I feel like I remember someone asking to be able to invert the polarity of a track and being frustrated that it wasn't readily available. I can't find that thread. But just now I noticed that the volume/pan plugin actually has a polarity switch. It's not so obvious but you can find it when the plugin is selected and the Control Panel is engorged. You can also find it in the Actions tab.
Am I going crazy? Didn't someone request it in the last year? How long has it been in a part of the volume/pan plugin?
Maybe it has something to do with polarity vs phase. The recommended fix was to load the native EQ which has a phase invert. Is there any functional difference between a polarity inversion and a 180 degree phase inversion?
Polarity
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- KVRian
- 524 posts since 16 Mar, 2017
Polarity is positive vs. negative - it flips the waveform upside down.
Phase is the starting point of a waveform which can also be though of as shifting the waveform through time. If you have a sine wave that begins playing at its zero crossing on the upward arc at the instant you press the key (or hit play), it is at "zero" phase - if it starts at the zero crossing on its downward arc, it is at "180 degree" phase. The concept of "phase inversion" would suggest playing the sound backwards, if it means anything at all?
Furthermore, you can shift phase by different amounts - it is not straight 180 or 0 degrees - but polarity can't be "partially" inverted. Either it is un-inverted or it is inverted; there are no intermediate levels of inversion.
Ordinarily, the effect of 180 degree phase *shift* and of inverted polarity will be identical for a "pure" waveform (sine, sawtooth, etc.), but when you start looking at a complex waveform which is composed of multiple frequencies of waveform overlapping each other, as would be typical of a recorded instrument or voice, this may not always be thought of in the same way. As there would be multiple frequencies of sound overlapping each other, trying to shift that waveform through time would in effect mean that to throw one of them 180 degrees out of phase, you would be throwing the others out of phase by different amounts (they wouldn't necessarily line up)... Unless you first break down the original sound into its component sine waves and work on them individually. On the other hand you can always invert the polarity of such a signal without any such complications.
Note that the perceived sound of a simple waveform which has been shifted 180 degrees out of phase or has been inverted in polarity will be identical to the unshifted/un-inverted sound that you started with when it is heard in isolation. The difference is in how it impacts the way that the signal is mixed with other sounds.
Phase is the starting point of a waveform which can also be though of as shifting the waveform through time. If you have a sine wave that begins playing at its zero crossing on the upward arc at the instant you press the key (or hit play), it is at "zero" phase - if it starts at the zero crossing on its downward arc, it is at "180 degree" phase. The concept of "phase inversion" would suggest playing the sound backwards, if it means anything at all?
Furthermore, you can shift phase by different amounts - it is not straight 180 or 0 degrees - but polarity can't be "partially" inverted. Either it is un-inverted or it is inverted; there are no intermediate levels of inversion.
Ordinarily, the effect of 180 degree phase *shift* and of inverted polarity will be identical for a "pure" waveform (sine, sawtooth, etc.), but when you start looking at a complex waveform which is composed of multiple frequencies of waveform overlapping each other, as would be typical of a recorded instrument or voice, this may not always be thought of in the same way. As there would be multiple frequencies of sound overlapping each other, trying to shift that waveform through time would in effect mean that to throw one of them 180 degrees out of phase, you would be throwing the others out of phase by different amounts (they wouldn't necessarily line up)... Unless you first break down the original sound into its component sine waves and work on them individually. On the other hand you can always invert the polarity of such a signal without any such complications.
Note that the perceived sound of a simple waveform which has been shifted 180 degrees out of phase or has been inverted in polarity will be identical to the unshifted/un-inverted sound that you started with when it is heard in isolation. The difference is in how it impacts the way that the signal is mixed with other sounds.
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- KVRAF
- Topic Starter
- 4891 posts since 3 Jan, 2003 from Vancouver
I wonder if the "Phase Invert" on the 4-band Equaliser is actually just a polarity invert. Sounds like it's a common thing for polarity invert to be labelled as phase invert.
Surely there must be consensus by now...
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- KVRian
- 1300 posts since 3 May, 2005 from Victoria, BC
I added fairly recently, but more than a year ago I think. 4 band is actually polarity, in general a lot of polarity buttons are mislabeled phase.
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- KVRAF
- Topic Starter
- 4891 posts since 3 Jan, 2003 from Vancouver
Waveform 9 has it. I don't know about 8 - I skipped that version.
Thank you for the clarification. The music industry has lots of mislabeled buttons, knobs, and more. Nice to know what it's actually doing even in cases like these where the results are essentially the same.FigBug wrote: Thu Jul 08, 2021 3:11 pm 4 band is actually polarity, in general a lot of polarity buttons are mislabeled phase.
Surely there must be consensus by now...
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- KVRian
- 524 posts since 16 Mar, 2017
Somewhat, but in the grand scheme of things, it's fairly tame compared to the stage lighting industry.pough wrote: Thu Jul 08, 2021 4:41 pm The music industry has lots of mislabeled buttons, knobs, and more.
Almost to a fault different lighting control consoles will use different terms to mean the same thing and the same terms to mean different things, and practically none of them match the DMX standards which define the protocols they use to communicate - then the lighting fixtures themselves are documented in a way that typically DOES match the DMX standards (even if they are from the same manufacturer as the consoles) which means they don't match any of the console documentation.