Absolute Polarity in Mastering
Old 29th June 2009
  #1
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Absolute Polarity in Mastering

Playing around with polarity on some asymmetrical waveforms made me think about absolute polarity in mastering.

I was trying to explain the phenomenon to a student and failed miserably in explaining how to detect it (I can explain why), except that 1) it can only be determined by ear, and 2) you need to confirm that it's not a monitoring issue first.

How often do you guys check and switch for the best polarity setting in mastering? I use the word "best" intentionally, since it's not always a case of simply being "different".

On some tracks it makes almost no difference, while it can make a huge difference on other tracks, e.g. a dance track with a saw bass or whatever.
Old 29th June 2009
  #2
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The problem is that you have no controll over the polarity outside your own domains.
By that reason I don´t pay any attention to absolute phase.
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Old 29th June 2009
  #3
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i predict this thread will go like this

i can hear absolute phase ,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't.

when it should be like this

i can hear absolute phase,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes i can,no you can't,yes you can.
etc

but yes i can ...sometimes, some projects

so i leave the files as is to make up for the other times when i hear no difference

but i have absolute phase aligned every studio bit and bob we have with a emt phase gun system... !
and i have found a bunch of stuff leaves the factory with no regard to absolute phase
go figure ..?
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Old 30th June 2009
  #4
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I check it but never change it unless one way is obviously better and not simply different. That happens less than once a year.
Old 30th June 2009
  #5
Mastering
 

Quote:
Originally Posted by Lagerfeldt View Post
Playing around with polarity on some asymmetrical waveforms made me think about absolute polarity in mastering.

I was trying to explain the phenomenon to a student and failed miserably in explaining how to detect it (I can explain why), except that 1) it can only be determined by ear, and 2) you need to confirm that it's not a monitoring issue first.

How often do you guys check and switch for the best polarity setting in mastering? I use the word "best" intentionally, since it's not always a case of simply being "different".

On some tracks it makes almost no difference, while it can make a huge difference on other tracks, e.g. a dance track with a saw bass or whatever.
I should bother more often but I keep forgetting! It is the last thing that I bother with. My celebrated Lipinski speakers are incorrect absolute polarity! It's a deep dark secret, I haven't even told Andrew as his English is rather poor. Anyway, they aren't going to re-engineer all their speakers. So they're incompatible with everyone else's, especially everyone else's subwoofer, or at least remember to correct the polarity.

Once I discovered the Lipinski polarity was incorrect, I reversed all the speaker leads.

Now, can you hear it? Lagerfeldt is absolutely right. Sometimes it matters a lot. But it is not my highest priority to fix absolute polarity in mastering, it's even less important to me than dither :-). I save that consideration for my audiophile clients.

BK
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Old 30th June 2009
  #6
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Maybe I should provide an audio example so everybody can judge for themselves?

Obviously a simple test with a saw waveform will persuade even the most pig headed person that absolute phase is for real. A mastering example would be great though.

But as some have already mentioned, not a huge issue generally speaking in mastering.

Quote:
Originally Posted by Bob Olhsson View Post
I check it but never change it unless one way is obviously better and not simply different. That happens less than once a year.
Right, that's where I stand too.

Quote:
Originally Posted by philip View Post
The problem is that you have no controll over the polarity outside your own domains.
By that reason I don´t pay any attention to absolute phase.
I also don't have control over a lot of other things outside my studio, but that doesn't stop me from trying to address those issues when mastering.
Old 30th June 2009
  #7
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Quote:
Originally Posted by Lagerfeldt View Post
Maybe I should provide an audio example so everybody can judge for themselves?

Obviously a simple test with a saw waveform will persuade even the most pig headed person that absolute phase is for real. A mastering example would be great though.

But as some have already mentioned, not a huge issue generally speaking in mastering.


Right, that's where I stand too.


I also don't have control over a lot of other things outside my studio, but that doesn't stop me from trying to address those issues when mastering.
no, you don't get the idea about polarity, it has nothing to do with mastering, it's all about monitoring.
If you hear a big difference in polarity you should really check your pre and poweramps so that they are up to specs.
Old 30th June 2009
  #8
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Quote:
Originally Posted by philip View Post
no, you don't get the idea about polarity, it has nothing to do with mastering, it's all about monitoring.
If you hear a big difference in polarity you should really check your pre and poweramps so that they are up to specs.
According to the psychoacoustics, a lot more happens with a positive pressure change than a negative change. Makes sense as most real events starts with a high pressure zone. Going from equilibrium to a negative pressure is somewhat hard to do in nature.

The effect is not that subtle. The Lavry DA10 is wired pin 3 hot. Unlike just about anything it can connect to. Both me and a friend discovered that the hard way.. "Why is it most all records sounds better with inverted polarity?" "RTFM.." "Doh!" :D

Real sounds are more convincing and many synthesized sounds have more punch when the polarity is right.

I do check it at times, but not always. Mostly if things seems right balance wise, but still doesn't have the right snap to it. If I'm in doubt as to what's the real direction, checking the transient edge of a drum hit or other short transient event is often revealing.
Old 30th June 2009
  #9
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Quote:
Originally Posted by Lupo View Post
According to the psychoacoustics, a lot more happens with a positive pressure change than a negative change. Makes sense as most real events starts with a high pressure zone. Going from equilibrium to a negative pressure is somewhat hard to do in nature.

The effect is not that subtle. The Lavry DA10 is wired pin 3 hot. Unlike just about anything it can connect to. Both me and a friend discovered that the hard way.. "Why is it most all records sounds better with inverted polarity?" "RTFM.." "Doh!" :D

Real sounds are more convincing and many synthesized sounds have more punch when the polarity is right.

I do check it at times, but not always. Mostly if things seems right balance wise, but still doesn't have the right snap to it. If I'm in doubt as to what's the real direction, checking the transient edge of a drum hit or other short transient event is often revealing.
yes, but you still have no controll of the polarity, it might sound better inhouse but speakers can change the phase several thousand degrees so you don't know whats "right" anyway.
If you want to listen to absolute phase it's easy:
make a squarewave @ 123hz - make another one with phase flipped. compare, what do you hear? (you can lowpass the files if you like)
Old 30th June 2009
  #10
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Quote:
Originally Posted by philip View Post
no, you don't get the idea about polarity, it has nothing to do with mastering, it's all about monitoring.
Au contraire.

Try reading up on absolute polarity then get back to me with an apology for being so rude ;-)

Seriously, my point is that all things equal there will be a need to check for this also.

Quote:
If you hear a big difference in polarity you should really check your pre and poweramps so that they are up to specs.
Let's get back on the subject and not discuss something that has been proven and is easily testable.

The question is not whether absolutely polarity exists or not, or if it can be hear or not. It can.

The question was how often we as mastering engineers check for this during the mastering process.

PS. It's called "absolute polarity", not "absolute phase", though it is indeed flipped 180 degrees.
Old 30th June 2009
  #11
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The square wave doesn't work as an example. It's symmetrical and repeating waveform, both polarites gives the same end result. Try something with a more transient nature, like this drum track:

andreaslupo_snurresprett_snippet 1644.wav

Since the ear is mostly deaf to negative transient events, flipping the polarity sounds like a transient softener on this track. Transient on, transient offs. The snare gets a lisping quality to it with the polarity inverted and the overall sound is duller.

Inspecting the leading the edge of the drum waveform confirms that the initial blast is moving in the positive direction. If this track had been sent to mastering as an inverted file, flipping the polarity would be a very quick and easy way to get more punch out of the track.
Old 30th June 2009
  #12
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Quote:
Originally Posted by Lagerfeldt View Post
Au contraire.

Try reading up on absolute polarity then get back to me with an apology for being so rude ;-)

Seriously, my point is that all things equal there will be a need to check for this also.


Let's get back on the subject and not discuss something that has been proven and is easily testable.

The question is not whether absolutely polarity exists or not, or if it can be hear or not. It can.

The question was how often we as mastering engineers check for this during the mastering process.

PS. It's called "absolute polarity", not "absolute phase", though it is indeed flipped 180 degrees.

you don't really get it do you? read my posts again. It doesn't matter what you prefer as a reference as absolute phase, no one else is going to be able to repeat.
(if you don't have the exact setup as in your masteringstudio)
Old 30th June 2009
  #13
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Quote:
Originally Posted by philip View Post
no, you don't get the idea about polarity, it has nothing to do with mastering, it's all about monitoring.
If you hear a big difference in polarity you should really check your pre and poweramps so that they are up to specs.
Sorry, Philip, that statement makes absolutely no sense and you have produced confused logic. Yes, polarity does have to do with monitoring, but once you have calibrated and checked the polarity of your monitoring you then have a reference system which the MASTERING ENGINEER can use to check the polarity of the source. So yes, absolute polarity "has to do" with mastering!

Then, in your second sentence you have implied that somehow if you check your pre and power amps then differences in polarity will no longer be so audible? Huh? What exactly would you check?

Well, yes, non-linear distortion somewhere in a system (in a loudspeaker gap?) can make one polarity sound better than another, it is a variable, but it is not always the cause. I wouldn't know how to begin diagnosing that variable, anyway. Does anyone else technical here have a way?

Anyway, we have no control over the consumer's system, but for those consumers who care and who have set their systems correctly, we DO have control, so absolute polarity should matter, when it makes an audible difference. It's just that it's a relatively small phenomenon, some loudspeaker systems are more sensitive to it than others, it matters on some material more than others, and consequently, as mastering engineers we mostly have better things to do.

Now as long as we are discussing minutia, I'll give my observations.

1) My ears are not that sensitive to absolute polarity, it's not that important to me.

2) The literature says that absolute polarity matters most in the bass region. Telarc always made sure that their bass drums would produce an outward-going woofer for most impact. In a careful test with a live trumpet and a Blumlein microphone at RCA studios, I produced an absolute polarity test that's on one of the Chesky test records. When the polarity is wrong, this trumpet appears to be somewhat farther from the microphone. It was quite remarkable, and implies that absolute polarity errors can affect mixes. Does it make the vocalist recede? Not to my ears, but I haven't done a definitive test.

3) If a vocalist sings into a mike and listens live with headphones, incorrect absolute polarity of the headphones can sound disastrous. But this is not because the absolute polarity matters, but rather because the relative polarity between the bone conduction and what comes through the headphones produces a cancellation effect if the polarity of the headphones is wrong. So don't confuse absolute polarity issues with relative ones!

4) Supposedly, Eggleston speakers are very sensitive to absolute polarity differences, according to Bob Ludwig and Peter McGrath

I could go on, and tell you there is even a cult of absolute polarity among certain audiophiles. I have better things to worry about :-).


Next topic?

BK
Old 30th June 2009
  #14
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Quote:
Originally Posted by Lupo View Post
The square wave doesn't work as an example. It's symmetrical and repeating waveform, both polarites gives the same end result. Try something with a more transient nature, like this drum track:

Attachment 126936

Since the ear is mostly deaf to negative transient events, flipping the polarity sounds like a transient softener on this track. Transient on, transient offs. The snare gets a lisping quality to it with the polarity inverted and the overall sound is duller.

Inspecting the leading the edge of the drum waveform confirms that the initial blast is moving in the positive direction. If this track had been sent to mastering as an inverted file, flipping the polarity would be a very quick and easy way to get more punch out of the track.
sorry my mistake: saw
Old 30th June 2009
  #15
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Originally Posted by bob katz View Post
Sorry, Philip, that statement makes absolutely no sense and you have produced confused logic. Yes, polarity does have to do with monitoring, but once you have calibrated and checked the polarity of your monitoring you then have a reference system you can use to check the polarity of the source. Then, in your second sentence you have implied that somehow if you check your pre and power amps then differences in polarity will no longer be so audible? Huh? What exactly would you check?

Well, yes, non-linear distortion somewhere in a system (in a loudspeaker gap?) can make one polarity sound better than another, it is a variable, but it is not always the cause. I wouldn't know how to begin diagnosing that variable, anyway. Does anyone else technical here have a way?

Anyway, we have no control over the consumer's system, but for those consumers who care and who have set their systems correctly, we DO have control, so absolute polarity should matter, when it makes an audible difference. It's just that it's a relatively small phenomenon, some loudspeaker systems are more sensitive to it than others, it matters on some material more than others, and consequently, as mastering engineers we mostly have better things to do.

BK
well, lot's of times when you "hear" absolute phase it is caused by inferior equipment.
No consumer (or me or you for that matter) can set their system correct cause there is no correct in practical terms.
Maybe in theory but most loudspeakers ****s the phase up so much it doesn't matter.
Old 30th June 2009
  #16
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Quote:
Originally Posted by philip View Post
you don't really get it do you?
Again, I believe you are the one not "getting it".

...ready for that apology anytime soon?

Now it's time to eat some Thai food and get out in the sun here in CPH. Cheers!
Old 30th June 2009
  #17
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Originally Posted by Lagerfeldt View Post
Again, I believe you are the one not "getting it".

...ready for that apology anytime soon?

Now it's time to eat some Thai food and get out in the sun here in CPH. Cheers!
yes, I don't get it explain please.
Old 30th June 2009
  #18
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I believe Bob Katz spent 2.334 characters (not counting spaces) doing just that 5 posts above this one.

I doubt I will do a better job than him, so I'll leave it there.
Old 30th June 2009
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Quote:
Originally Posted by Lagerfeldt View Post
I believe Bob Katz spent 2.334 characters (not counting spaces) doing just that 5 posts above this one.

I doubt I will do a better job than him, so I'll leave it there.

Bob did not say anything of interest. So haven't you. Please explain to me how absolute polarity can be judged and used in mastering.
Please let me know how you define the "right" polarity. Please explain how you know what polarity the artist intended.
Lets start there, I'm REALLY looking forward to your answers.
Old 30th June 2009
  #20
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Quote:
Originally Posted by philip View Post
Bob did not say anything of interest. So haven't you.
Though I'm an experienced forum user and I know not to feed the troll, I can't help it.

So here goes:

Quote:
Please explain to me how absolute polarity can be judged and used in mastering.
Switch polarity, listen, decide which one sounds best, and leave it there.

Quote:
Please let me know how you define the "right" polarity.
The one that sounds best on the given material.

Quote:
Please explain how you know what polarity the artist intended.
The one the track originally came with would be a good guess, but if I decide it sounds better with switched polarity, that's what I'm going to do.
Old 30th June 2009
  #21
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Quote:
Originally Posted by Lagerfeldt View Post
Though I'm an experienced forum user and I know not to feed the troll, I can't help it.

So here goes:


Switch polarity, listen, decide which one sounds best, and leave it there.


The one that sounds best on the given material.


The one the track originally came with would be a good guess, but if I decide it sounds better with switched polarity, that's what I'm going to do.
ok, then it´s a non issue for mastering per se, but if you work better with the phase inverted, good for you.
Old 30th June 2009
  #22
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Originally Posted by philip View Post
ok, then it´s a non issue for mastering per se, but if you work better with the phase inverted, good for you.
inversion = direction

direction = polarity

phase = time
Old 30th June 2009
  #23
Ignoring the rather impolite righteousness of a certain poster, it seems like a simple concept:

If one way sounds better, then that is probably the best way to go. How else do we make decisions about treating source material? Why would using the absolute polarity that sounds best be any different from EQ or anything else we normally do?

(Please ignore if this is not "interesting" to you!)
Old 30th June 2009
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Originally Posted by prolearts View Post
Ignoring the rather impolite righteousness of a certain poster, it seems like a simple concept:

If one way sounds better, then that is probably the best way to go. How else do we make decisions about treating source material? Why would using the absolute polarity that sounds best be any different from EQ or anything else we normally do?

(Please ignore if this is not "interesting" to you!)
no thats fine if you like to work that way. But the problem is there is no right or wrong with polarity, so even if you change polarity and it sounds better to you, this does not mean the polarity is "right". This does not mean it will sound right to any one else in any given situation. so flipping the phase could be fun, but it's not mastering.
Old 30th June 2009
  #25
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Originally Posted by TranscendingM View Post
inversion = direction

direction = polarity

phase = time
ah sorry, english is not my first language. I think you get my point anyway.
Old 30th June 2009
  #26
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Quote:
Originally Posted by philip View Post
no thats fine if you like to work that way. But the problem is there is no right or wrong with polarity, so even if you change polarity and it sounds better to you, this does not mean the polarity is "right". This does not mean it will sound right to any one else in any given situation. so flipping the phase could be fun, but it's not mastering.

philip I think in general when it comes to aesthetic quality, sure "right" and "wrong" doesn't really apply most of the time. However, if you do indeed get a softer transient let's say with polarity differences then if a metal or rock piece for example calls for "punchiness" then one would surmise that if inversing polarity helps attain the punchiness then it is part of mastering. As was mentioned before, isn't any technique that brings us the results we desire part of the process?
Old 30th June 2009
  #27
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Originally Posted by TranscendingM View Post
philip I think in general when it comes to aesthetic quality, sure "right" and "wrong" doesn't really apply most of the time. However, if you do indeed get a softer transient let's say with polarity differences then if a metal or rock piece for example calls for "punchiness" then one would surmise that if inversing polarity helps attain the punchiness then it is part of mastering. As was mentioned before, isn't any technique that brings us the results we desire part of the process?
yes of course! if there was a standard about polarity* it would be the first thing to check. I'm not reasoning if it's wrong or not, I just say it does not have any practical meaning today. It´s a really interesting phenomen that I put a lot of time and effort to understand.

*even in the loudspeaker domain that is.
Old 30th June 2009
  #28
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Quote:
Originally Posted by philip View Post
no thats fine if you like to work that way. But the problem is there is no right or wrong with polarity, so even if you change polarity and it sounds better to you, this does not mean the polarity is "right". This does not mean it will sound right to any one else in any given situation. so flipping the phase could be fun, but it's not mastering.
If ANY mastering decision could clearly be classified to be either right or wrong, you really wouldn't need an engineer.
Old 30th June 2009
  #29
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Quote:
Originally Posted by philip View Post
yes of course! if there was a standard about polarity* it would be the first thing to check. I'm not reasoning if it's wrong or not, I just say it does not have any practical meaning today. It´s a really interesting phenomen that I put a lot of time and effort to understand.

*even in the loudspeaker domain that is.

Sure, but protocol or not, it's audio related and just as much part of mastering as EQ, compression, etc. is.
Old 30th June 2009
  #30
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There is a polarity standard if the wish is to recreate a real event.

When something strikes something else, a positive pressure rises. The leading transient edge is, for most sounds, positive. The ear is for the most part only listening to the positive side of sound, ignoring the negative stuff. Having a polarity inversion means that the sound is robbed of it's impact. The initial transient contains quite a lot of interesting information.

"Triple blind" test: AES E-Library: Proofs of an Absolute Polarity
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