Define "phase"? Or is it polarity?

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It does mention time...actually the whole definition relies on time as the factor by which something is considered being in or out of phase - which totally sucks because I was so ready to accept the arguments against time having anything to do with it as presented a few posts back with pics and logical explanations and such... What a mess, heh..
Here's the crux of the misunderstanding, Hippo, "Out of phase" and "different phase" do not necessarily mean the same thing. Two waveforms can be of the same intrinsic phase, but with one delayed down the timeline, and they will be out of phase with each other. That picture which you liked so much in Problem 4 is a textbook example. The two waveforms are of the same intrinsic phase; there is absolutely no physical or mathematical difference between the two waves. Yet they are out of phase with each other, simply because they start at different times.

And sonixx, my indefatigable friend, you are just taking the voltages inverting their polarity, and adding offset. This is what I did way back in my first post in this thread when I said V2 = (V1 * -1) + VDC

I said this simply to demonstrate the difference in results between a polarity shift around 0DC and a phase shift around the rest voltage. But it is not really performing a phase shift.

If you wish to actually do it via a true phase rotation - without having to introduce time or a time shift into it whatsoever - one simply needs to add the desired amount of phase rotation in radians to the resulting sine value. The cool thing is anybody reading this can try it for themselves using only the scientific version of the caclulator that comes with their Windows OS. As long as you have a calculator with a sin(x) function button , it's easy to do:

For any current sine wave value x in radians, (see chart)
VLObject-3552-060109110156.jpg
simply calcuate sin(x + 3.1416) + VDC and that will give you the new y value for the inverted wave, without flipping polarity, and without introducing any time shift or time value whatsoever. Try it yourself guys. The proof is right in front of you as are all the tools you need. No need to look anything up when you can perform the experiment yourself.

That's for a sine wave. For a complex wave, it's exactly the same, but first one must use the Fourier transform to separate out the component sine waves first, Then the time-independent phase shift functions can be applied to those before they are re-integrated into the complex wave. This yields the single-value phase rotation on the z circle for a complex wave the same way we saw that it it does for a sine.
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And sonixx, Dirac functions is the formal name of the unit impulse functions. Anybody who knows spit about physics knows who Paul Dirac is.

G.
 
...If two things are happening in/out of phase they are reaching the same or related stages at the same time/at different times...
I give you credit for one thing.. understanding that. ;) Right now I can't even wrap my head around what they're saying.
Maybe after a break.
 
Glen, or anyone, just to ask and clarify something here. I was of the understanding that the differences in the sound at two distances was due to things like differences in frequency response/attenuation rates, radiation patterns, proximity effects, reflections and such. That with the exception those types of effects the two pass through the air for the most part with their frequency/time alignment unchanged (if that's the correct way to say that).
Yeah, you're right on all counts on that one, Wayne. I got caught up in another thought and tripped myself up, and I was wrong with what I said there. Nice catch, and thanks for the correction on that one.

But maybe that will help to reinforce what I just told Hippo. The intrinsic phase of the waveform at the two mics does indeed stay the same, there is only a time delay. Slide them back together in time and they are in phase (minus the other physical effects you mentioned.) This again is just like the waves in Problem 4, the intrinsic phase of the two waves remains the same. It's the time delay that puts them out of phase with each other, even though there has not been an actual phase change affected to the wave.

G.
 
This again is just like the waves in Problem 4, the intrinsic phase of the two waves remains the same. It's the time delay that puts them out of phase with each other, even though there has not been an actual phase change affected to the wave.

G.

What are you referring to by an actual phase change affected to the wave? Or the notion of intrinsic phase.

Phase is a time based relationship between two or more waves.
 
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Phase is a time based relationship between two or more waves.
Phase is a property, not just a relation, and it is a property independent of frequency. Just as frequency can be manipulated separate from phase - we're all used to that idea - phase can be manipulated separate from frequency.

Look at it this way; you could also say that amplitude is a relation, that amplitude can only be measured against some reference amplitde. To say that something has a certain SPL or a certain voltage or a certain VU level requires something to use as a standard base level to compare it against.

It's no different with phase; intrinsic phase value can be calculated against a reference. In this case we're assuming the reference phase is what is yielded by the pure sin(x) function with no phase offset added to the x value; this is what would be called 0° phase rotation. Cosine has a phase rotation of pi/2 radians (90°) from that base reference. A 180° shift is a phase rotation of 3.14 radians. and so on.

Look, guy, throw all the time-based equations back at me that you wish; the fact remains that all one has to do to rotate the phase of a waveform is to add the amount of phase change in radians to the current x value in radians of the current sine. It doesn't matter whether it's radians/sec or radians/year; the frequency is irrelevant and time is not even part of the equation.

I have given you and everybody reading this the simple, time-independent formula for rotating the phase of a sine wave without shifting it in time. Anybody with a Windows calculator, that graph I gave in the last post, and about 20 minutes can overlay a phase-shifted but non-time-shifted version of that sine wave shifted by any number of degrees they wish by simply converting degrees to radians and plugging that value into the equation. They can plot those new values right on that chart, connect the dots, and show the whole world that they performed a phase shift to the original sine with no time shift whatsoever and without having to take my or anybody else's word for it. If anybody can do it, you really should stop saying it can't be done.

G.
 
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I give you credit for one thing.. understanding that. ;) Right now I can't even wrap my head around what they're saying.
Maybe after a break.

That's hilarious, hahahaha.. Because I had just woken up from a nap when I looked it up - I bet I wouldn't have gotten it either without said nap :D
 
Frequency and phase are two separate properties of any waveform
Phase is a property, not just a relation, and it is a property independent of frequency. Just as frequency can be manipulated separate from phase - we're all used to that idea - phase can be manipulated separate from frequency.

Show me. What would a 1KHz sine wave starting at T=0 look like when you change the phase? What are you changing? Not Gain. Not Frequency. Not Time. What?

For this discussion you cannot remove time. Time is the X-Axis and must be in the equations, otherwise one cannot predict the wave value. Time is required to calculate the phase relationship.

Phase is not a property just as time is not a property. Asking the question what is the phase of a wave is nonsensical. Asking the question, what is the phase relationship to another wave is relevant.

Also, the sine function is a unit gain function and only predicts such. The gain in the system predicts the final value, which is not really relevant in the discussion.

Here's the equation that describes and predicts the sine wave unity gain values versus time (as a mic would see it) irrespective of system gains.

f(t) = A *sine (w * t ) for t >= 0

this predicts the unity gain amplitude f(t) at any given time t for frequency w with A = 1. A represents system gain.

I wasn't going bother, but your equation is incorrect for polarity inversion

Your equation: V2 = (V1 * -1) + VDC is incorrect

The correct form is V2 = -1 * (Vdc + V1) = -Vdc - V1

Your equation is inverting V1 and applying a bias after the fact.

Also, your (albeit irrelevant) Spring example of in place phase change has absolutely no bearing to this discussion.

It's obvious to me that you have no formal or very little education in math related disciplines and especially engineering as is witnessed by your inability to correctly craft equations. You may have vast and far reaching knowledge(s) in many areas, but as is said, this ain't one 'em.

On a positive note though, I do appreciate you taking your valuable time to give us insight into your vast knowledge and infinite wisdom... It's very informative.
 
Show me. What would a 1KHz sine wave starting at T=0 look like when you change the phase? What are you changing? Not Gain. Not Frequency. Not Time. What?
You are changing the Y value - the amplitude - for any given position in the wave by a set number of radians. This is exactly what phase change IS; it is a rotation in the phase angle of the waveform.

What would it look like? It would look EXACTLY like the very first graphic that Reel posted to this thread way back on page 1. Both wave start at t=0 and end at exactly the same place in the timeline but the amplitude of the wave at any given position has changed.

Of course, if you bothered to actually do the science and perform the exercise that I offered to everybody, you'd already see that.
For this discussion you cannot remove time.
I can, I have, I did :).
Time is the X-Axis and must be in the equations, otherwise one cannot predict the wave value. Time is required to calculate the phase relationship.
If there is no movement along the x axis, then it need not be an extra variable in any basic calculation of phase, since it's values are not changing. The only necessary reference to time is in the value of x itself, which indicates at which point in the timeline the amplitude calculation is being made.

You're making a circular argument, Sonixx. One one hand you're saying that phase change requires a time shift; and then on the other you're saying that since there is no time shift, there cannot be a phase change. Those are just two ways of saying the same thing, not proofs of each other.
Asking the question what is the phase of a wave is nonsensical. Asking the question, what is the phase relationship to another wave is relevant.
And asking the question, what is the phase relationship to some stating phase is equally relevant. There do not have to be two waves, it can be a comparison of the state of a wave as compared to that same wave's original state before changing the phase angle value. That shows right there that phase is a property of that wave, it is a property that can be measured and changed without having to introduce a second wave.

Phase can also be measured as a property value versus a standard gauge. One uses the simple sin(x) function to indicate a wave with 0° phase rotation. Already we have identified a phase state without introducing time or another wave. Rotate the phase of that sin by pi/2 radians, and we have changed the value of that property in such a way whereas we have given that object a diiferent name; it's called cosine. So now we are giving two different names to the same wave, just by changing the value of one of it's properties: that property would be the phase angle, or, simply, the phase.

Look at the phase of the moon. We don't need two moons to say whether the moon is half full. We don't need two moons to have phase; the phase of one moon is half full, based upon using what we know a full moon to be as a reference. The phase of the moon is a property of the moon and not a relation between two different moons.
Your equation is inverting V1 and applying a bias after the fact.
Yep. Glad to see you understand at least one of the basic things I said.
Also, your (albeit irrelevant) Spring example of in place phase change has absolutely no bearing to this discussion.
Dead wrong on this one, ace. Once you break through your stubbornness and understand that phase can be treated as a property just like frequency and amplitude can be, then introducting phase to the z axis is not only proper and relevant, but it's something that done in math and science all the time. Hell, where would the entire discipline of non-linear dynamics and chaos theory be if we couldn't chart signal values in phase space like that?

You can't tell me, just for a second example, that nowhere during the course of your schooling for your EE that you never saw a dampened oscillation represented in phase space as an inward trending spiral on the z axis with a fixed attractor at y0 , z0. They can do that because they know they can treat phase as a third property of the signal along the z axis, with amplitude on the y axis and time on the x.
It's obvious to me that you have no formal or very little education in math related disciplines.
Did you steal that line from Murray Gell-Mann? :D

You can throw out all the formal math you want, and try to impress those reading this that are not so math inclined, but it's meaningless if it's only providing a circular argument and not an actual mathematical proof (or disproof) of the question at hand.

I'll admit, I'm not as good as you at pulling equations out of old text books or web pages, but I'm a damned sight better at understanding the reality of what all those letters and numbers actually mean and are telling us.

I'm still waiting for your solution based upon the use of convolution impulses, BTW...or is that just another buzzword you picked out of a page somewhere? And I'm still waiting for you to actually perform the extremely simple (for someone so well-versed in formalized mathematics) experiment I offer for rotating phase of a wave in place.

G.
 
I'll admit, I'm not as good as you at pulling equations out of old text books or web pages, but I'm a damned sight better at understanding the reality of what all those letters and numbers actually mean and are telling us.

ha, I guess that's based on you own experience, but not mine. The only reference I had to review was the Unit Impulse.

You can throw out all the formal math you want, and try to impress those reading this that are not so math inclined

I love it... you set up a straw man by asking for equations, you ignore them and ask another often irrelevant question and then accuse of not answering your question... now accusations of braggadocio... classic

You can't tell me, just for a second example, that nowhere during the course of your schooling for your EE that you never saw a dampened oscillation represented in phase space as an inward trending spiral on the z axis with a fixed attractor at y0 , z0.

stability of systems is determined by where the Poles and Zeros are positioned in the S-plane (Laplace Transform) within the unit circle. I don't have a clue about this Z-Plane you are so obsessed with.

You're making a circular argument, Sonixx. One one hand you're saying that phase change requires a time shift; and then on the other you're saying that since there is no time shift, there cannot be a phase change.

a circular argument... hardly.

more like if A=B then B=A

Look at the phase of the moon.

irrelevant.

I can, I have, I did

then there's nothing to discuss. Recording is managing time based signals in the time domain. sin(x) maybe be okay in 10th grade trig, but sin(wt) is required to discuss this at this level... and no you can't divide the t from f(t).

I'm out and it's no capitulation. it's that your understanding is so Sophomoric this is an exercise in futility
 
On the lighter side. Its something my mom told my dad I was going through.
 
There's the old story of the carpenter who only had a hammer. When asked that there was something loose that needed tightening, what did he think it was, he responded by showing everybody his hammer. He passed it around, and described how it worked, how it had a heavy head on it with a flat face that was meant to drive a nail.

He then proclaimed that, since the hammer was meant to drive a nail, the problem must be a nail. If it were anything else, the hammer would not be designed that way.

When someone else said that he actually saw the problem, and that the problem was something called a wood screw that needed tightening down, and that it was tightened down by sliding a blade in a slot in it's head and turning it, the carpenter just scoffed and laughed at such an absurdity. "I've already showed you the hammer, and how it worked, and there's nothing there about a blade or a slot or turning anything. That's not how nails work. Nails are made to be hammered down."

"But how do you know it's a nail?", someone asked. To which the carpenter simply replied, "It has to be, because that's what hammers are designed to drive. I'm a carpenter, and have been for a long time. I know from where I speak."

This went back and forth, around and around in circles, with the carpenter stuck in the loop that because he had a hammer, the problem was always a nail, and as proof he kept saying, if it weren't a nail, then this wouldn't be a hammer. They argued for an hour.

In the meantime, the original guy who actually looked at the problem, and not at what tools anyone did or did not have, actually looked at the situation, saw it was a wood screw, went down to the hardware store and got a new tool called a Phillips screwdriver and got the problem solved himself.

Sonixx is, I'm sorry to say, presenting us with the perfect example of the carpenter and the hammer.

There is nothing wrong with those time-based equations he keeps regurgitating as his argument. they are perfectly valid equations, just as the carpenter's hammer is a perfectly good hammer. And as long as he sticks with those as his only tool, he'll be stuck in his beliefs.

See, the "w" in those formulas stands for radians per second. This means it stands for how fast in time that a wave is rotating through it's cycle. It's really just another version of "cycles per second" with approx. 6.28 radians per one cycle. This means those equations are specifically for calculating and manipulating the frequency of the sine wave, and yes because we are talking about how many things are happening per second, there is a definite time base and time dependency to those equations.

And sonixx keeps coming back with the argument that because time is crucial to those equations, that it must be crucial to phase as well. Because his hammer is flat, the problem must be a nail.

The problem with that is that phase is idependent if frequency. Take a look at any and every one of the charts presented in this entire thread - and there have been a lot of them :). Take a look at the waves in any one of them and tell us what their frequency is. We can't determine their frequency because nowhere is the time base defined. Those sines in the first diagram could have a frequency of 1Hz, 100Hz, once a day, or once a month (like the completely relevant phases of the moon.) The frequency is not defined in any of those charts exactly because it's frequency is not important. In fact, look at that last one; the x axis is measured in radians (position on a circle), not in any unit of time. Phase can be talked about, diagrammed and manipulated without any need to define the time.

As I argued from the very start, shifting in time can indeed bring things in phase or out of phase, and can cause things to resemble a phase change. Move a 1Hz sine wave one second down the timeline and it will resemble a phase inverted version of another sine of the same frequency that has not moved. I never said that was not true, and that is what his equations support. That is phase relation, just as sonixx said. But it's NOT a phase change.

The problem is, the only thing that has changed in the moved wave there is it's position on the timeline. Other than it being delayed, nothing has changed about it's description. It's frequency, amplitude, in fact it's complete physical and mathematical description has not changed one bit. It's frequency, it's amplitude, and yes, it's phase, have not changed. It just starts one second later, that's all.

But that can't be possible, comes the reply. The equations show time, therefore time has to be there. There is no such thing as intrinsic phase. And since time has to be there, phase has to take place as a relation in time.

It's a circular argument. That has to be a nail, because this is a hammer; therefore, since that is a nail, this hammer is the right tool.

The Phillips screwdriver in this case is the concept of phase space and the diagramming of phase as a third property in the third dimension, and just how simple it can be to rotate - change - the phase of a single waveform without having to slide it down a timeline and compare it to another wave. This is a valid concept and mathematical tool that is used every day in physics, chemestry, medicine and, yes, even electronics engineering. The fact that sonixx is unfamiliar with it is something I cannot account for other than maybe they just did not cover it in his classes. I mean, this thread contains someone else who graduated from audio engineering school and he doesn't know and doesn't care what polarity is. :rolleyes:

But even then, the idea of phase as a property even simpler to see, and doen't need the z axis. That "experiment" I gave you guys, which I'm sorry that nobody has taken me up on yet is almost painfully simple in it's execution. All you have to to is take a sine wave, use that graph I gave you, and for every point on that x line in radians, add some number of radians to each value to represent a rotation in the phase value, and then take the sin of each sum. Plot each result in the graph. What you'll wind up with is a phase shifted representation of the original wave, without any movement in time whatsoever, and without any fancier frequency-based equations.

Don't take my word for it. Try it for yourself. :D

G.
 
Here's the crux of the misunderstanding, Hippo, "Out of phase" and "different phase" do not necessarily mean the same thing. Two waveforms can be of the same intrinsic phase, but with one delayed down the timeline, and they will be out of phase with each other. That picture which you liked so much in Problem 4 is a textbook example. The two waveforms are of the same intrinsic phase; there is absolutely no physical or mathematical difference between the two waves. Yet they are out of phase with each other, simply because they start at different times.

And sonixx, my indefatigable friend, you are just taking the voltages inverting their polarity, and adding offset. This is what I did way back in my first post in this thread when I said V2 = (V1 * -1) + VDC

I said this simply to demonstrate the difference in results between a polarity shift around 0DC and a phase shift around the rest voltage. But it is not really performing a phase shift.

If you wish to actually do it via a true phase rotation - without having to introduce time or a time shift into it whatsoever - one simply needs to add the desired amount of phase rotation in radians to the resulting sine value. The cool thing is anybody reading this can try it for themselves using only the scientific version of the caclulator that comes with their Windows OS. As long as you have a calculator with a sin(x) function button , it's easy to do:

For any current sine wave value x in radians, (see chart)
VLObject-3552-060109110156.jpg
simply calcuate sin(x + 3.1416) + VDC and that will give you the new y value for the inverted wave, without flipping polarity, and without introducing any time shift or time value whatsoever. Try it yourself guys. The proof is right in front of you as are all the tools you need. No need to look anything up when you can perform the experiment yourself.

That's for a sine wave. For a complex wave, it's exactly the same, but first one must use the Fourier transform to separate out the component sine waves first, Then the time-independent phase shift functions can be applied to those before they are re-integrated into the complex wave. This yields the single-value phase rotation on the z circle for a complex wave the same way we saw that it it does for a sine.
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And sonixx, Dirac functions is the formal name of the unit impulse functions. Anybody who knows spit about physics knows who Paul Dirac is.

G.

Two waveforms can be in phase or out of phase but have a certain offset. The offset is the DC component. There are also two kinds of offset. There is an X and Y offset depending. Each signal cannot be taken alone. Phase and offset only apply to two signals in relation to each other.
 
Aaaargh, doupbe post...sorry. :(

G.
 
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Two waveforms can be in phase or out of phase but have a certain offset. The offset is the DC component. There are also two kinds of offset. There is an X and Y offset depending. Each signal cannot be taken alone. Phase and offset only apply to two signals in relation to each other.
Not quite true. Offset can be applied to a measure standard. For example, one does not need to have a second wave to say that a lone wave has a DC offset (y axis) of 3VDC, because we have already defined 0VDC as the reference for zero offset.

When we measure the temperature of something, it's really just a relation to a calibrated standard. 90°C simply means it's 90° warmer than the temperature at which water freezes.* It's really just a relation. +3dBVU is just a relation stating that we have a voltage level 3dB above a calibrated standard of "line level" (approx, 1.23V for pro line level). Yet we can and commonly do treat those values as intrinsic values all the time.

A similar approach can be applied to phase as well. If, for calibration purposes, we predefine a certain condition as having 0° phase offset - for a sine wave that would commonly be the pure sine function of y=sin(x) - then if we apply an offset to the phase angle from that (y=sin(x + Θ), where Θ equals the amount of phase angle offset), we can identify that as a different phase state without requiring a second waveform to compare it against.

To use common language, *everything* is measured as a relation. It's just a question as to whether it's measured as a relation to another sample measurement (which is what you're referring to), or whether it's measured as a relation to a pre-defined calibration or standard.

This is as true of phase as it is of any other measurement. While we're "used to" thinking of temperature as an intrinsic value (i.e. a property), it is equally a relation between the current measurement and a hypothetical measurement taken in a cup of ice. Conversely, we're "used to" thinking of phase as a relation between two measurements - and it can indeed be, that is valid - it is equally an intrinsic value (i.e. a property) based upon a relation to a calibration standard.

G.

*with one degree Centigrade being definable as 1/100th the distance from the temperature at which water freezes and the temperature at which water boils.
 
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To use common language, *everything* is measured as a relation. It's just a question as to whether it's measured as a relation to another sample measurement (which is what you're referring to), or whether it's measured as a relation to a pre-defined calibration or standard.

]
Sorry for beating a dead horse but isn't the " pre-defined calibration or standard " just "another sample measurement". In your own examples you are comparing "90°C simply meaning it's 90° warmer than the temperature at which water freezes" but doesn't water freezing represent degrees too? Doesn't line level represent a voltage too?

If you turn a screw into a piece of wood, as you turn it, it moves either in or out unless it is stationary and then it's the wood that moves. When you turn a wave(change it's phase angle) does it not move either up or down the time line or if you hold the wave stationary(if possible) wouldn't the time line effectively move? Maybe with enough gigawatts(1.21) and a flux capacitor we could make a time machine?:confused::eek: :o
 
Not quite true. Offset can be applied to a measure standard. For example, one does not need to have a second wave to say that a lone wave has a DC offset (y axis) of 3VDC, because we have already defined 0VDC as the reference for zero offset.

When we measure the temperature of something, it's really just a relation to a calibrated standard. 90°C simply means it's 90° warmer than the temperature at which water freezes.* It's really just a relation. +3dBVU is just a relation stating that we have a voltage level 3dB above a calibrated standard of "line level" (approx, 1.23V for pro line level). Yet we can and commonly do treat those values as intrinsic values all the time.

A similar approach can be applied to phase as well. If, for calibration purposes, we predefine a certain condition as having 0° phase offset - for a sine wave that would commonly be the pure sine function of y=sin(x) - then if we apply an offset to the phase angle from that (y=sin(x + Θ), where Θ equals the amount of phase angle offset), we can identify that as a different phase state without requiring a second waveform to compare it against.

To use common language, *everything* is measured as a relation. It's just a question as to whether it's measured as a relation to another sample measurement (which is what you're referring to), or whether it's measured as a relation to a pre-defined calibration or standard.

This is as true of phase as it is of any other measurement. While we're "used to" thinking of temperature as an intrinsic value (i.e. a property), it is equally a relation between the current measurement and a hypothetical measurement taken in a cup of ice. Conversely, we're "used to" thinking of phase as a relation between two measurements - and it can indeed be, that is valid - it is equally an intrinsic value (i.e. a property) based upon a relation to a calibration standard.

G.

*with one degree Centigrade being definable as 1/100th the distance from the temperature at which water freezes and the temperature at which water boils.

In motion control. it is the way it is. In sound, there are the mathmatics of the waveforms and the effect of the airwaves. The math holds true except when the sound enters any room. Phase coming from speakers has way too many components to pin down in a simple argument such as this. Our brain automatically rejects and adjusts to any sound and. in fact, we determine the direction of sound with phasing. There are simply too many factors that are in play when the electrical signals enter the atmosphere.

Sonixx is just thinking "in-the-box" and you are thinking "out-of-the-box"
 
Sorry for beating a dead horse but isn't the " pre-defined calibration or standard " just "another sample measurement". In your own examples you are comparing "90°C simply meaning it's 90° warmer than the temperature at which water freezes" but doesn't water freezing represent degrees too? Doesn't line level represent a voltage too?
Yep, that's why I said that everything we measure is measuring a relation. Even when there is something that nobody argues whether it's an intrinsic property or not - like temperature or amplitude, both of which we all pretty much agree (I hope! :) are normally considered properties of objects - the only way one *can* measure it or assign it a value is by relating it's condition to something else. When I say I'm 5'10" tall, that is just a relation to the agreed upon standards for the length of a foot and an inch.

What it comes down to, Star, is that any aspect of an object that is measurable is a property of of that object, and that any measurement is a relation of that property's value to "something else". Whether that something else is another object or a standard of measurement (which really is in itself another object) is not that relevant to the actual definition of the property.
If you turn a screw into a piece of wood, as you turn it, it moves either in or out unless it is stationary and then it's the wood that moves. When you turn a wave(change it's phase angle) does it not move either up or down the time line or if you hold the wave stationary(if possible) wouldn't the time line effectively move?
That's taking the analogy a bit too physically and literally. Remember that I cautioned way back in this thread not to take the Z axis as a literal third dimension. Because, in fact, the x and y axies are not literal physical dimensions either. We do not have three-dimensional spirals shooting through the air at our ears any more than we have two-dimensional sine waves shooting through the air at our ears. Nor are either the sine or the spiral actual physical objects.

We are simply looking at mathematical graphs, and the "dimensions" involved are completely mutable by math, and only affect each other in what ever way the math tells us it does. For an oversimple example, if the x axis represents time, there's nothing to stop us from jumping back and forth in time at will simply by moving our pencil back and forth on the timeline. No black hole generators required :D.

Remember the equation: y = sin(x + Θ). The layout of that equation is the answer to your question. We are not changing the value of x - meaning we are not moving on the timeline - rather we are changing the value being input into the sin function itself. What change does that cause? It causes a change in the value of y, the amplitude. That's what the equation *is*, it is an equation for calcualting the value of y for any given position x. The "+ Θ" part of it is simply indicating the change in phase angle being applied.
MCI2424 said:
In motion control. it is the way it is. In sound, there are the mathmatics of the waveforms and the effect of the airwaves. The math holds true except when the sound enters any room. Phase coming from speakers has way too many components to pin down in a simple argument such as this. Our brain automatically rejects and adjusts to any sound and. in fact, we determine the direction of sound with phasing. There are simply too many factors that are in play when the electrical signals enter the atmosphere.

Sonixx is just thinking "in-the-box" and you are thinking "out-of-the-box"
Well, first, let's go back to the title question of this thread. "Define phase" (especially in relation to polarity), and the original post that got us started down this path that stated that a change in phase required a shift on the timeline. All I have been doing is trying to give a much more fundamental description of what phase *actually is* and that any definition that says that phase requires such a shift is actually quite incorrect. The only thing "out of the box" about it is that it is a correct definition that most people get wrong. The "in the box" conventional wisdom is an incomplete definition that leads to incorrect conclusions and proclamations, such as "time shift is required for phase shift". I've been at this stuff for three decades but it wasn't until the early 90s that I actually started wrapping my head around the whole picture. Before that I was right with you guys. It ain't easy to change mindsets, that's for sure.

It's funny that you refer to "in the box" thinking, MCI :). Because it's ITB (in our audio gear definition of ITB) where this is most evident. While it may be true that once the sound waves leaves the loudspeaker, there's not much we can physically do to the phase other than cause delays to throw things in and out of phase with each other, that doesn't change what we can and cannot do to the electrical voltages while they are still in the box, and in that domain everything I have said holds true and relevant. Looked at that way, I'm the one thinking "in the box" :D. And lets not forget that this thread was about phase vs. polarity (another electrical property) and about any plugs (ITB software) for manipulating it.

But it still remains that the concepts covered here do not apply only to electricity, it's not a matter of "ITB" vs. "OTB". Its that the box is actually larger than many folks realize. It's more like mechanistic vs. relativistic. Not literally, but in similar change of viewpoint and scope. It's kind of analogous to Sonixx using a set of perfectly good Newtonian-view equations, and my responding with E=mc2. They both are "correct" as far as they go, but the relativistic view goes much further in it's understanding and description of the underlying reality, opens up new perspectives of that reality just not visible from the mechanistic view, and shows that some of the further conclusions made by the mechanistic view alone are incorrect.

G.
 
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Define phase:

1: a particular appearance or state in a regularly recurring cycle of changes <phases of the moon>
2 a: a distinguishable part in a course, development, or cycle <the early phases of her career> b: an aspect or part (as of a problem) under consideration
3: the point or stage in a period of uniform circular motion, harmonic motion, or the periodic changes of any magnitude varying according to a simple harmonic law to which the rotation, oscillation, or variation has advanced from its standard position or assumed instant of starting
4: a homogeneous, physically distinct, and mechanically separable portion of matter present in a nonhomogeneous physicochemical system
5: an individual or subgroup distinguishably different in appearance or behavior from the norm of the group to which it belongs ; also : the distinguishing peculiarity
— pha·sic Listen to the pronunciation of phasic \ˈfā-zik\ adjective
— in phase
: in a synchronized or correlated manner
— out of phase
: in an unsynchronized manner : not in correlation
http://www.merriam-webster.com/dictionary/phase

That is from a source that is not openly editable by any old dude who can just put whatever crap they want on there (which was the argument that disqualified wikipedia, I believe)... and it seems that number 3 is the relevant definition to this discussion, right?

What is interesting is the use of the word "simple". How can the makers of the dictionary have the definition of the word so wildly incorrect? And if they are not incorrect - what is the simple harmonic law they are talking about? I mean... not to be offensive to either of the posters - but you guys are being so complicated, when the poster asked for a definition, and the very definition of the word as it applies here states that it involves a simple harmonic law. It is quite bewildering to those of us with no engineering degrees (or whatever) how the discussion of the definition has gotten this complicated.

Is it really not simple? Is the merriam-webster dictionary not a good source for the definitions of words?
In refreshing the screen, I re-read this very good and important post that Typhoid Hippo made at the top of this page. In the heat of the debate, I unfairly missed this post earlier.

Please note, Hippo, first that there are many definitions that apply to phase, there is not one single definition. Then note that the first three definitions given apply directly to and agree with what I have been saying all along. The harmonic law is basically the idea of sines and sine waves.

Note that definition 3 applies to both my and Sonixx's position when it states, "the rotation, oscillation, or variation has advanced from its standard position or assumed instant of starting." An advance in rotation is what I'm referring to, and an advance from assumed instant of starting is what Sonixx is referring to.

Plus, definition 5 can be read as applying to what Sonixx and others are saying, where phase can be considered as relative to the "norm", or in this case, the original un-shifted wave. This is where the concepts of "in phase" and "out of phase" spring from.

Those definitions covers us both, which is where part of the confusion comes in. The difference is that I have agreed all along with Sonixx's part as far as it goes, I was just trying to go the rest of the way to include the rest of the definition(s), whereas Sonixx was arguing only the smaller picture, only the part related to time shift, and denying the rest as irrelevant.

It really is NOT that complicated once one gets the whole picture. What makes it hard is that virtually all of us - including myself - were "brought up" being taught an incomplete or obsolete view of the big picture. Even in college. Sonixx has an EE degree and he still was shown only part of the picture. I have two computer and electronics degrees and it wasn't until some 12 years or so after I got my diplomas where - through extra reading and study with newer and more expansive textbooks than I had in class - I was slowly exposed to and began to understand the larger picture.

It's very hard to "convert" oneself, and as this thread shows, even harder to "convert" others to the bigger picture/larger box when the smaller, incomplete picture has been taught to us by and ingrained in our thinking for so long. That's the hard part, getting from there to here. Once here, it's much easier than one would think. :)

G.
 
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we're "used to" thinking of phase as a relation between two measurements - and it can indeed be, that is valid - it is equally an intrinsic value (i.e. a property) based upon a relation to a calibration standard.

In wave theory "phase" is always a relative concept: it is defined as such. Whether this relative nature reveals itself in time or space -- we are talking classical physics I presume ;) --, it is not an intrinsic property of any wave: waves do not have "a phase" the same way they have an amplitude. Whenever people speak of "the" phase of a certain wave, they are simply implicitly assuming a common point of reference in spacetime that is relevant to that particular observation.

Think about it this way: even if I don't know the particulars of your oscillator, I can still determine the amplitude and frequency of the waves that it produces. But I cannot measure "the" phase.

So I think it is the other way around: people have come to think of "phase" as an intrinsic property of waves. But it is not.
 
In wave theory "phase" is always a relative concept: it is defined as such. Whether this relative nature reveals itself in time or space -- we are talking classical physics I presume ;) --, it is not an intrinsic property of any wave: waves do not have "a phase" the same way they have an amplitude. Whenever people speak of "the" phase of a certain wave, they are simply implicitly assuming a common point of reference in spacetime that is relevant to that particular observation.
The problem is those two sentences contradict each other. If the second sentence is satisfied, then there is no problem with the first. If there is a common point of reference or a calibration standard, then phase can be talked about as having an intrinsic value in relation to that standard.

To put it incredibly simply: If it can be measured, it is a property.

Which brings us to the nest quote:
Think about it this way: even if I don't know the particulars of your oscillator, I can still determine the amplitude and frequency of the waves that it produces. But I cannot measure "the" phase.
You can if you can measure from the start of the wave; i.e. if you know when the wave began. If you just take a sample of a wave, then no, you can't. By looking individually at a sine and a cosine, for example, there is no way to tell which is which if looking at just part of the continual function. One could be just a time shifted version of the other, and indeed, in that case the only way we can talk about phase is as a relation between the two and not as an intrinsic value. That is absolutely correct.

But when we move to the real, physical world with something like an audio timeline, if we can view the entire waveform - or at least the beginning of it - then the ambiguity collapses and we can see whether the phase difference is a relative or intrinsic one. Again, take it back to problem #4. We can both visually and mathematically determine that the two waveforms are identical because we can see them from their starting points and we can measure whether there is offset between the two in their x-y relationship. The two waves are identical in nature in that regard, and can be recreated using the same equations with the same plugged-in values, so it is fair to say that they have the same "intrinsic phase".

If however, it turns out that an offset needs to be added to the value fed to the sin function in order to recreate the wave correctly, and this offset is different that what the original wave needed, then it is fair to say that it has a different "intrinsic" phase angle or phase value.

[WARNING: Early Morning Rant That I'll Probably Regret One Second After Posting]

I don't know how many more and different ways I can explain the same thing over and over again, guys. I'm out. I wish someone out there would actually *think* for themselves about what is going on (on all sides) and *apply* the information they have instead of just recite it. Work from first principles and take it forward. Run the thought or physical experiments, think about what the results actually say, reason it out to the end, etc. Morningstar seems to be just about the only one who is actually thinking about it. Yeah Star got an Excedrin headache thinking about it; you know what, so have I a few times during this thread. Sometimes when you exercise your muscles get sore. No pain, no gain.

I'm out of strained peas for this thread. I have no more ways I can think of to explain the same simple little concept over and over again, only to have someone recite the same pablum over and over again without actually thinking about how the two relate and coexist. We just keep talking past each other.

Believe what works for you, folks. None of this has anything to do with creating good music anyway.

G.
 
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