Members sweet Posted August 22, 2005 Members Share Posted August 22, 2005 Can someone give me, or refer me to, a primer on phase? I understand that the signal is a wave form, and that phase reversal basically flips the form upsidedown. What I can't get my head around is why/when you need to do this, or what causes "bad phase". I think I read that if you keep two mics 3x from eachother as from the sound source, you should be ok. IOW, what does a phase problem sound like and what produces a phase problem. Is it only applicable when using one mic? eg, if I record guitar with one cab, one mic, do I have to worry when I layer another take? BTW, thanks to everyone for all the great (free) advice and thanks to Phil for a great forum. I read daily but don't post much. Link to comment Share on other sites More sharing options...
Members rhythminmind Posted August 22, 2005 Members Share Posted August 22, 2005 if you use 2 or more mics on the same source is when you really need to worry about it.. if they are 100% out of phase they cancel each other out. (silence).. but if there only somewhat out of phase it will start canceling part of the wave/frequencies (bad news).. 2 different guitar takes panned in general will be fine... if you have out of phase tracks zoom up on your wav files in your DAW you can make adjustments if needed.. or flip the phase.. you should play with this to get a grasp of it.. take one of your tracks, duplicate it and pan both center, invert the phase on one of them. you shouldnt hear anything. now slowly nudge one of the tracks and you will start to hear a "phasey" effect... Link to comment Share on other sites More sharing options...
Members Will Chen Posted August 22, 2005 Members Share Posted August 22, 2005 While phase is an important aspect of sound, to fully understand it you need to have a basic grasp of acoustical physics. While you might not be able to define it, you should be able to hear it as a filtering effect when no effects have been applied. This is a result of frequency cancelation. Out of phase is as you stated when one waveform is the mirror reflection (opposite) of another. If we're dealing with pure sine waves of the same frequency, the summed out of phase signal will be complete silence. What we refer to a phase is basically the overlapping of wave forms so phase can not be an issue when using only 1 mic but can become an issue when that one source is mixed with other similiar sources. Generally speaking, if you mix in a second take without moving the mic you don't need to worry about it. Link to comment Share on other sites More sharing options...
Members sweet Posted August 23, 2005 Author Members Share Posted August 23, 2005 Thanks guys!!! Originally posted by rhythminmind you should play with this to get a grasp of it.. take one of your tracks, duplicate it and pan both center, invert the phase on one of them. you shouldnt hear anything. now slowly nudge one of the tracks and you will start to hear a "phasey" effect... I'll do that! Link to comment Share on other sites More sharing options...
Members digwhisper Posted August 23, 2005 Members Share Posted August 23, 2005 Okay here's a dumb question that is only slightly off topic. How do you reverse the phase on a track using Pro Tools LE? Link to comment Share on other sites More sharing options...
Members rhythminmind Posted August 23, 2005 Members Share Posted August 23, 2005 audiosuite or plugins.. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted August 23, 2005 Share Posted August 23, 2005 Originally posted by BechtelChris Okay here's a dumb question that is only slightly off topic. How do you reverse the phase on a track using Pro Tools LE? And if all you want to do is flip the phase, the least CPU hungry plug in that does it is probably the stock Digidesign "Trim" plug in. Leave the trim gain unchanged and just hit the phase invert ("circle with the diagonal line through it") button - you can see that symbol in the top picture that rhythminmind posted. BTW, good job on the graphics RIM. Link to comment Share on other sites More sharing options...
Members digwhisper Posted August 23, 2005 Members Share Posted August 23, 2005 Thanks gentlemen! I am loving this new forum, lots of positive attitude and info flowing! Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted August 23, 2005 Share Posted August 23, 2005 Thanks Chris! Link to comment Share on other sites More sharing options...
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