What is a phase switch


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powerage225
12-30-2006, 02:23 AM
So you can wire a humbucker in series, parallel, coil-tap it, but what does the phase wiring do?

Dirk Gently
12-30-2006, 02:27 AM
Phase switching changes the way the soundwaves produced by two sound sources interact with another. Out-of-phase sounds thin and nasal.

powerage225
12-30-2006, 02:42 AM
thanks
can anyone give me an example of a song where it is used
right now I'm guessing the intros of Mastodon's "Island" or (ugh) "I believe in a thing called love"

TinTin8
12-30-2006, 03:28 AM
ive heard that frusanite (sp) ... of RHCP usues Out-of-Phase Pups ... so yeah

Dirk Gently
12-30-2006, 03:28 AM
^ Anyone with a stock Strat that uses the 2 and 4 positions uses out-of-phase pickups.

TinTin8
12-30-2006, 03:51 AM
^ Anyone with a stock Strat that uses the 2 and 4 positions uses out-of-phase pickups.
i dont know if thats right ... 2 & 4 dont seem to be thin a nasely

That_Pink_Queen
12-30-2006, 05:16 AM
Dirk Gently is very wrong. Out of phase means that the pickups are wired in reverse, so the output that matches between the two pickups is canceled out. What you hear is the difference in tone between the two coils---which is typically thin and trebly.

Dirk Gently
12-30-2006, 11:36 AM
^ I am not wrong. "Phase" has to do with how soundwaves relate to one another. Your explanation doesn't include WHAT phase actually is or HOW a pickup wired in reverse would cancel out one wired with standard polarity, just how in a guitar phase shifting might occur. That is not really a definition at all, then. It's akin to someone saying "Define 'chair.'" and you point and say "that." They cancel each other out because the crests and valleys of the oscillating soundwaves are in, basically, opposing synchronicity with one another. This is also why sound phase is always described in degrees.

http://img141.imageshack.us/img141/5209/phasems3.png

This is taken from Wikipedia:

Phase shift
Phase shifting describes relative phase shift in superimposing waves. Waves may be of electromagnetic (light, RF), acoustic (sound) or other nature. By superposing waves using different phase shifts the waves can add to (0 shift = "in phase") or cancel out each other (180).

A phase shift is also a difference or change in the initial phase...Thus, a shift in time is equivalent to a phase shift. Conversely, a change in the initial phase is tantamount to a shift in time.

Phase difference

Phase difference is similar to phase shift, but more likely to be applied in the context of two signals, particularly when neither is a standard reference. Two waves that have the same frequency and different initial phases, have a phase difference that is constant (independent of t). So it is referred to simply as the phase difference, rather than the initial phase difference or the phase-shift difference. When the phase difference (modulo 2π) is zero, the waves are said to be in phase with each other. Otherwise, they are out of phase with each other. The terms are also commonly hyphenated, and used as an adjective: "The out-of-phase signal caused distortion." If the phase difference is 180 degrees (π radians), then the two signals are said to be in antiphase. And if their peak amplitudes are equal, their sum is zero at all values of time, t.

In phase this is analogous to two athletes running around a race track at the same speed and direction, side by side. They pass a point on the track together (simultaneously). Out of phase this is analogous to two athletes running around a race track at the same speed and direction but starting at different positions on the track. They pass a point at different instants in time. But the time difference (phase difference) between them is a constant same for every pass since they are at the same speed and in the same direction. If they were at different speeds, this would be analogous to two waves of different frequencies. Then, the phase (angle) difference measurement would be meaningless and void.

As far as Fender switching goes, if you have a Reverse-Wound, Reverse-Polarity middle pickup, the hum-cancelling 2 and 4 positions also produce an out-of-phase sound. And if you want to hear a great recorded example of this sound, check out "Sultans of Swing" by Dire Straits.

I'll accept your forthcoming apology. :p:

Wyld Stallyn
12-30-2006, 11:56 AM
I thought TPQ was right - phase shouldn't actually be used to describe this, it's technically polarity - when pickups are wired with one reversed, only the differences in the two pickups are heard, since their opposite amplitudes cancel. It's like where the wiki says:
"And if their peak amplitudes are equal, their sum is zero at all values of time, t."
This happens, but the two signals aren't identical due to manufacturing differences, different output levels and different positions along the string, which would probably emphasise certain natural harmonics.

Dirk Gently
12-30-2006, 12:00 PM
I thought TPQ was right - phase shouldn't actually be used to describe this, it's technically polarity - when pickups are wired with one reversed, only the differences in the two pickups are heard, since their opposite amplitudes cancel. It's like where the wiki says:
"And if their peak amplitudes are equal, their sum is zero at all values of time, t."
This happens, but the two signals aren't identical due to manufacturing differences, different output levels and different positions along the string, which would probably emphasise certain natural harmonics.
You're not hearing opposite "amplitude," which describes the distance between 0 and the pinnacle of the crest or trough of the valley of the wave. What it's talking about is when in time the peak amplitude is occurring. The opposite polarity causes exactly that effect. If you want to hear it in a non-guitar environment, go in your car, unhook one of your speakers, and then reverse the positive and negative. I'll even throw in a link to the Wikipedia article that shows a graphical representation of what "phase" is, which reinforces my explanation perfectly. Output level and the rest of that jazz has nothing to do with it.

http://en.wikipedia.org/wiki/Phase_%28waves%29#Phase_shift

Wyld Stallyn
12-30-2006, 03:20 PM
I know what phase and all that is, I don't want to start arguing, all I'm saying is that having reverse wired pickups produces a thin nasally tone because you're hearing the difference of two signals, which are different because of output level and the fact that certain overtones will have nodes beneath the pole pieces.
I also thought that positions 2 and 4 wired the pickups on a strat as humbuckers - mine do anyway.