Basic speaker polarity question

[rydia is hot]

In a combo with 4x10s (a Fender Super Reverb), if I want to give the reverse polarity thing a shot, can I just reverse the wires coming from the speaker output that connect to the first speaker?

Thanks in advance for your patience with this elementary inquiry :D

[phsyconoodler]

Yes,just follow the wire from the speaker jack to the speaker and reverse those. Be warned: it may make the amp squeal like a stuck pig.

[TD_Madden]

Yes,just follow the wire from the speaker jack to the speaker and reverse those. Be warned: it may make the amp squeal like a stuck pig.

Never heard of that, although I know misconnecting the OT leads to the output tubes can do it.

[LPMark]

Reversing the polarity of all speakers won't make it squeel, it won't have any effect...
unless you play it with a second amp at the same time.

I know Gerald Weber say's forward playing amps sound better, and that's just plain silly!

As the signal flows through the amp, each gain stage inverts the signal.
Amps with an even number of gain stages play "foward"
Amps with an odd number of gain stages play "backward"
Is that why different amps sound different? NO

Fender blackface amps like your Super Reverb have one chanel with an odd number of gain stages and one with an even number so depending on which one you plug into you are reversing the phase of the speakers relative to the guitars output.

But by all means do it if you want.

Mark

[TimmyP]

It will indeed sound different - it will have more attack when the polarity is correct. If you play loud, it will also have better sustain. If you play stupid loud, the difference in sustain will be large.

[LPMark]

It will indeed sound different - it will have more attack when the polarity is correct. If you play loud, it will also have better sustain. If you play stupid loud, the difference in sustain will be large.

And the evidence to support that argument is???
That's the beauty of opinions- they don't need to be supported with facts. Ya hears what you expect to hears.
and "These amps go to 11"

As I said, by all means try it- but do it scientifically, in a blind test with a friend switching repeatedly so you don't know which one is which [turn standby off while unplugging] and document the results.
You can wire a second plug from the speakers but wire it opposite polarity of the original, and leave them both connected to the speaker but only plug one into the amp at a time and insure that
the loose one doesn't short to the chassis, then you can A/B test quickly.

If indeed the difference is at all noticeable your results should show close to 100%. of the time you can tell the difference.... I'll take that bet any day of the week.

Mark

[Marshamps]

I would think it would depend on the amount of feedback that a player uses to create his tone. If the air is moving out of phase with the strings vibration, i could see it making a subtle change in the sustain at very least.
I can tell you just having a ceiling fan on in a room changes the tonality of the Opto vibrato so i'm not surprised out of phase airwaves can change the feedback or sustain sentsitivity of an amp.

[pdf64]

As most 'acoustic' amps etc have a signal inverion switch intended to supress feedback, is there a gap in the market for a basic signal inverter, sold as a 'feedback enhancer' pedal?

[LPMark]

Absoloutly!!!!
There's always a market for magical mojo inducing devices.

Acoustic phase relationship ['through air] is governed by: Wavelength [reciprical of frequency X velocity of sound] and distance from the source.

Speed of sound at sea level is roughly 1200 feet per sec
At the pitch of 'A' 440 [440 HZ] you have 440 cycles per sec
So : 1/440 = .00227____ multyplied by 1200 = 2.7 or a wavelength of 2.7 feet
An octave lower: 'A' 220 = 5.2 feet ... 'A' 110, low A on the guitar is 10.4 feet.

As you move closer or further by half the wavelength, you move through the opposite phase. This applies mainly to sine waves. There is less phase correlation as harmonics increase and the guitar has much more complex harmonics, then there's chords.

So whether you are in phase or out depends on the pitch, the distance, and the purity of tone [harmonic content] and not the polarity of the speakers. That is why you will never see speaker polarity denoted on any schematic: the engineers never deemed it relevent and it has no more effect on tone than whether the labels on the speakers are right side up or upside down

And how do you know if your guitars pickups are positive phase or reverse? Sounds like Spinal Tap again. Over the years PU's have been wound both ways and it is irrelevent as long as they are all the same on the guitar.

Phase reversal switches are meant for instruments and mics which are stationary with a fixed distance from the speakers, then you can set it to whichever position cancels the feedback. If one position was always the correct one then that's where it would stay and there would be no need for a switch.
As everyone knows feedback on a runaway ringing mic can be instantly stopped dead just by moving the mic. Mic feedback is more sinusoidal becaue of the nature of the acoustic link so a phase switch can be very effective.

This is why electic guitar feedback will usually settle to what sounds like a single pitch as the harmonics fall away and the loop renforces the fundamental.

[scottl]

Mark... It makes a difference. You don't need a blind A/B. At least with Dumble style circuits with the OD on. Much better feel and feedback/sustain when the speakers are forward firing.

I have demonstrated it dozens of times with witnesses. It works regardless of distance from amp too.

Unless you have tried it, with some volume and this kind of OD (big assymetrical wave form btw), you are just blindly commenting on that you have no experience with.

Pickups do matter. My Dimarzio's liked backward wiring as they were not the same polarity as my other humbuckers....

Maybe the speaker and cabinet dampening matters in this situation. Also, keep in mind the strong assymetrical leading edge of the Dumble OD waveform. Hard to tell, if at all on the clean channel. OD is easy.....

Reversing the polarity of all speakers won't make it squeel, it won't have any effect...
unless you play it with a second amp at the same time.

I know Gerald Weber say's forward playing amps sound better, and that's just plain silly!

As the signal flows through the amp, each gain stage inverts the signal.
Amps with an even number of gain stages play "foward"
Amps with an odd number of gain stages play "backward"
Is that why different amps sound different? NO

Fender blackface amps like your Super Reverb have one chanel with an odd number of gain stages and one with an even number so depending on which one you plug into you are reversing the phase of the speakers relative to the guitars output.

But by all means do it if you want.

Mark

It will indeed sound different - it will have more attack when the polarity is correct. If you play loud, it will also have better sustain. If you play stupid loud, the difference in sustain will be large.

And the evidence to support that argument is???
That's the beauty of opinions- they don't need to be supported with facts. Ya hears what you expect to hears.
and "These amps go to 11"

As I said, by all means try it- but do it scientifically, in a blind test with a friend switching repeatedly so you don't know which one is which [turn standby off while unplugging] and document the results.
You can wire a second plug from the speakers but wire it opposite polarity of the original, and leave them both connected to the speaker but only plug one into the amp at a time and insure that
the loose one doesn't short to the chassis, then you can A/B test quickly.

If indeed the difference is at all noticeable your results should show close to 100%. of the time you can tell the difference.... I'll take that bet any day of the week.

Mark

[Tone_Terrific]

Search back for posts by Kimock on this topic.
Regardless of what you, or I, or anybody else, may think or hear, I would NOT bet the farm against him any day of any week!

[kimock]

This is why electic guitar feedback will usually settle to what sounds like a single pitch as the harmonics fall away and the loop renforces the fundamental.

Or reverse the loop characteristics by flipping the speaker phase and cancel the fundamental and split the single pitch into harmonics.
You answered your own question there chief.
The output is connected to the input.
Acoustically, between the guitar and the amp is the only possible place to get positive feedback.
You're either getting it, and getting more of everything, or you're not.
And getting less. . .

Speaker polarity is one way to get a handle on that.

[LPMark]

Or reverse the loop characteristics by flipping the speaker phase and cancel the fundamental and split the single pitch into harmonics.
You answered your own question there chief.
Speaker polarity is one way to get a handle on that.

This statement is contrary to my explaination of acoustic phase correlation [Phase = wavelength/distance] so I assume you disagree with it or you didn't understand it there chief.

When I say the acoustic loop reinforces the fundamental, I am speaking of the fundamental of the acoustical RESONANT FREQ which is usually octaves higher and more sinusoidal than the original string vibration.

Mark... It makes a difference. You don't need a blind A/B. ....
I have demonstrated it dozens of times with witnesses. It works regardless of distance from amp too.

When you say you don't need a blind A/B test this implies you have NOT done a blind scientific test but a "Demonstration" by your words.
A demonstration by its nature implies a point of view which you are trying to convey or convince.

Scotti, I will concede that in the case of a grossly asymetrical waveform it COULD be affected by polarity, but this is greatly complicated by the acoustic link etc... and doesn't apply generally and not specifically to the original question which involved a Fender SR which as I previously stated will have different phase relationship of input to output depending on which chanel you plug into.

I am not so much trying to say everyone who believes in the 'Speaker Polarity thing" is wrong, I'm saying the science DOES NOT support it.
If ayone has a scientific argument to contribute I am all ears.

Mark

[kimock]

This statement is contrary to my explaination of acoustic phase correlation [Phase = wavelength/distance] so I assume you disagree with it or you didn't understand it there chief.



You don't know what you're talking about.

[phsyconoodler]

So here's a very basic question for you: " why bother labeling speakers + or - at all?
Speaker manufacturers know something that all the naysayers don't.
Maybe in your bedroom you can't notice a difference but live at full song.....

I'm putting my money on Mr. Kimock. I also play live too.

[Tone_Terrific]

So here's a very basic question for you: " why bother labeling speakers + or - at all?


That info is to ensure that when wiring multiple speakers you can keep the polarity the same.
There is no doubt that speakers need to be in phase with one another.

[LPMark]

You don't know what you're talking about.

Ahh, now that's a scientific argument!!!

Kimock, I think youv'e made it very clear that YOU don't know what I'm talking about.
This is basic Physics

If you disagree with me, how about a coherrent scientific rebutal?

Mark

[kimock]

Ahh, now that's a scientific argument!!!

Kimock, I think youv'e made it very clear that YOU don't know what I'm talking about.
This is basic Physics

If you disagree with me, how about a coherrent scientific rebutal?

Mark

Mark, I've got the phase angle bit, thanks.
This is very basic, yes, and weirdly non-obvious for some reason, but the answer to the question "Is there an audible effect to changing speaker polarity with an electric guitar and amp?" is yes, there is an audible effect.

The explanation for that you already know, is "feedback".
It's not a phase angle issue, that stuff is all ballistic for our purposes, it's a loop characteristic, and it's either positive or negative.
That's the whole deal, the guitar and amp are both sound sources, the output is connected acoustically to the input, the output either drives the input up or down.

This is well established, you've already mentioned one example yourself as feedback summing to the fundamental.
If you've got energy sufficient to sum, you've got energy sufficient to cancel, which you could demonstrate for yourself with your own guitar and amp and some means to flip the phase or polarity.

The reason I say you don't know what you're talking about is you've failed to make the observation that there is an audible effect to speaker polarity under these conditions, you're using random non-applicable "science" to defend that failure, and you've already gotten the answer but failed to realize it.

Just think about it for a minute, you're smart, you'll get it.

[LPMark]

OK,
I concede that there MAY BE an audible effect to changing speaker polarity in some scenarios though I remain solidly unconvinced.
I suppose I will have to experiment with some of my amps.

I'm not sure what "answer" you are refering to with "you've already gotten but failed to realize it."

The point I was getting at about feedback is this:
I understand that you are saying:

reverse the polarity-
reverse the phase--
change the dynamics of the feedback.
Absolutely, however, in this scenario you must consider that: the distance from the source/wavelength[frequency]-- relationship is a major variable and cannot be disregarded.

example: I play "A" 440 on the guitar[2nd string 10th fret]-- establish the "sweet spot" for good sustained feedback-- switch speaker polarity, I now need to be half a wavelengths difference in distance up or back to make a fair analysis.

Some real world numbers.
440 hz = .0027sec.... X [speed of sound] 1100 ft/sec = 2.9ft wavelength.
Assume positive going guitar signal out, positive speaker polarity,
360* phase angle [positive sumation] occurs @ 3ft, 6ft, 9ft etc.....
Speaker polarity reversed, 4 1/2ft, 7 1/2ft, 10 1/2ft........

Bottom line, if it works for you do it.

Mark

[kimock]

OK,
I concede that there MAY BE an audible effect to changing speaker polarity in some scenarios though I remain solidly unconvinced.
I suppose I will have to experiment with some of my amps.

You can see the diff on any software that displays waveforms.

I'm not sure what "answer" you are refering to with "you've already gotten but failed to realize it."

It's just feedback. I struggled mightily with trying to overcomplicate too, but it's just feedback.

The point I was getting at about feedback is this:
I understand that you are saying:

reverse the polarity-
reverse the phase--
change the dynamics of the feedback.
Absolutely, however, in this scenario you must consider that: the distance from the source/wavelength[frequency]-- relationship is a major variable and cannot be disregarded.

Yup.

example: I play "A" 440 on the guitar[2nd string 10th fret]-- establish the "sweet spot" for good sustained feedback-- switch speaker polarity, I now need to be half a wavelengths difference in distance up or back to make a fair analysis.

Exactly. As long as you're not two places at once, flipping the speaker polarity flips the system polarity.

Some real world numbers.
440 hz = .0027sec.... X [speed of sound] 1100 ft/sec = 2.9ft wavelength.
Assume positive going guitar signal out, positive speaker polarity,
360* phase angle [positive sumation] occurs @ 3ft, 6ft, 9ft etc.....
Speaker polarity reversed, 4 1/2ft, 7 1/2ft, 10 1/2ft........

Bottom line, if it works for you do it.

Mark

Node, anti node. It's on the string too, but if the above is still out of reach, you're not ready for what's going on back at the guitar!!:omg

[LPMark]

Exactly. As long as you're not two places at once, flipping the speaker polarity flips the system polarity.

Exactly. well I would say flips the phase WITHIN the system which changes the point in space of the acoustic nodes-anti nodes, they are shifted by 1/2 wavelenth. Now the feedfack sweet spots have moved
by that factor and to make an assesment of feedback you must factor that in. All I'm say'n
The loop is established through the acoustic link, we can alter that by moving.


Node, anti node. It's on the string too, but if the above is still out of reach, you're not ready for what's going on back at the guitar!!:omg

Now you're complicating things. String vibrational nodes will always be fractional division of vibrational length during feedback and a change in regenerative phase angle can cause them to shift [octaves and harmonics] but that's a whole other discusion.

Now you can have the last word cause I think it's time for this thread to end.

Mark

[kimock]

Now you can have the last word cause I think it's time for this thread to end.

Mark

#12

Bump. . .:munch

[LarryN]

In a combo with 4x10s (a Fender Super Reverb), if I want to give the reverse polarity thing a shot, can I just reverse the wires coming from the speaker output that connect to the first speaker?

Thanks in advance for your patience with this elementary inquiry :D

Better yet, see if you hear a difference. I didn't think much of the idea when I first heard it, but after trying it, I can hear it. I can hear more to the note. I mainly did it on the rev/vib channel of Fenders in the black/silver era. Other amps I do by ear. Some things are not as immediately perceived. This stuff adds up. One thing I'm unsure about is how the ground to the speaker frame effects the whole deal. Some speakers have that.

[kimock]

Better yet, see if you hear a difference. I didn't think much of the idea when I first heard it, but after trying it, I can hear it. I can hear more to the note. I mainly did it on the rev/vib channel of Fenders in the black/silver era. Other amps I do by ear. Some things are not as immediately perceived. This stuff adds up. One thing I'm unsure about is how the ground to the speaker frame effects the whole deal. Some speakers have that.

I don't think you need to consider anything but what's happening acoustically to get your head around it. The string vibrates, the air shakes, you add a little energy or you take some away.
The string is going in different directions over the neck and bridge pickup locations with even a little whack, so unless you have some scheme to chase that, you'll only ever compromise one pickup to dial in the other.
In case you were wondering about those single coils. . .;)

[LarryN]

I don't think you need to consider anything but what's happening acoustically to get your head around it. The string vibrates, the air shakes, you add a little energy or you take some away.
The string is going in different directions over the neck and bridge pickup locations with even a little whack, so unless you have some scheme to chase that, you'll only ever compromise one pickup to dial in the other.
In case you were wondering about those single coils. . .;)

That's what I was thinking. If the impulse is coming at you rather than away from you on attack, your ears and guitar are going to be more stimulated. It really is that simple to me. The main thing is I can hear it.

Funny how heated the concept gets. :mob

What makes it even easier to visualize is how dramatic two out of phase speakers sound, which is a purely acoustic phenomena, from two speakers moving in opposing directions.

Someday I'll try the effect from different pickup positions.

[zzmoore]

I did not realize Audio phase was......well....audible.
You guys can hear that.?
What would be the difference.?

[LarryN]

I can't be any more descriptive that what's in my posts. Try it and see if you can hear it. It takes a little more careful listening. I'm not saying it's easy to hear, but I've been using the "electric guitar and amp components" part of my hearing for many years, so it just might be an acclimated kind of listening. Most people can do this with time. I haven't yet tried it with different pickups on the same guitar, so there's more to do for me.

[phsyconoodler]

Try it with a bass amp cabinet.They do not like to be reverse phased.The cones move a lot further than a guitar amp speaker does and the phasing is much more prevalent.
I think the reason it's less noticeable is because the average guy doesn't get those guitar cones cranking in and out as much as a bass amp does.
high volume stage amps are very sensitive to the speaker direction of phase.
As a repair tech I always check the phase of a cabinet when loading new drivers.

[LarryN]

Now we are getting somewhere! Blame Canada.

[zzmoore]

I understand the importance with multiple speakers......to choreograph the timing
But otherwise.....the cones move in and then they move out.
What happens to create a difference, in sound, when phase is reversed.?
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

[LarryN]

I understand the importance with multiple speakers......to choreograph the timing
But otherwise.....the cones move in and then they move out.
What happens to create a difference, in sound, when phase is reversed.?
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

The impulse moving towards you from the speaker on attack sounds more positive to the ear.

[kimock]

But otherwise.....the cones move in and then they move out.

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

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".

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.