phase and stereo image help

bluedaffy

bluedaffy

New member
I have a drum track that has 2 overhead drum tracks and I hard pan them and then flip the polarity on one, with it flipped the sound seems to be more centered, and unflipped it sounds way out in stereo. Does this mean one is closer to being in phase and one is not? Or does the stereo image not diagnose something like that?
 
bluedaffy said:
I have a drum track that has 2 overhead drum tracks and I hard pan them and then flip the polarity on one,
Click to expand...

Why's that?
Phase and polarity are two different things.

In a traditional overhead setup both mics are above the kit so polarity is left alone.(edit - they are kept the same as eachother)

Phase is a time/distance thing.
The floor tom will hit the left mic before it hits the right mic.
The hi hat will hit the right mic before it hits the left mic.
Everything that isn't equidistant from the two mics will be recorded with a phase 'issue'. (That's why it's stereo!)
Some people measure from kick and snare to make sure they are not only perfectly central in the stereo image, but also strong and full sounding.

Flipping polarity of a mic like you describe will probably cancel kick and snare to some degree.
 
Last edited:
Actually, I can't think of a time, where I have not reversed the 'polarity' of both overhead mics, when recording a kit. Never one of them alone.

I am not sure how the '3 to 1' rule applies here, but the low end punch of the kit always sounds better IME, with the panned 2-mic overheads, flipped.

We have had conversation around here on this topic, but not sure what thread. In any case, it is a typical procedure for me.
 
Last edited:
Steenamaroo said:
It doesn't. OHs are for a stereo image which doesn't exist without phase discrepancies.
Click to expand...

I am curious then, why it works. The conversation in the thread I mentioned, kinda fizzed out. I think it ended with, 'yeah, it works'.....or maybe a 'see if it works for you'...

Either way, it works for me. YMMV. :)
 
I've just heard that flipping the phase on one side of a stereo track can cause the sound to become a wider stereo image, I'm just curious if there is a relationship between width and out of phaseness lol.
 
Well, I am not sure I am the one to answer this, as I am more of a 'do it and see/what works for me' kind of guy, but I would never place something out of 'phase' for purposes of increasing a stereo image. That is a side effect of 'stereo wideners', or maybe how they work. Either way, not something to use in huge amounts. Not at all in my opinion. I have had times, where a stereo image enhancer worked well for a situation, but never, ever for drums.

I should probably ask, how wide do you need, farther than panned full left and right? Anything more, is an effect that is fooling your brain. There are likely side effects. Whether they are good/bad for a particular situation, is for you to decide.

You should probably look into the difference between polarity, and phase.
 
bluedaffy said:
I've just heard that flipping the phase on one side of a stereo track can cause the sound to become a wider stereo image, I'm just curious if there is a relationship between width and out of phaseness lol.
Click to expand...

Well yes true on both counts -sort of, so lets thin this out.
For starts take a mono image and flip one side. (pardon if you know and done this..) It is a very noticeable but weird effect- not like just wider' or true stereo at all.

Since we don't know quite what's going on on the O/H tracks how about you first pan them both dead center.
Now listen to one and the other by there self -That will be our base line' as to how the kit' sounds totally in phase (because.. one mic = one point in space and from only one point' in time (discounting room effects for a moment) = 'in phase.
Now bring in the other O/H -both still center panned.. and flip one or the other.

This (panned center) gives the best view (and/or worst case depending on how this turns out :D ..of your combined phase condition and their effects.

Is one combination totally more out'o whack, or looses way more tone than the other state?

Could one of the mics been recorded phase.. :p oops, polarity flipped?

If it was a spread pair there will always be tone' shifts -phase effects, due to arrival time differences from the various points on the kit.
Our job is just finding nice sounding combinations ;)
 
bluedaffy said:
I have a drum track that has 2 overhead drum tracks and I hard pan them and then flip the polarity on one, with it flipped the sound seems to be more centered, and unflipped it sounds way out in stereo. Does this mean one is closer to being in phase and one is not? Or does the stereo image not diagnose something like that?
Click to expand...

This sounds more like you've got a cable with pins 2 and 3 swapped on one end.

How are your overheads positioned?
 
The 3to1 rule does not apply to stereo Mic techniques at all. It reduces phase cancellation through isolation of the signals. Having a Mic three times farther away than another one will make the signal in the farther one 9db quieter than the close one. that is the minimum amount of difference it takes for you not to hear the comb filtering. The 3to1 rule doesn't work at all if the gain structure of both Mic signal paths aren't the same. However, if you simply make one Mic at least 9db quieter than the other one, it doesn't matter where you put the Mic.

The 3to1 rule was made up to isolate two different sound sources in the same room, not two Mics on the same source.
 
I might be mis-understanding what some people are saying in this thread, because a lor of it doesn't make sense.

First of all, a mic can't be in or out of phase alone. It can only be in or out of phase with another mic. Phase being in or out is always IN RELATION to another mic.It would be impossible to ever make a statement like "My mic is out of phase"....."out of phase" with what?

Second, if you flip the polarity on just one overhead, this shouldn't make it sound better. If it does, there's something wonky going on with your set-up and/or mic placement.

Third, I've never heard of anyone flipping the polarity on both overheads. That's a new one for me. I've flipped the polarity on a snare or a kik for it be more coherent with my overheads, but never the other way around.
 
Last edited:
RAMI said:
I might be mis-understanding what some people are saying in this thread, because a lor of it doesn't make sense.

First of all, a mic can't be in or out of phase alone. It can only be in or out of phase with another mic. Phase being in or out is always IN RELATION to another mic.It would be impossible to ever make a statement like "My micis out of phase"....."out of phase" with what?

Second, if you flip the polarity on just one overhead, this shouldn't make it sound better. If it does, there's something wonky going on with your set-up and/or mic placement.

Third, I've never heard of anyone flipping the polarity on both overheads. That's a new one for me. I've flipped the polarity on a snare or a kik for it be more coherent with my overheads, but never the other way around.
Click to expand...

Yes x 1,000,000,000 to all of that.
 
Jimmys69- I dont want a wide stereo image, I was asking purely because I was curious about 'if the stereo image sounds very wide when hard panned, does that mean that it is more out of phase than when the phase is flipped on one and the sound becomes more centered?'

Also- I'm pretty sure that I know the difference between phase and polarity, I just made a mistake in my first post. The polarity in the most basic newbie sense is the direction the waveform travels, like if a snare drum was struck and the transient of the wave goes up first, that means it's positive right?

RAMI- Depending on the individual drum polarities and if the sound is purer, I will flip both negative overheads to match the positive kick rather than flip the kick from positive to negative to match the overheads. The idea that the speakers initially 'push out' for something deep and powerful like a kick drum makes more sense to me than sucking in. ... Might be confusing but that's my thought process as to why sometime I flip the overheads to match the kick instead of flipping the kick to match the overheads.
 
bluedaffy said:
JiRAMI- Depending on the individual drum polarities and if the sound is purer, I will flip both negative overheads to match the positive kick rather than flip the kick from positive to negative to match the overheads. The idea that the speakers initially 'push out' for something deep and powerful like a kick drum makes more sense to me than sucking in. ... Might be confusing but that's my thought process as to why sometime I flip the overheads to match the kick instead of flipping the kick to match the overheads.
Click to expand...
I don't think it works that way. But I guess you're not really causing any harm either so , whatever. It don't matter to me. I never flip phase or polarity, etc....I just line up my tracks so that they're all in phase with each other without having to flip anything.
 
The problem with getting too wrapped up in polarity and phase on drums is that different parts of a drum head are often out of phase with or have inverted polarity from other parts of the same drum head. The phase and polarity of a signal can vary with mic placement on the drum. It's certainly a good thing to have a concept of what's going on but you can't be too literal. Your ears are the final arbiter of what sounds good.

You asked if the stereo image can help diagnose phase/polarity issues. It can. In this case I think it's telling you that you have a miswired cable or other pin 2-3 swap on one of the overhead mics. But it would help to know how the mics are placed: X-Y, spaced overheads up high, low over the cymbals or whatever.
 
RAMI said:
I don't think it works that way. But I guess you're not really causing any harm either so , whatever. It don't matter to me. I never flip phase or polarity, etc....I just line up my tracks so that they're all in phase with each other without having to flip anything.
Click to expand...
Course, that only works if they're the same absolute polarity to begin with. If - for whatever reason - the first transient of the kick goes up in one mic and down in another, then nudging to line up the upswings just causes more phase mess.

And that's what it sounds like is going on in the OP. Provided that I have never heard nor seen the two tracks in question, it does generally seem like one of the mics had polarity opposite the other when first recorded. But this "stereoness" is NOT a great way to determine these things. Better to listen specifically to what happens to the kick and maybe snare when the polarity flips. Does the kick disappear, or lose a lot of its low end thump, in one position compared to the other?

The best way to tell the relative polarity of the two would be to zoom in on the waveforms and see whether they both swing the same direction at (or very close to) the same time.

Absolute polarity is completely arbitrary. Yes, I can see where it "makes sense" that a kick drum should "push" first, but that's only true if you're in front of the kit. Leads to those arguments of audience perspective vs drummer perspective... But more important is the question whether the difference is noticeable. The answer to that question is hotly debated but I for one am thoroughly convinced that it is a non-issue. Doesn't hurt anything, though, and if it satisfied your personal version of OCD, then go for it!
 
ashcat_lt said:
Course, that only works if they're the same absolute polarity to begin with. If - for whatever reason - the first transient of the kick goes up in one mic and down in another, then nudging to line up the upswings just causes more phase mess.
Click to expand...
Yes, but I said I line them up. If one waveform is going up while the other is going down, then I obviously didn't line them up, did I.
 
RAMI said:
Yes, but I said I line them up. If one waveform is going up while the other is going down, then I obviously didn't line them up, did I.
Click to expand...
Yes, but if you lined them up without flip polarity of one then you've pushed them even further away from each other.
 
You must log in or register to reply here.
Back
Top