Phase Cancellation - Revision history

ST at 01:18, 30 August 2023

2023-08-30T01:18:24Z

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	# Poor imaging		# Poor imaging

	See: [http://www.livesoundint.com/archives/2003/july/phase/phase.php Practical Realities of Phase Interference]		See:
			There is an interesting visual presentation of [https://www.youtube.com/watch?v=D7aftTF--5w how phase cancellation occurs with two sound sources].

			[http://www.livesoundint.com/archives/2003/july/phase/phase.php Practical Realities of Phase Interference]

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ST at 17:14, 29 August 2023

2023-08-29T17:14:59Z

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			{{Bose Reviewed}}
	Phase (cancellation, interference)		Phase (cancellation, interference)
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ST: formatting noinclude

2007-10-06T10:52:36Z

formatting noinclude

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	See: [http://www.livesoundint.com/archives/2003/july/phase/phase.php Practical Realities of Phase Interference]		See: [http://www.livesoundint.com/archives/2003/july/phase/phase.php Practical Realities of Phase Interference]

			----
	See: [[:Category:Phase\|Phase]]		See: [[:Category:Phase\|Phase]]


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ST: formatting

2007-09-20T07:03:57Z

formatting

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	[[Image:PhaseIn.png]]		[[Image:PhaseIn.png]]


	Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in either a boost or cut in the overall level of the combined signal.		Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in either a boost or cut in the overall level of the combined signal.
	-- Phase at the Zen Audio Project		-- Phase at the Zen Audio Project

ST: Image:PhaseIn.png

2007-09-20T07:03:02Z

Image:PhaseIn.png

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	-->		-->

			[[Image:PhaseIn.png]]
	Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in either a boost or cut in the overall level of the combined signal.		Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in either a boost or cut in the overall level of the combined signal.
	-- Phase at the Zen Audio Project		-- Phase at the Zen Audio Project

ST: commented out dead links

2007-09-20T06:00:16Z

commented out dead links

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	=== Theoretical Discussion ===		=== Theoretical Discussion ===
	Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.		Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.
			<!-- dead link looking for replacement
	<html><br />		<html><br />
	<EMBED src="http://www.sfu.ca/sca/Manuals/ZAAPf/splash/phase_diagram.spl" width=490 height=174		<EMBED src="http://www.sfu.ca/sca/Manuals/ZAAPf/splash/phase_diagram.spl" width=490 height=174
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	The illustration above is from [http://www.sfu.ca/sca/Manuals/ZAAPf/p/phase.html Phase at SFU]]. Follow the link for a very interesting discussion about Phase.		The illustration above is from [http://www.sfu.ca/sca/Manuals/ZAAPf/p/phase.html Phase at SFU]]. Follow the link for a very interesting discussion about Phase.

			-->
	Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in either a boost or cut in the overall level of the combined signal.		Phase cancellation occurs when two signals of the same frequency are out of phase with each other resulting in either a boost or cut in the overall level of the combined signal.
	-- Phase at the Zen Audio Project		-- Phase at the Zen Audio Project

ST: /* Practical Note */ now done as inclusion {{:Phase Cancellation and the L1}}

2006-10-26T15:14:01Z

Practical Note: now done as inclusion {{:Phase Cancellation and the L1}}

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	~~== Practical Note ==~~		{{:Phase Cancellation and the L1}}
	"Finally, we have convinced ourselves that audible phase cancellation should not occur from two systems spaced more than about four feet apart. The combing is just too dense. " - Ken-at-Bose <ref>See: http://bose.infopop.cc/eve/forums/a/tpc/f/6806048934/m/7831003593?r=3291045593#3291045593 in
	{{~~Forum~~}}~~</ref>~~

ST: /* Theoretical Discussion */ formatting

2006-10-26T15:07:45Z

Theoretical Discussion: formatting

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	=== Theoretical Discussion ===		=== Theoretical Discussion ===
	Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.		Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.
	<html>		<html><br />
	<EMBED src="http://www.sfu.ca/sca/Manuals/ZAAPf/splash/phase_diagram.spl" width=490 height=174		<EMBED src="http://www.sfu.ca/sca/Manuals/ZAAPf/splash/phase_diagram.spl" width=490 height=174
	Loop="True" Play="True" BGColor="ffffff" Quality="Autohigh" Scale="Showall" SAlign="">		Loop="True" Play="True" BGColor="ffffff" Quality="Autohigh" Scale="Showall" SAlign="">

ST: /* Practical Note */

2006-10-26T15:06:49Z

Practical Note

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	== Practical Note ==		== Practical Note ==
	"Finally, we have convinced ourselves that audible phase cancellation should not occur from two systems spaced more than about four feet apart. The combing is just too dense~~. So all of that makes sense~~." - Ken-at-Bose <ref>See: http://bose.infopop.cc/eve/forums/a/tpc/f/6806048934/m/7831003593?r=3291045593#3291045593 in		"Finally, we have convinced ourselves that audible phase cancellation should not occur from two systems spaced more than about four feet apart. The combing is just too dense. " - Ken-at-Bose <ref>See: http://bose.infopop.cc/eve/forums/a/tpc/f/6806048934/m/7831003593?r=3291045593#3291045593 in
	{{Forum}}</ref>		{{Forum}}</ref>

ST: should not occur with units space more than about four feet apart

2006-10-26T15:06:19Z

should not occur with units space more than about four feet apart

← Older revision		Revision as of 15:06, 26 October 2006
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	<!-- TODO resolve circular reference to category and this page -->		<!-- TODO resolve circular reference to category and this page -->

			== Practical Note ==
			"Finally, we have convinced ourselves that audible phase cancellation should not occur from two systems spaced more than about four feet apart. The combing is just too dense. So all of that makes sense." - Ken-at-Bose <ref>See: http://bose.infopop.cc/eve/forums/a/tpc/f/6806048934/m/7831003593?r=3291045593#3291045593 in
			{{Forum}}</ref>


			=== Theoretical Discussion ===
	Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.		Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.
	<html>		<html>