Speaker Phase

[C Moore]

Do you guys honestly hear a difference.?
If you did not know.....AKA a blind test......could you call out the phase change.? If you think the amp definitely sounds best with the phase a certain way.....could you identify it.....in a blind test,,,,,and say yeah... the phase is this way or that way.?
I cannot even understand what Steve is saying in the quote below.....but he is a much more advanced/experienced player than myself
But honestly.....I have never heard a guy describe phase relationship like this before. Does not mean it is not true.....but why is it not a much more common topic in discussions.?
With all the problems/mods discussed.....just on TAG here....how often does one guy ask another.....did you flip the speaker phase.?
What do you guys think.?

Today, 08:41 PM
kimock
Senior Member Join Date: Mar 2005
Location: Lehigh Valley, PA
Posts: 4,011

Quote:
Originally Posted by zzmoore
But otherwise.....the cones move in and then they move out.

Yeah, don't worry about that part. They do that. .


Quote:
What happens to create a difference, in sound, when phase is reversed.?

The amp and guitar are either working together, increasing the guitar's vibration, or the amp is damping the guitar's vibrations.
The feeling state associated with the amp working against the guitar is:

"This isn't doing anything for me."
Which it isn't. That's exactly what that is: you hit it, it sucks.

The feeling state associated with the positive loop behavior where the amp is pushing the guitar up is "reward".
Which is exactly what that is, because you're literally getting something for nothing. Positive feedback. The sound of the guitar sound makes the guitar sound sound better. Over and over. That would be "preferred".


Quote:
Is there a perception that it is "Bad" or "Good" to have a speaker move "Back" when a battery is parallel connected, with like polarity observed.?
Thank You

No, it's got nothing to do with the battery.

[rdjones]

JBL speakers (the old ones, D, K, and E series) were always reverse polarity compared to everything else.
Positive battery terminal connected to the red connector moved the speaker backwards.
I'm sure there is a majority of people who didn't know this and connected JBLs up "backwards" and never knew the difference.

reddog

[C Moore]

JBL speakers (the old ones, D, K, and E series) were always reverse polarity compared to everything else.
Positive battery terminal connected to the red connector moved the speaker backwards.
I'm sure there is a majority of people who didn't know this and connected JBLs up "backwards" and never knew the difference.

reddog

.....and that is what I mean. Even a guy that says he hears/feels a difference.....would he still hear it, if he could not see which wire went to where. How does it matter....or why does it matter.?
It may be an issue that is far above my level of knowledge.....fine....I do not have a problem accepting that. But from guys that DO HAVE the knowledge......I really do not see it discussed much.
As long as all your speakers, in one cab, are in phase, what does it matter what the relative phase is. The cone goes in and out.
What about 120VAC phase from the wall.? What happens if a plug is wired Hot to the Neutral lug.? Is that going to change things.?
I did not realize a person could hear the difference in phase. Not the first or last time I will say that.......regarding this and several topics.
Thank You

[katopan]

I don't think there's any difference either, as long as, as you say, the speakers in one box are all in phase. And as for the sound either reinforcing or fighting against the guitar strings, well that depends on the distance between the speaker and the strings as well as the wavelength of the notes you are playing. Not to mention the effect of reflected waves and other things. A speaker wired up either way will reinforce the string vibration if you have the volume up and get the distance right.

[Lynxtrap]

I would really like to hear the man explaining that technically. Anybody can say "The amp and guitar are either working together, increasing the guitar's vibration, or the amp is damping the guitar's vibrations"

[rdjones]

The end result is more about total system polarity (phase, if you must).

Polarity inversion can occur at any point in the signal path:
1) How the pickups are magnetized, wound and wired
2) Any effect(s) or signal processing device(s) inline
3) The amp, dependent on number of inverting stages and how the PI and output are wired.
4) Speaker, determined by the magnet's polarity, how the coil is wound and (in the case of the JBLs) how the terminals are identified

Ideally you'd expect absolute polarity to be maintained through the system but really there's a 50/50 chance that the signal can get flipped at various points in the path.

Finally, as Katopan points out, there's the issue of air.
Things get jumbled up quickly after the electrical energy is converted to wiggling air molecules.
Even if everything is perfectly "in phase" it's going to best reinforce the guitar's vibration when you are right up against the speaker.
As you back away those vibration reinforcements will ebb and null with distance and frequency.

rd

[rdjones]

What about 120VAC phase from the wall.? What happens if a plug is wired Hot to the Neutral lug.? Is that going to change things.?

No, not in the real world of guitar amps.
It might change the voodoo aura of a serpent lubricant audiophool system ...

It CAN create a safety and/or noise issue depending on grounding.

I did not realize a person could hear the difference in phase. Not the first or last time I will say that.......regarding this and several topics.
Thank You

Playback polarity does make an audible difference in a studio monitor system, and is most noticeable on drums.

rd

[martin manning]

The main difference for speaker phase has to be the effect on feedback. If you tend to stand in about the same relationship to your amp when you play in both distance and direction, then you will get a similar amount of feedback from the speaker to the guitar (give or take the size and shape of the room and the reflectivity of the walls...). Reverse the speaker wires and you will be likely to get more negative vs. positive feedback or vice versa.

As far as distance goes, moving one-half wavelength would reverse the phase of the feedback, IF all of the sound energy were radiating only along the direction that you moved. The low E on a bass is 44Hz, so a half-wavelength is about 14 feet. For higher frequencies it's less- concert A (high E, 5th fret on a guitar) is 440Hz, so a half-wavelength would be only about 15 inches. In reality there are nodes and antinodes formed in three dimensional space all around the room, so it's much more complicated.

The topic of absolute phase has come up from time to time (the phase of speaker output relative to the phase of the input signal). Given all of the variables, I don't know how one could claim that one way is always better than the other.

[Structo]

We have discussed this before.
Dogears (Scott Lerner) is a proponent of having the amp push the cone on attack.
So am I.
It just feels and sounds better to me. (the hearing part may be arguable)

I messed around with this on my D'lite and I changed that amp so that the speaker cone pushed on attack.
And just the other day I was messing around with my newer 100w ODS and I noticed that it pulled the cone in on attack so I want to reverse that as well.

I can see this by turning the amp up quite loud then muting the strings and strike them as you would a power chord.
On my cab the grill cloth is loose enough for me to see it suck in when I do this.
If your grill is easily removable then all the better to see the cone(s).

There was a recent thread at The Gear Page as well about this.

http://www.thegearpage.net/board/showth ... p?t=380181

http://www.thegearpage.net/board/showth ... p?t=985138

Sorry, I see you quoted that one part, but here is the whole thread.

[Lynxtrap]

The main difference for speaker phase has to be the effect on feedback. If you tend to stand in about the same relationship to your amp when you play in both distance and direction, then you will get a similar amount of feedback from the speaker to the guitar (give or take the size and shape of the room and the reflectivity of the walls...). Reverse the speaker wires and you will be likely to get more negative vs. positive feedback or vice versa.

This is something I could buy, at least in theory.
But if you were to put an amp in the studio while playing the guitar in the control room, and be able to tell the difference between the phase of ONE speaker..? The phase is always in relationship to something else, one signal to the other, from the same source.
If the speaker starts it movement by pulling when you play an A, then it's pushing 1/440'th of a second later. And someone's supposed to hear a difference?
With two speakers, it's a whole different story of course. But one mono source to one speaker? That's Mythbusters-stuff right there.
But if switching + and - in someone's one speaker amp makes that person happier, then it's fine with me.

[diagrammatiks]

there's no difference unless you have 2 cabs out of phase or speakers in the same cab that are out of phase.

in an ideal speaker the response curve of "pushing out" should be the same as "pulling in"

now whether or not a speaker actually behaves like this depends on the speaker. that being said it wouldn't make a difference whether or not the speaker pushed or pulled on the attack.

[martin manning]

The main difference for speaker phase has to be the effect on feedback. If you tend to stand in about the same relationship to your amp when you play in both distance and direction, then you will get a similar amount of feedback from the speaker to the guitar (give or take the size and shape of the room and the reflectivity of the walls...). Reverse the speaker wires and you will be likely to get more negative vs. positive feedback or vice versa.

This is something I could buy, at least in theory.
But if you were to put an amp in the studio while playing the guitar in the control room, and be able to tell the difference between the phase of ONE speaker..?

It's the acoustic feedback from the speaker back to the guitar that's being discussed. If you put the guitar and the speaker in different rooms, you break that loop. (edit: I understand what you are saying, now... see below)

Tom, I can accept that the initial attack being a positive vs a negative pressure pulse might be audible. If that positive pulse comes out from the front vs from the back, or through a port, it's strength would be different.

The initial release of the strings would produce the largest voltage. Whether that results in a push or a pull at the speaker would depend upon whether it came from a down-stroke or an up-stroke, and the magnetic polarity, winding direction, and wiring of the guitar pickups. I believe the later is probably pretty consistent, at least for similar guitar types, Strat vs LP, e.g..

[xtian]

I have to admit to an intense emotional engagement in this argument, even though I've never experimented with it! It's just a thought experiment, but I feel in my gut the speaker-phase-makes-a-difference people are nuts.

First, there's the feedback issue. The sound from the speaker excites the air, which bounces around the room making complex waves everywhere, and interacts with the BODY of the guitar far more than the string itself, and this sets up a mechanical, sympathetic vibration that blooms into feedback when ALL the variables are right. The effect is much more pronounced in hollow bodied guitars. There cannot be a DIRECT relationship between the motion of the speaker cone and the motion of the string, unless you remove all the other variables.

Because of the length of soundwaves, the nodes and antinodes are going to be in the same physical places in your environment when you switch polarity. So if you find a sweet spot where guitar feedback is easy, it's going to be in the same place when you switch polarity.

Finally, the string attack Martin mentions isn't a single sweep of a speaker cone in or out (which is impossible, because what goes in must come out), it's a whole set of waves. Anyone zoomed in on the waveforms in their DAW? Now, this polarity is critical when aligning your kick drum attack among multiple mics, but flip the polarity of all tracks and it sounds the same.

OK, flame away.

[Reeltarded]

Phase for me is paramount. I play multiple amps. I deal with this all the time between AC30 and Marshalls. Easy fix.

[vibratoking]

As Tom said, this has been discussed here quite a few times in the past. Dogears has stated, paraphrasing here, that he can, without any doubt, hear the difference in phase in a double blind test. I absolutely believe him. The problem is, I haven't been able to hear it. I have two speaker cables wired in different phase. I tested them and did not detect a difference. I have not conducted exhaustive tests at many different volumes and situations, but my 'quick' test resulted in no difference to my ears. That being said, I am fairly certain that there is something to it that I am missing or unable to hear. There are certainly people that have more sensitive hearing than others and that are better listeners.

I am an electrical engineer and my logical mind subscribes to many of the previous arguments regarding phase inversions, wavelengths across the frequency spectrum, etc...

At this point, I am willing to say that I may not be sufficiently able to describe the full situation from an engineering point of view and that there is something to this phase thing. I am guessing that if I was in the same room with Dogears doing a double blind test, he would probably be able to point out to me what it is that he is hearing and that I might have an aha moment. I am keeping my mind open on this and plan on taking a closer look at some point.