Difference between revisions of "Phase Cancellation"
(first ed.) |
(moved link to Phase to the bottom) |
||
| Line 1: | Line 1: | ||
Phase (cancellation, interference) | Phase (cancellation, interference) | ||
<!-- TODO resolve circular reference to category and this page --> | <!-- TODO resolve circular reference to category and this page --> | ||
| − | |||
| − | |||
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. | ||
| Line 11: | Line 9: | ||
[http://www.sfu.ca/sca/Manuals/ZAAPf/p/phase.html Phase at SFU]] | [http://www.sfu.ca/sca/Manuals/ZAAPf/p/phase.html Phase at SFU]] | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
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. | ||
| Line 33: | Line 24: | ||
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]] | ||
Revision as of 01:01, 23 August 2006
Phase (cancellation, interference)
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.
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
If you are suffering from some or all of these, you could be experiencing Phase Interference
- "Hot" and "cold" spots in the audience area
- Tonal coloration
- Poor speech intelligibility
- Lack of music clarity
- Poor gain-before-feedback
- Poor imaging
See: Practical Realities of Phase Interference
See: Phase