Reversing phase?
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Posted on May 11, 2002 09:46 pm
Wight
Member Since: May 11, 2002
I have seen this mentioned in a couple of places - in the recording tips someone talked about miking a speaker cone at 2 and 8'o'clock and reversing the phase of one of the signals (or something like that) - also I have heard of miking the bottom head of the snare and reversing the phase. How do you reverse phase?? Is it worth doing?
Thanks
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WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
May 12, 2002 12:28 am I know some active DI boxes will do this electricaly and then there's using software to invert the waveform. What this will do is cause your playback speaker to respond to the signal in exact opsite phases. i.e. if you used two speakers on a drum hit with inverted phases one speaker will push out the other will pull in. This causes audio canclation like having stereo speakers out of phase. It works the most on low frequencies bass, keyboards, kick drum. Creates a real murkey sound or little sound at all. This is usually something folks want to correct say if a pickup on one instrument in a mix is inverted. Can't tell you why anyone would want to do this on purpose.
WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
May 12, 2002 12:36 am OOps!
It does make sense under a snare. If one mic is on top and the other is underneath they will react in opsite phases to a stick strike! Sorry, next time I will read better!
georgeContributor
Since: Apr 14, 2002
May 12, 2002 10:48 am Hi Wight. I'm afraid I'm the guilty party bringing up phase all the time. As Walt said, if two sources of the same sound are perfectly out of phase, you will hear nothing. The sounds will cancel each other out. This doesn't happen in the real world too often. However, if two sounds(stereo) are mostly out of phase, you'll loose most of the bass response. When I say check for phase, I'm saying make sure your not out of phase. I think the easiest way to flip phase is a) move one of the mics slightly, b) insert an inline phase reversal cylinder. these are only about 3 inches long, for about twenty bucks. AT and whirlwind make 'em. To make these yourself, just resolder a cord on one end, trading connections two and three. Good luck, George.
