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Miking toms from the inside.. need to reverse phase?
Posted: Thu Sep 16, 2004 9:20 am
by run joe_ run_Archive
Miking a comedian from the inside....need to reverse phase?
Miking toms from the inside.. need to reverse phase?
Posted: Thu Sep 16, 2004 1:19 pm
by ebeam_Archive
Maybe it may just seem like semantics, but there is a big difference between phase and polarity. For the most part, what everyone here is talking about is reversing the *polarity*. This is what the switch incorrectly labelled 'phase' on your console is doing.....making all positive voltages negative and visa versa. Phase is a much more complicated beast. Flipping the polarity makes most sense when in a situation like micing a tom from the top and bottom. If you think about it, the intial attack is going away from the top mic, but toward the bottom mic... In the case of other multiple mic setups, the situation is more complicated and you might like the sound of the polarity reversed, but you'll probably have more luck dealing with the phase issues by changing relative mic placement or experimenting with a delay line.
Miking toms from the inside.. need to reverse phase?
Posted: Fri Sep 17, 2004 4:08 am
by olivier_Archive
180° phase shift = changing the polarity
Miking toms from the inside.. need to reverse phase?
Posted: Fri Sep 17, 2004 10:01 am
by ebeam_Archive
olivier wrote:180° phase shift = changing the polarity
This is not true and is reason why I said this may just seem like semantics. Phase shift means there is a difference in the time domain, polarity is independent of the time domain. They may seem like they are the same, but they aren't. Here is a decent article with illustrations:
http://www.digitalprosound.com/Htm/Tech ... reOne1.htm
Miking toms from the inside.. need to reverse phase?
Posted: Fri Sep 17, 2004 11:09 am
by olivier_Archive
of course you are right but it's very usual for people to speak about phase instead of polarity .. so i think the polarity button of the mixdesk is called phase because it help to fix phase problem ?
http://www.prosoundweb.com/studyhall/la ... _phase.pdf
Miking toms from the inside.. need to reverse phase?
Posted: Fri Sep 17, 2004 3:40 pm
by sndo_Archive
olivier wrote:180° phase shift = changing the polarity
Only if you're dealing with a sine wave of one particular frequency. If you changed to a different frequency you would also have to alter the amount of delay required to achieve a 180 degree shift.
But we don't work with sine waves. Most sounds are more complex than that. You could hone in on the resonant frequency and as long as the song had only one note you could phase shift the resonant frequny by 180, but all the overtones would spill over.