHANNELS of your mixer and then recorded those signals together on one track. Is that it, or am I way off? Just trying to help.

I could be wrong, of course, but something doesn't seem right here. Give it some thought...

Bruce in Korea
 
No.. you're right on... my lingo is still.. uh... lacking.. :p I thought I had said channels.... well.. I meant to say channels... :p

Yes... I route them separately to two channels.. and record them to one stereo track.. so you're right.. I guess that couldn't be the problem.. but.. what if I do use that method to record more than one guitar track..? I mean... the signal didn't totally disappear.. it just lost a lot when he went to mono.. anyway... I'm gonna get some new gear (yahoo) and change my recording technique anyway.. so that will prolly solve the problem... (hopefully)

WATYF
 
It still could make sense, assuming that you panned the mic and pickup channels to opposite sides and then recorded to a stereo track. That would explain why it changes when you collapse to mono.

You still may be able to fix it by splitting the stereo track into two mono tracks and then doing the shifting or delay that I talked about earlier.

If you aren't on a DAW that allows software splitting from stereo to two monos, just record the stereo track (panned hard L&R) onto two new mono tracks, and you're all set. If the original panning wasn't hard L&R, this solution may be imperfect, but it still may improve the sound.

By the way, if the guitar totally disappears in mono, it's likely that it may be a reversed polarity problem, not phase, on one of the tracks - and you may want to try flipping the polarity (on one of the tracks) first. This is usually caused by either a cable or (or occasionally some piece of gear) being miswired.
 
It doesn't totally disappear or anything.. you just lose "something" when it goes mono... (and no, I don't mean you lose that "stereo" sound :p )

I won't mess with it anymore... it was done on a scratch recording and I'll be using a different technique next time... thanks for all the help... now I know what not to do.

WATYF
 
btw, on micing acousitic guitars it is my understanding that you are not actually supposed to mic the hole but the body (about where the strings re-attach. . . and then again halfway up the neck. you really can't get very good micing positions at the hole because thats where your strumming hand is :) . . . but I'm a drummer so what do I know :)

peace
sam
zekthedeadcow@hotmail.com
http://www.track100.com
 
No.. that's correct... I don't mic right over the hole but rather right above the 12th-15th frets or so... (real close to the hole)

I'm also getting phasing in my vocals when I do BGV's... *sigh*.. why can't I record anything withoat phasing?? :p

WATYF
 
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