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dbbubba · 16th January 2009

They way to check is to get a "phase checker" that puts out an impulse with one module that plug in at the beginning of your signal chain.
There is receiving device that looks at the impulse after it travels through your signal path and tells you if the phase is reversed.
They are not that expensive and Rolls Music makes a rather in-expensive ($150??) unit.

You actually DO want the speaker to move in an outward direction when a positive pulse is fed to it.
It is especially important when you deal with large diaphragm speakers like 18"s in a large sound system.
You want the initial impact of things like kick drums to push the speaker outward not only because it causes the initial wavefront of the sound to travel outward, but because you don't want the positive going and often stronger peaks to cause the voice coil to bottom out.

THERE IS A RIGHT WAY AND A WRONG WAY TO PHASE SPEAKERS!
I don't mean having the left and right speakers in phase with each other either.

In live situations we often use phased array subs to create a cardioid pattern of dispersion to focus and control the low end.
This set up requires very close attention to phase.
Also, many live system speakers have VERY specific phase settings.
This is especially true of newer design sub enclosures.

There really is no relative phase between mics, but you do need a starting point and you might as well have the wavefront moving in the proper direction.

It IS hard to look at waveforms and know what you are seeing unless you are really trained and really experienced at interpreting what you see.
I don't think you could really determine the phase of OHs that easily, but a kick drum is another matter.

Using your ears is important as the final test, but you would be wise to work hard to see that the positive pin is wired to the positive lead and phase stays consistent through any sound system.

16th January 2009	#16
dbbubba Banned Joined: Sep 2005 Posts: 7,099	They way to check is to get a "phase checker" that puts out an impulse with one module that plug in at the beginning of your signal chain. There is receiving device that looks at the impulse after it travels through your signal path and tells you if the phase is reversed. They are not that expensive and Rolls Music makes a rather in-expensive ($150??) unit. You actually DO want the speaker to move in an outward direction when a positive pulse is fed to it. It is especially important when you deal with large diaphragm speakers like 18"s in a large sound system. You want the initial impact of things like kick drums to push the speaker outward not only because it causes the initial wavefront of the sound to travel outward, but because you don't want the positive going and often stronger peaks to cause the voice coil to bottom out. THERE IS A RIGHT WAY AND A WRONG WAY TO PHASE SPEAKERS! I don't mean having the left and right speakers in phase with each other either. In live situations we often use phased array subs to create a cardioid pattern of dispersion to focus and control the low end. This set up requires very close attention to phase. Also, many live system speakers have VERY specific phase settings. This is especially true of newer design sub enclosures. There really is no relative phase between mics, but you do need a starting point and you might as well have the wavefront moving in the proper direction. It IS hard to look at waveforms and know what you are seeing unless you are really trained and really experienced at interpreting what you see. I don't think you could really determine the phase of OHs that easily, but a kick drum is another matter. Using your ears is important as the final test, but you would be wise to work hard to see that the positive pin is wired to the positive lead and phase stays consistent through any sound system.