speaker phase

[woodyc]

I'd be interested to hear from anyone who has found that reversing speaker phase matters in a single-speaker amp.

It isn't necessary to read this part... but if you're wondering why I'm asking its because I just started reading Gerald Webers Desktop Reference book and its an idea that he pushes. In particular, he claims that amps in which the speaker moves forward with a positive signal have a better apparent low end. I'm not sure who originated this idea but it may have been Ken Fisher because it was mentioned in a Vintage Guitar column he wrote about JTM45s and that was a couple years before Weber's book. But Weber has a more elaborate description of the whole thing. He says on p.53-54 that what matters is the phase of the speaker relative to the input signal to the amp. I've run into several people who read about this ask to have the phase of their speakers checked or reversed and I've always politely declined.

[tbryanh]

I've read that too in the places you mentioned.

It doesn't seem that it should matter.

Ken Fisher also said that because an aluminum chassis is a better conductor than a steel chassis, aluminum chassis are faster that steel chassis and that you can hear the difference in pick attack or something to that effect.
I really wonder about this one too.

Ken Fisher and Gerald Weber were both great amp builders and techs, but I think this stuff here is probably snake oil.

[dai h.]

some interesting threads on the gear page if you search their archives like this one:

http://www.thegearpage.net/board/archive/index.php/t-189948.html

[tbryanh]

some interesting threads on the gear page if you search their archives like this one:

http://www.thegearpage.net/board/archive/index.php/t-189948.html
Thats a long thread.

I scanned through it, and there is something that might be true.

Since one half cycle in a distorted amp is different than the other half cycle, it might be that in an open back cabinet, the sound coming out of the front of the cabinet might sound better for one of the half cycles, and the reflected signal coming out of the back of the cabinet might sound better for the other half cycle.

[tbryanh]

It probably wouldn't hurt to have a speaker phase switch.

If nothing else, it could be used to match the phase of a second amp in a bi-amp situation.

[Alex R]

I can see how it might affect acoustic feedback.

[hasserl]

I've been involved in several of these threads at The Gear Page. I've always been very skeptical about it, and have argued my POV quite a bit. But ultimatley the guys there that believe this have provided a decent enough argument that I may not buy it all, but I'll let it go.

The issue is NOT whether a positive signal causes the speaker to move forward or not. The theory that works, for me, is: a distorted output signal is rarely symmetrical, it is often very asymmetrical. And, a speaker's efficiency is rarely symmetrical, most often a speaker will be more efficient when moving in one direction vs the other. So, if you can match the speaker to the amp so that the asymmetry of the output signal matches up with the asymmetry of the speaker efficiency, you may have a result where the amp responds better when driven into distortion, with increased sustain that rolls into feedback better. That's the theory in a very abbreviated account.

I've not experienced it myself, but lots of guys have and they swear they can hear a difference. I'd love to have one of them pick it out in a blind test, but none of them seem willing to put themselves up for such a test.

I'm still not convinced you can even control the positive / negative signal swings. It seems to me that, besides the signal being inverted at every gain stage, so different amp channels will have a different number of gain stages, and will invert the signal a different number of times. But every time you engage or disengage a pedal you'll change the phase of the signal. And I'm not convinced that even the way we pick the strings won't change the phase of the signal. As in, if you pluck the string with an up motion the beginning of the note will be opposite what it will be with a down stroke, right? With all of these variables, how in the world can you control how the speaker moves in relation to plucking or strumming the guitar? I remain skeptical. Until one of these guys that swear it makes a difference shows they can identify this difference in a blind test.

[Sweetfinger]

Ken Fisher and Gerald Weber were both great amp builders and techs...

Um, IMO, one of those is much better than the other :D or should I say, ..was better.. :(

[dai h.]

yup GW doesn't really have much of a technical background. More of a hobbyist portrayed as "guru". Not that everything is wrong but, be careful with his info (co-planar traces, putting alu electros under a lightbulb to reform them, etc.).

[Joe Bee]

Even if the distorted signal were symmetrical I see a mechanism how the speaker phase could affect the sound: Feedback.
Even if the deliberate, squealing type of feedback does only come up in certain genres, there surely is _some_ effect even if the loop gain is less than unity. So switching between negative and positive "acoustical feedback" really ought to have a difference on the sound.

[woodyc]

daih, thanks for the link. I finally read the whole thread at gearpage.

About feedback... with a guitar I don't think the phase of the acoustical feedback has to match the phase of the original vibration since the string is a resonator. It will always resonate when it receives energy at the right freq and the phase can adjust itself to the driving force.

About the Weber/Fisher low end claim... I ordered some parts yesterday to make a footswitch and check it out. The business about phase making a difference when there is asymmetrical distortion seems totally valid, but its not clear to me that it would be audible in any normal situation.

[David Schwab]

I can see how it might affect acoustic feedback.

They put phase switches on electric/acoustic guitars to help control feedback, so it does have an effect.

I suppose if the sound from the amp is in phase to the guitar, you will have enhanced the feedback.

In the case of the acoustic guitars, they put the guitar out of phase from the amp to eliminate feedback.

[Alex R]

Yeah I can see that the string resonates all ways but the body of the guitar will response in phase to a degree I guess. Hence particularly important for acoustic guitar, but I believe a solid body would act that way to a degree also. In fact I should think it does more picking-up of sound that does the string, until it sets off the string to resonating.

[MWJB]

Weber/Fischer's claim is not snake oil, phase is obviously most important when dealing with multi speaker arrays, but is perfectly detectable in single speaker amps. It slightly changes the harmonic character...some speakers really don't like it, most are happy enough either way.

Does it matter? So long as the amp functions as it should it's not going to change your life.

In fact, in less time than it takes to read/write this thread you could have switched speaker leads and tried it. If you don't hear a difference don't worry about it any more, on the other hand you may find that you have a preference.

Yeah, a switch is a good idea for imediate A/B'ing, by the time alot of guys have rewired their speakers they can't really remember what original polarity sounded like (especially if having to solder) & then the "new" sound just "overwrites" the old one.

You might need a fair degree of sustain to really bring the effect to the fore, but I find it's usually quite perceptible.

[woodyc]

David, re: feedback. What you're saying is true about acoustic guitars but I think its a special case that isn't relevant. The phase switch only works at one frequency (I think its for damping a particular mid-bass cavity resonance), only at relatively low volume, and only if you don't move. With electrics you get some level of sustain/feeeback at all frequencies wherever you are. I think the electric scenario is more like the effect of plugging into a Marshall in a guitar shop and hitting a B, and every acoustic in the whole store has its B string ringing. That kind of ringing just takes on the phase of the driving force?

MWJB, Could you be more specific about what to play and what to listen for? Maybe a guitar part from a well-known song where the effect would really be obvious? That would be really helpful. Thanks.

[MWJB]

"MWJB, Could you be more specific about what to play and what to listen for? Maybe a guitar part from a well-known song where the effect would really be obvious? That would be really helpful. Thanks." Just a chord with reasonable sustain should do it, even a single note with enough drive...you're only comparing the phase one way to the other in the same amp, comparing to another amp on a well known song isn't going to help.

If you can't hear the difference don't worry about it. Plenty of amps are inadvertantly wired reverse phase and no one threw them on a skip because of that difference.

It's a way to subtly alter the voice of the amp, you might find itto your advantage you might not? But is usually tangible.

[hasserl]

Like I posted earlier, even different channels of one amp have odd numbers of gain stages, and thus have different phase of the signal. Which channel did you want to be "in phase"? Then there is the issue of using FX pedals, which will again invert the signal, now did you want the amp "in phase" when the effect is engaged, or when it is not? What about when you engage more than one effect? Now what? You think that by simply switching the wires at the output is going to make any practicle difference? It's crazy.

FWIW, I did try this with a Super Reverb. It was relatively easy to switch the leads at the first speaker. Since the others are fed from that they all stayed in phase together. Playing at medium volume, not pushing the amp into distortion, I detected no difference at all. But the theory that makes any traction at all only works when the amp is pushed into distortion, and only when the distortion creates an assymetrical signal.

[MWJB]

I have tried this with dozens of amps.

Forget "in phase"/"out of phase" neither forward or reverse phase is correct/wrong (as long as everything functions normally - I had a test cab loaded with Eminence Alpha 10"s, they hated being wired in reverse - it wasn't subtle either). In the history of some amps they were forward with some speakers and reverse with others.

Phase of channels is only an issue if you are cross patching.

Phase of cabs is important if running multi amp set ups.

Phase of individual speakers in a multi speaker array is important.

I can usually hear the difference in forwards vs backwards speakers in the same amp at moderate volume, it will just be easier if you have good harmonic content to start with.

Because you could not hear a difference does not necessarily mean that there is no difference. It's like the old Confutious riddle, "does a tree that falls in a forest make asound if there is no one there to hear it?"...just because no one can hear it doesn't mean it makes no sound. Even musicians with average hearing (and some with frankly quite damaged hearing) have demonstrated to me that they can hear a difference.

There's no need to waste time theorising or speculating, if you can't hear a difference don't worry about it...if you want to experiment and see whether you get a tonal benefit then try it. Don't be put off by someone telling you that it makes no difference, see for yourself.

[hasserl]

The phase of the channels has to be important, because the phase of the signal from the power amp depends on the phase of the signal into it. If you inject a signal into the front of a Fender amp into the normal channel, and then into the Vibe channel, the resulting output signal to the speakers will be opposite from each of the channels.

So which one do you want the cab to be in phase with?

Psychoacoustics will make you think you hear a difference, just because you want to, or because you think the difference is there. Try to identify the the difference when you don't know which way the speakers are wired, I'm skeptical you would be able to do it.

[Rick Erickson]

Who is putting phase switches on Acoustic guitars? If you move a couple feet relative to your speaker, (or if you turn around)
you will alter your overall "phase". The question of a phase switch on a single speaker amp is more one of matching it to other amps or cabinets. It was probably done for just such technical reasons and mis-interpreted by those who didn't understand the why- kind of like Dylan's song lyrics. (I was just trying to make it rhyme, man...) Professional mixing consoles, particularly recording desks have phase reversal switches on each channel. This can be useful for mixing various amps or mics for tonal purposes or just to make the amp "sit" properly in the mix. I have a friend who used to complain that he had to reverse the phase switch every time a guitarist changed channels on his rather expensive two channel amp or he would change it's position in the mix.

RE

[tbryanh]

FEEDBACK ISSUE

Since the speed of sound is about 1100 ft/sec, if you pluck about an 1100 cycles/sec note on your guitar (about the sixth fret on the G string), the wavelength of the note is about 1 ft.

This means that at about every 6 inches of incremented distance from the speaker, there will be a peak of sound energy in either the positive or negative direction (compressed or expanded air).

If your standing a long distance from the amp so that there is no feedback, and you start walking slowly towards the amp, you will get feedback when you hit the first peak of sound energy that is in phase with your guitar that has enough energy to cause feedback.

If you stop the note, and move six inches closer to the amp and pluck the same note, you will not get feedback.

If your still holding the note, you now have the option of moving either six inches closer to the amp to get feedback or moving six inches away from the amp to get feedback.

Each note on the guitar has its own set of distances where the peaks of sound energy occur.

When you get close enough to the speaker, these sets of distances can be blured.


ASYMMETRY ISSUE

Amplifiers can distort asymmetrically.

Speakers probably can distort asymmetrically.

If you have a clean amp and a clean speaker, the phase of the speaker probably has no effect in either an open back or in a closed back cabinet. (Assuming the cabinet only has one speaker in it)

If you have a dirty amp with asymmetrical distortion and a clean speaker, in a closed back cabinet, the phase of the speaker probably has no effect. In an open back cabinet, the phase of the speaker might have an effect. It might be that one half of the wave sounds better when it exists as compressed air coming out of the front rather than if if it exists as compressed air coming out of the back and reflecting off the wall. . . .

If you have a dirty amp with asymmetrical distortion and a dirty speaker with asymmetrical distortion, the phase of the speaker might have an effect in either an open back or in a closed back cabinet. For example, it might be that the best sound is had when the two asymmetries work together. . . .

…

[MWJB]

"So which one do you want the cab to be in phase with?" Aaaaargh...if you can't hear a difference it doesn't matter....if you can, then they way that sounds best! Usually there are more perrtinent factors deciding which channel you use (Reverb, trem, lead gain, bright, etc, etc,), you're going to use the channel you like the sound of best, irrespective of whether your speakers move forwards or backwards. Lets face it, most folks don't actually know for sure which way their speakers move, it only becomes an issue when using multiple cabs/amps.

"Psychoacoustics will make you think you hear a difference, just because you want to, or because you think the difference is there. Try to identify the the difference when you don't know which way the speakers are wired, I'm skeptical you would be able to do it." I'm sorry, I find that quite insulting. I'm pretty objective. I don't want/not want there to be a difference, I am reporting to you the benefit of my experience...if you can't hear the difference, don't sweat it, but don't presume to tell me what I do & don't hear.

[MattT]

This is extremely easy to test for yourself and I encourage everyone to do it...I was a non-believer until I tried it and then was like...wow.

This has nothing to do with the phase of each speaker relative to the other speakers...it is assumed that all speakers are in phase with each other. This is just about the phase of the entire speaker array relative to the amp output.

Make a reversed-polarity speaker cable...trust me...you'll be keeping it. Set your amp up with a regular-polarity speaker cable and dial it in such that it is just on the edge of feedback (get some OD and volume going)...enough such that you can coax feedback out of the amp with some effort but not so much that it takes off/sings on every note. Now switch to a reversed-polarity speaker cable (don't touch any controls) and play again...you should hear a difference in the feedback...either the amp will now sing on virtually every note or it virtually won't sing at all.

FWIW, in my limited experience an amp that has an odd number of inverting gain stages before the PI needs a reversed-polarity speaker cable and ones with an even number need a regular cable. I recently built a Dumble ODS clone and put the Dumblator FX loop in the amp...but before I put the loop 'in circuit' I wanted to listen to it with no loop (just to make sure the loop was sufficiently transparent). No loop = 4 inverting gain stages and With loop = 5 inverting gain stages. Amp feedsback better with a regular cable and no loop and with a polarity-reversed cable with loop...very repeatable.

hasserl I would do that blind test and I think anyone who actually tries this test would too. But maybe it matters less on some amps (like...almost negligible) than others? I just know on my ODS clone it was VERY apparent.

[woodyc]

MattT, Thanks for relating your experience. Just for reference was the cab open or closed back and what size room?

[MattT]

Hi woody,
It was open-back...not as open as a Fender combo cab but still about 1/4 open (Stone Age OS 2x12 FWIW). Room was about 25'x25', cathedral ceiling (popcorn texture), textured sheet rock walls with non-glossy paint, carpeted, with cloth/fabric sofa and love seat in it as well as some other furniture (mostly wood). IOW, not a particularly live/reflective room...but not totally dead either. I walked around the room and faced different directions and it didn't seem to lessen/intensify the effect any more than it usually does.

Who knows...maybe it's just a Dumble thing. Many of the experienced Dumble builders and users were already very aware of this (of course if you're using a Dumble or D-inspired amp without the Dumbleator then you don't need the reverse-polarity anyway).

[hasserl]

"So which one do you want the cab to be in phase with?" Aaaaargh...if you can't hear a difference it doesn't matter....if you can, then they way that sounds best! Usually there are more perrtinent factors deciding which channel you use (Reverb, trem, lead gain, bright, etc, etc,), you're going to use the channel you like the sound of best, irrespective of whether your speakers move forwards or backwards. Lets face it, most folks don't actually know for sure which way their speakers move, it only becomes an issue when using multiple cabs/amps.

But you said Phase of channels is only an issue if you are cross patching. Which makes no sense. The two channels are out of phase with each other, so the resulting output signal will be out of phase with either channel. If you're going to set the phase of the cabinet to match the amp, which channel are you going to match it to? That's the question. For those that only use one channel, the answer is easy, for those that use both it's not.

But the point of the question, while based on practical application, is really to point out the futility of trying to match the phase of the cab with the phase of the amp, because the phase of the amp is constantly changing, depending on which channel is used, what effects are used, and I still say it all starts with the signal from the guitar. How the pickups are wired, and even how you pick or strum the strings. If you pick a single note with a down stroke, then you pick the same note with an upstroke, is the phase of the signal the same or opposite? I think they will be opposite. So which one did you want the cab to be in phase with, your upstroke picks or your downstroke picks? Or you upstroke picks on which channel? Or your downstroke picks on which channel with which effect pedal (or combination) turned on? Go ahead, you're going to decide under which circumstance you want the cab to be in phase with the amp. Go for it.

"Psychoacoustics will make you think you hear a difference, just because you want to, or because you think the difference is there. Try to identify the the difference when you don't know which way the speakers are wired, I'm skeptical you would be able to do it." I'm sorry, I find that quite insulting. I'm pretty objective. I don't want/not want there to be a difference, I am reporting to you the benefit of my experience...if you can't hear the difference, don't sweat it, but don't presume to tell me what I do & don't hear.

And the usual response is indignation at being challenged. That's not my intent. You, as well as I and everybody else here, are influenced by things that we really cannot control. The science, at least to my understanding of it (and I'm more than willing to be swayed with a logical explanation), says this should not be an issue, that you couldn't possibly control the phase of the signal, and that there should be no difference which way the speaker cable is wired. You say there is. Fine, prove it. Don't be insulted, just take the challenge and set up the experiment that will lay to rest whether the phenomenon is genuine or not.

[hasserl]

hasserl I would do that blind test and I think anyone who actually tries this test would too. But maybe it matters less on some amps (like...almost negligible) than others? I just know on my ODS clone it was VERY apparent.

At this point I'd settle for just some sound clips. Stick an SM57 in front of that bad boy, let someone else switch the cable, without you knowing when/if they changed it, while you play. Then post the clip here so we can all hear it for ourselves.

[MWJB]

"Which makes no sense. The two channels are out of phase with each other, so the resulting output signal will be out of phase with either channel. If you're going to set the phase of the cabinet to match the amp, which channel are you going to match it to? That's the question. For those that only use one channel, the answer is easy, for those that use both it's not." If you are using one amp, what does it matter which channel plays forward or backwards...there is no "matching" unless you are using multiple amps/cabs...I don't understand what you mean by "matching", the amp either plays forwards or backwards...that's it. Both work, both will sound OK, just a little different.

Yes, the phase changes with channels, gain stages & other factors...but the cab is always "in phase" with the amp, just out of phase with specific stages. It is only out of phase when other influences dictate (multiple amps, cabs wired differently to each other). This seems to be the apart that you are overlooking.

"Don't be insulted, just take the challenge and set up the experiment that will lay to rest whether the phenomenon is genuine or not." How can I not be insulted? People pay me to work on their amps because they trust my ears & judgement, I have worked hard & long, spending many many hours performing critical hearing tests, devloping my hearing skills (the more you do the better you get) and you are sitting thousands of miles away, with no first hand experience of my work, or having sat in on many of the polarity tests that I have performed for customers in their "final fittings" for an amp service/mod", telling me I can't hear what I hear? Indignant...ya think?

What exactly does "the science" say on the specific subject of a given speaker in a given amp sounding different, when the cone fires forwards when a positive signal is applied, compared to backwards when a positive signal is applied? Why do you need an explanation, what's wrong with a practical test?

Prove it? How do you intend to prove what I can and can't hear? Why do I need to waste my time proving that there's a difference...I don't need to prove that the wind blows, the rain falls, or the sun rises either.

Why do you describe it as a "phenomenon"?

You have tried it once and not found a marked difference, fine, that's your experience...you could just say that, rather than questioning my integrity and proclaiming in a rather grandiose manner that you have "science" on your side.

If you said that you preferred a specific brand of tube or speaker...I'd have to believe you, even if I didn't share that opinion...I wouldn't suggest that you prove it.

[MWJB]

If you can't hear the effect in the room, why do you think that you will hear it better after being amplified, recorded, compressed, played back through the typical PC speakers?

YOU prove it doesn't make any difference.

[MattT]

hasserl,
Can I just make a clip (or two) that compares them? It would be apparent enough in a clip.

Of course, now I'll have submit to the ridicule of my playing and my crappy sounding build.:o

hasserl, you and I were typing at the same time but I wanted to add that I don't have an explanation for it...I never believed until I tried it. I just know that when I tried it that it wasn't subtle...it was very noticeable.

And as far as the imperfections of humans, our biases, and how we can be influenced by so many factors and none of us are immune...that's my line! :)

[hasserl]

I've got to tell you, I'm pretty much at a loss here. It's am getting to the point where you are making no sense at all. Let's try to iron out exactly what the issue is.

If you are using one amp, what does it matter which channel plays forward or backwards...there is no "matching" unless you are using multiple amps/cabs...I don't understand what you mean by "matching", the amp either plays forwards or backwards...that's it. Both work, both will sound OK, just a little different.

It sounds like you're making my argument here. We are not talking about multiple amps, cabinets, or speakers being in phase with each other. We are talking about a single amp connected into a single cabinet (one speaker or multiple speakers in phase with each other). You say there is a difference between having the speakers connected to the amp one way verses the other. If you're talking about multiple amps or speaker cabinets then we're talking about different things here. I thought the issue was ONE AMP, into ONE SPEAKER.

the phase changes with channels, gain stages & other factors...but the cab is always "in phase" with the amp, just out of phase with specific stages.

This makes absolutely no sense. If the cab is always in phase with the amp, why would it make any difference which way the speakers are wired?

It is only out of phase when other influences dictate (multiple amps, cabs wired differently to each other). This seems to be the apart that you are overlooking.

Again, we are talking about ONE AMP only, not the relationship between two or more amps. ONE AMP & ONE SPEAKER. Right?

You say there is a difference in sound between having the speakers wired one way verses the other (there are only two ways, tip to positive/sleeve to negative, or tip to negative/sleeve to positive). Have I've described the topic correctly? Because if I haven't, then we are arguing different things and we might as well drop it here. But I do believe I've described what the OP was about.

Now, assuming we are talking apples and apples here (I realize the risk I take assuming something, I'll live dangerously here):

How can I not be insulted? People pay me to work on their amps because they trust my ears & judgement, I have worked hard & long, spending many many hours performing critical hearing tests, devloping my hearing skills

That doesn't make you immune to the power of suggestion. If you think you are immune to it, you are wrong. You are susceptible to it just as I and everyone else here is.

What exactly does "the science" say on the specific subject of a given speaker in a given amp sounding different, when the cone fires forwards when a positive signal is applied, compared to backwards when a positive signal is applied? Why do you need an explanation, what's wrong with a practical test?

The science says that trying to control when a positive signal is applied to the speaker is futile. I gave you multiple examples of why. You haven't given one rational explanation for any of those examples. You have absolutely no idea when you pluck a note on the guitar whether the fist impulse that hits the speaker will be positive or negative. If you think you do, please explain it. I'm thick headed, I need help here. With all of the variables I put out above, how is it possible that you could control whether the signal out from the amp is either positive or negative? Please, explain.

Prove it? How do you intend to prove what I can and can't hear? Why do I need to waste my time proving that there's a difference..

Why you would do it is because you are the one making a claim that defies logic. How you would do it is you would conduct a series of blind tests where you would play a guitar into an amp while someone else switches the phase of the speaker cable. You would not know which direction the phase was, or if it was even switched. If you can consistently identify the position or phase of the speaker cable you will have proven there is an audible difference that you can hear and identify. You'll have proven the phenomenon is real.

You have tried it once and not found a marked difference, fine, that's your experience...you could just say that, rather than questioning my integrity and proclaiming in a rather grandiose manner that you have "science" on your side.

I don't know how I've questions your integrity, or how I'm being grandiose. I'm merely making an argument against what you've claimed. I've given multiple examples of why what you claim should not be true, you haven't given one explanation of why it is.

[hasserl]

If you can't hear the effect in the room, why do you think that you will hear it better after being amplified, recorded, compressed, played back through the typical PC speakers?

YOU prove it doesn't make any difference.

The scientific method requires those making a claim to prove it, not asking the skeptic to disprove it. If the difference exists why should we not be able to hear it?

hasserl,
Can I just make a clip (or two) that compares them? It would be apparent enough in a clip.

Of course, now I'll have submit to the ridicule of my playing and my crappy sounding build.:o

Matt, the problem is, you'll know how the cable was set and it will influence your playing. You have to have someone else making the switching for you, it should be done so that you do not know when or even if they have switched the cable, and in fact there should be instances of where they do not switch it when you think they might have. You need to make it as close to a blind test, or even double blind, as possible.

[MattT]

So you would 'trust' an audio clip of this but you won't take my word that I can hear a difference? Obv I could 'fake' any audio test just as easily as I could lie...I have no reason to do either though. Or are you saying that I'm 'imagining' this difference and when 'put to the test' that I really couldn't hear the difference? Either I'm mistaken or I'm lying...or maybe the third option...maybe I really do hear the difference. And it's not a matter of; "Well I can hear a difference...if you can't it's because you have a tin ear." Nothing of the sort. If you have tried it and could not tell a difference then maybe it was not an issue with that amp...I've only tried it with my ODS clone and the difference was apparent.

I'm the one that's always telling everybody else how imperfect and biased we humans are. I'm fully aware of it and try use that information to make sure I don't make these kind of mistakes. There are some things that are apparent enough that I don't need a double-blind test.

Crap...now I gotta train the dog how to swap a speaker cable.:D

[hasserl]

Matt, I'm skeptical that there is an actual real difference. I'm not challenging your integrity, I'm not saying you're imagining things. I'm certainly not implying you would intentionaly alter the sounds. I do say that we are influenced in many subtle ways, sometimes we belive we hear, see, and even taste things that are not there.

As an example, I saw an experiment on TV where people were blindfolded and then given some plain unflavored yogurt, but they were told it was flavored with flavors like Strawberry, Lemon, & Orange, and they were asked to grade the taste of the yogurt. Afterwards they removed the blindfolds and learned the yogurt was unflavored. Every one of the subjects would have sworn that they were tasting the flavor that was told to them. Were they lying? No, of course not. The power of suggestion is stronger than you might think. I've seen wine tests where wine conisoures were given cheap wine and told it was very expensive, then they were given expensive wine and told it was very cheap, they reacted just as they were told, the power of suggestion overwhelmed their sense of taste.

I'm just saying that to do this right have someone else make the switches of the cable so that you don't know what they're doing. Don't you agree that would make a more interesting and beliveable result?

[woodyc]

Well, UPS just came with my DPDT footswitch. So far I've tried polarity reversal clean and cranked with a 65 Pro Reverb. I tried the amp with its combo speakers, and also with a 64 Bassman 2x12 closed back cab.

On the big questions of low-end and tone, so far I can't hear any difference whatever.

There IS a feedback difference, but personally I think its insignificant.

It shows up only if you have a note that is feeding back weakly or on the edge of feedback, and you push the phase switch, you can either increase or kill the feedback. This is basically the same deal as what happens with i.e. the feedback switch on a Fishman piezo preamp. You can't say that one polarity is better than the other unless you are only talking about a certain amplitude note at a certain distance from the amp.

Another interesting feedback effect is that if you have a note feeding back strongly, and you push the phase switch, you can actually hear the string change phase. It takes a second or so. During that time there is a slight lull in the level. However apart from the transistion, the feedback sounds the same with either phase.

Finally one weird procedural note. Because of the feedback phase thing, you have to stop playing when you switch. I was initially playing over the switching and convinced myself the tone was changing. It turned out it was just the phase of the ringing-note-feedback getting out of synch and then synching back up. If you stop playing for a few milliseconds during the switching, you don't get that effect at all.

[Alex R]

Finally one weird procedural note. Because of the feedback phase thing, you have to stop playing when you switch. I was initially playing over the switching and convinced myself the tone was changing. It turned out it was just the phase of the ringing-note-feedback getting out of synch and then synching back up. If you stop playing for a few milliseconds during the switching, you don't get that effect at all.

Aha...

[MWJB]

"The scientific method requires those making a claim to prove it, not asking the skeptic to disprove it. If the difference exists why should we not be able to hear it? " The scientific method requires a controlled, unbiased test (which would appear to exclude you and I from conducting the test). There is no "we" the question is whether "you" can hear it. If you can't hear it in the room, why would you hear it any better in a recording with a number of processes that skew the original sound?

Perhaps science can also prove why different cables with the same pf/ft and resistance between conductors sound different, what my faviourite brand of preamp tube is, how many sugars i like in my tea?

You build tube amps because you like the sound they make, you will set them up according to your taste...do you need science to "prove" how much plate voltage you like or do you arrive at that by ear?

For someone who is involved in a hobby incorporating so much subjectivity you seem bizarrely dependent on "proof".

"This makes absolutely no sense. If the cab is always in phase with the amp, why would it make any difference which way the speakers are wired?" How can the speakers be out of phase with the entrire amp, the speakers would cancel the signal from the amp. Amps can be out of phase with each other, channels can, speakers can BUT (now listen very carefully...for the last time) your cab is not out of phase with your amp...we are talking about a difference in harmonic content depending on whether the speaker moves forward with a positive signal, as opposed to moving backwards with a positive signal.

[MattT]

Just to be clear...I'm not saying there is a change in tone per se...just that it feedsback better one way vs. the other on my ODS clone. And as far as 'adjusting' my playing for each polarity...I wasn't really 'playing'...I was just lightly touching/hammering a note and letting it ring out...sometimes taking off sometimes not. I was just listening for which polarity had more feedback...if any...and my expectation was for there to be no difference. But if there was a difference...I had no idea which way would feedback better. That was part of the purpose of the test...not only to see if there was a difference but if so...which way sounded best.

So I think I was as unbiased as possible going into it...but just by virtue of doing the test in the first place implies that there was some sort of expectation...but I often perform tests like this just so I can honestly say; "I tried it and it made no difference."

[hasserl]

The scientific method requires a controlled, unbiased test (which would appear to exclude you and I from conducting the test).

No it doesn't. You obviously are not familiar with scientific testing and experiments. Nobody is ever without influences and prejudices. That's why you set up experiments to eliminate the subjective and concentrate on the objective. Effective experiments and tests should have good reproducibility and repeatability.

There is no "we" the question is whether "you" can hear it. If you can't hear it in the room, why would you hear it any better in a recording with a number of processes that skew the original sound?

See, there yo go with the typical argument of "you can't hear it but I can", that shows how weak your argument is. You haven't provided any explanation for any of the reasons I pointed out why swapping the speaker wires would make any difference, you just fall a tired old argument.

Perhaps science can also prove why different cables with the same pf/ft and resistance between conductors sound different, what my faviourite brand of preamp tube is, how many sugars i like in my tea?

You build tube amps because you like the sound they make, you will set them up according to your taste...do you need science to "prove" how much plate voltage you like or do you arrive at that by ear?

For someone who is involved in a hobby incorporating so much subjectivity you seem bizarrely dependent on "proof".

This is funny, you made a claim that something exists that logic says should not exist. When I challenged you on it, you feigned indignation and asked what science there is, so I gave it to you. Now, instead of explaining why that science is wrong you instead try to make fun of it and fall on the subjectivity of the hobby. Just goes to show the weakness of your argument. At least the guys on The Gear Page gave me good technical reasoning that I could even argue on their behalf if I had to. You've got nothing, NOTHING. "I hear it, if you don't too bad". You can't explain it, you can't prove it, but you believe it and are insulted if someone challenges you. Sounds like religion to me.

How can the speakers be out of phase with the entrire amp, the speakers would cancel the signal from the amp. Amps can be out of phase with each other, channels can, speakers can BUT (now listen very carefully...for the last time) your cab is not out of phase with your amp...we are talking about a difference in harmonic content depending on whether the speaker moves forward with a positive signal, as opposed to moving backwards with a positive signal.

OK, maybe the term phase is throwing you off. It's actually polarity that we're dealing with. But the effect is the same. You're convinced that having a positive signal move the speaker forward makes the cab sound better than a positive signal moving the speaker backward. If that's your only point, OK. Whatever. That's not the point of this whole thread and it is meaningless. Now you listen very carefully. My point is that the positive/negative swing of the output signal from the amp is constantly changing and only under very limited circumstances would things ever line up so that a pick or strum of the guitar strings would result in the initial swing of the output signal always being positive. In the real world the conditions change constantly and you cannot control whether the initial swing of the output voltage is positive or negative, it is what it is, due to everything from the initial note generated at the pickup, to any effects unit the signal is run thru, to the number of gain stages in the preamp. If you only play with a constant single picking motion, if you use no effects, if you have no channel changes, you might be able to set up your rig so that all output signals always start with a positive swing. But that is not practical in the real world, at least not in mine.

And that is the only thing that matters in this conversation, whether the polarity of the speaker wires causes the initial swing to move the speaker forward or backward. Otherwise the signal to the speakers is just an ac signal swinging at a frequency of around 100 times per second to several thousand times per second and a speaker vibrating at that same frequency. A pick of the string might start with the speaker moving forward, or it might start with the speaker moving backwards, it all depends on the things I've mentioned above (including which direction you've plucked the string, or whether the pickup is reverse wound reverse polarity).

[woodyc]

I tried a couple more amps, a Marshall 1987x and a Vox AC30CC2. Here’s a pic with the new phase switch in the foreground (which cost $43 with the cables and all.)

http://www.members.aol.com/wsjcrane/polarityswitch.jpg

As before at any particular location if you are on the edge of feedback there is an audible tone effect. But I haven’t found that one polarity produces either a better tone or more feedback generally. Also I have not found any evidence supporting Gerald Weber’s low end claim.

Alex R, I agree about the “Aha.” This is a very hard listening test. I can see a number of ways people could do what they think is a fair test and end up with a preference for one polarity.

Hasserl, I think you’re right about the picking technique, pickup polarity, effects, et cetera. It seems like the belief that speaker polarity matters creates a whole bunch of new things to worry about.

[Enzo]

OK, this is like the old AMpage now. This thread has become less about speaker phasing and more about the argument itself. A pissing contest in other words. The argument has become about itself. I'll wait in the hallway.

[pdf64]

Hey woodyc, I would be wary of switch the speaker with the amp putting out full power, as there will be a momentary open circuit while the contacts flip over, which will induce a big back emf across the OT primary, which could cause arcing over in the OT or tube bases. Just a note of caution, I'm not sure if that's what you are doing or not - Peter

[JC@]

...Aaaaargh...if you can't hear a difference it doesn't matter....if you can, then they way that sounds best!

...if you can't hear the difference, don't sweat it, but don't presume to tell me what I do & don't hear.

I can hear a clear difference.
I can hear a difference in aluminium frame speakers over steel sheet frame speakers.
To me phasing does matter a lot in some speakers, and not so much in others.
I've found speakers that will pull a lot better than push; let me explain myself a little better, in an unknown situation, I always use a cell battery, a weak 9volt one works because it is just a second, and I like to mark as "possitive" the pole that pulls to the frame and magnet direction. Then sometimes I reverse the polarity to see if it "pusshes" in the same ammount.

And I like pulling for guitar, and pushing for bass guitar, but that may well be just a matter of personal taste.