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Title: Kik In/Kik Out: Reversing Polarity?
Post by: vunguyen on March 25, 2014, 07:27:50 PM
Do you reserve polarity between the 2 mics?
Thanks,
Vu
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Luke Robinson on March 25, 2014, 08:54:56 PM
I wouldn't, they are both experiencing a positive force from the head of the drum because they are on the same side of the batter head.

The case where you would reverse the polarity is when micing from opposite sides of the drum, Typically done when double mixing a snare drum. In this case the batter head is putting negative pressure on the top mic and positive pressure on the bottom mic on initial impact. so one of the two should be reversed in polarity.

Dave Rat does an exceptional job of explaining this in one of his many educational youtube videos...

http://www.youtube.com/watch?v=tPxxzswyoVg (http://www.youtube.com/watch?v=tPxxzswyoVg)

Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: David Simpson on March 25, 2014, 08:55:55 PM
No because you are still micing the same side of the head with both mics. That being said, there is nothing wrong with swapping polarity during sound check just to compare the sound, just in case there is a miswired cable or some other anomaly.

~Dave
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Jerome Malsack on March 26, 2014, 11:26:15 AM
here is an article on PRO Sound.

http://www.prosoundweb.com/article//not_so_mysterious_using_polarity_as_another_tool_for_optimizing_drum_sound/
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Ryan McLeod on March 26, 2014, 01:18:51 PM
Do you reserve polarity between the 2 mics?
Thanks,
Vu

FWIW, 99% of the time I end up inverting the polarity on the IN mic, and when I do I find I need pretty minimal channel EQ on either mic, assuming good placement & a reasonable drum/PA.

"If it sounds good, it is good" - experiment and find what works for you!

Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Mark McFarlane on March 26, 2014, 02:34:30 PM
I would reverse polarity on both mics, and possibly time delay the 'out' mic if I was being very anal and had time, assuming both mics are on the audience side of the head as opposed to the beater side. 

If you have drum monitors, sit on the drum throne and try reversing the kick mic, you may be amazed.
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Tim Weaver on March 27, 2014, 04:57:11 AM
I would reverse polarity on both mics, and possibly time delay the 'out' mic if I was being very anal and had time, assuming both mics are on the audience side of the head as opposed to the beater side. 

If you have drum monitors, sit on the drum throne and try reversing the kick mic, you may be amazed.


Wouldn't you delay the "in" mic instead?



Having 2 kick mics is no different than having any other 2 mics physically separated by a distance. There will be a phase (time) difference between the 2, but it may not be enough to warrant a 180 degree polarity swap.

Phase is time, time is phase, and it differs according to what frequency you are talking about. Polarity is simply 180 degrees of phase. There is positive or negative polarity, but phase is measured by degree.
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Mac Kerr on March 27, 2014, 09:35:03 AM

Wouldn't you delay the "in" mic instead?



Having 2 kick mics is no different than having any other 2 mics physically separated by a distance. There will be a phase (time) difference between the 2, but it may not be enough to warrant a 180 degree polarity swap.

Phase is time, time is phase, and it differs according to what frequency you are talking about. Polarity is simply 180 degrees of phase. There is positive or negative polarity, but phase is measured by degree.

The polarity probably depends on which head you are mic'ing the outside of. If the mic is on the beater side, the head moves away from the mic when struck, it moves toward the inside mic, that is a polarity difference. The time (phase) difference between them is maybe a foot. The wavelength of a 100Hz tone is 10', a foot isn't going to make a difference.

Even with the polarity difference between the beater mic and the inside mic you should make the judgement about polarity based on how you think it sounds.

Mac
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Mark McFarlane on March 27, 2014, 09:46:05 AM

Wouldn't you delay the "in" mic instead?

Yep, typing too fast.  Actually I proposed delay as hypothetical. I've never used 2 mics on the same side of the kick head, but I have mic'd kicks from several feet away for jazz trios, so the hypothetical 3 feet between mics would have warranted delaying the one inside the shell.

To judge the impact of the reverse polarity you need to try from the audience and from the drummers throne.  I was amazed at how much punchier and louder the kick became in the drum mons when reversing the polarity on the non-beater side kick mic.  I shouldn't have been surprised, the physics works.
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Jerome Malsack on March 27, 2014, 09:56:13 AM
In the small bar setup with FOH speakers if you draw a line between the two FOH and the Floor monitors are on the line facing the other direction you will also see the same polarity problem.   FOH push out and Monitor Push out but opposite directions.  Causing a Polarity issue.  Reversing the Monitors polarity makes the monitors lower registers audible and removes the polarity cancellation.   
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: TJ (Tom) Cornish on March 27, 2014, 10:01:54 AM
In the small bar setup with FOH speakers if you draw a line between the two FOH and the Floor monitors are on the line facing the other direction you will also see the same polarity problem.   FOH push out and Monitor Push out but opposite directions.  Causing a Polarity issue.  Reversing the Monitors polarity makes the monitors lower registers audible and removes the polarity cancellation.   
At what frequency?  Variable wavelength means that some frequencies will add, some will cancel.  It may indeed help at some frequencies, but I don't think this is axiomatic.
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Mac Kerr on March 27, 2014, 10:16:15 AM
In the small bar setup with FOH speakers if you draw a line between the two FOH and the Floor monitors are on the line facing the other direction you will also see the same polarity problem.   FOH push out and Monitor Push out but opposite directions.  Causing a Polarity issue.  Reversing the Monitors polarity makes the monitors lower registers audible and removes the polarity cancellation.   

No.

It does not matter what direction a speaker is facing, positive pressure is positive pressure. There will always be phase differences between multiple speakers on stage due to the arrival time offset caused by differing distances between the source and the listener, but that is not polarity, and back to back speakers do not cancel each other out.

Mac
Title: Re: Kik In/Kik Out: Reversing Polarity?
Post by: Keith Broughton on March 27, 2014, 02:35:01 PM
Yep, typing too fast.  Actually I proposed delay as hypothetical. I've never used 2 mics on the same side of the kick head, but I have mic'd kicks from several feet away for jazz trios, so the hypothetical 3 feet between mics would have warranted delaying the one inside the shell.

To judge the impact of the reverse polarity you need to try from the audience and from the drummers throne.  I was amazed at how much punchier and louder the kick became in the drum mons when reversing the polarity on the non-beater side kick mic.  I shouldn't have been surprised, the physics works.
Good point!
Gonna try it.