Speaker polarity ?

Discussion in 'Shock Brother's DIY Amps' started by Mfa88, Aug 5, 2020.

  1. elpico

    elpico Tele-Afflicted

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    Well back in guitar world it's still a fact that neither guitar pickups nor guitar amps have any kind of consistent or "correct" phase. And even if they did playing a different note or stepping a few feet away would change that phase relationship anyways. Some players have been known to walk around and tape off spots on the stage where certain notes sustain best so they can play a certain solo there, but that's about as much as you can do
     
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  2. tubegeek

    tubegeek Friend of Leo's

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    Some say yes, some say no on that. I can't tell someone else what they hear, that's subjective.

    In any case if anyone wants to say the perception is symmetrical, that's a point that can certainly be argued. But to say the wave form is symmetrical, I'm not sure how that's supported by what I know.

    There's yet another consideration - is the wave form the sound or the perception? A pressure wave - in my opinion, anyway - isn't a sound until someone's brain processes it. So maybe only the perception matters.
     
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  3. elpico

    elpico Tele-Afflicted

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    You guys are dragging a debate from the world of hifi into an unrelated situation where it has no relevance.

    Hifi amps are sound reproducers.

    Guitar amps are sound creators.

    The goal of a hifi amp is to perfectly recreate the pattern of vibrations the original instrument put into in the air. In that situation is indeed debatable whether there is a "correct" phase that must preserved to make the reproduced sound wave match the original sound.

    A guitar amp is totally different. In no way is the goal of a guitar amp to reproduce the original sound waves the electric guitar put into the air. We're interested in creating a totally new sound using the electric signal from the pickups as a starting point. Since we're not trying to reproduce anything there's no way for what we end up making to be "wrong".

    The phase of guitar pickups is 100% arbitrary. There's no standard and different makers wind them in different ways so you always have to check the phase yourself when putting pickups into a guitar that weren't made as a set.

    Who could make a case that any relative word like "up", "down", "east", "west" or any other direction should correspond to any particular electrical voltage anyways? Did Jimi have to reverse the pickup leads when he played the guitar upside down? :lol: Would upstrokes be "out of phase"? What about chicken picking or slap bass? Guitar pickups simply make an AC signal and we send that AC signal to the amp.

    And about that amp... This is not a flat response, constant phase sound reproducer. It too is a sound creator who's only goal is to make a pleasing sounding output waveform, which may or may not bear any resemblance to the input waveform.

    A positive going voltage at the input is no way expected to correspond to a positive going signal at the output. Count the inverting stages of some famous guitar amps and you'll find both even and odd numbers. And every bit of tone shaping from cathode bypass caps to coupling caps to tone stacks causes frequency dependent amounts of phase shift so even if one note did happen to come out of the amp roughly in phase with the input another note may not at all.

    I promise we're not a bunch of lunk heads who simply don't know all these smart things the hifi guys talk about. It's a different case where there simply isn't any kind of "correct" phase.
     
    Last edited: Aug 5, 2020
  4. tubegeek

    tubegeek Friend of Leo's

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    @elpico If we're not a bunch of lunk heads wtf am I even doing here?

    You make a compelling case. Lord knows we aren't sending snare samples through our guitar amps.

    I believe the convention is: when Bo Diddley drags his pick TOWARDS the headstock, that's supposed to be positive.
     
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  5. DougM

    DougM Friend of Leo's

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    Even in the world of hi-fi/audio, the signal is sent through so many different electrical devices, from microphones, to mixers, recorders, signal processors, mixdown from the original recording to master, and the machines that transfer the master recording to its final format, whether vinyl, CD, or hi-res files, there's absolutely no way to maintain absolute phase, or to even know which phase is true to the original waveform traveling through the air.
     
  6. soundchaser59

    soundchaser59 Tele-Afflicted

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    Reading the entire comment so that your response makes sense and answers the question matters, too. Your explanation is good, but that's not what he asked. (sorry, no offense, but one of my peeves is when people at work just read the first half sentence of an email and then hit reply, and they never answer what the email really says or really asks. that peeve spills over into forum threads)
     
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  7. Twang-ineer

    Twang-ineer Tele-Meister

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    Simple answers here....
    If you have only one speaker it does not matter in any material way. See the previous comments.

    If you have one speaker in a combo and you want to use an extension speaker cabinet with it (BTW now you have two or more speakers), you should check that all speakers are in phase. Do not trust even new- out of the box speakers to be correctly wired.

    Wire the speakers in series or parallel (your choice) apply the 9V battery to the speaker cable and make sure that they all move in the same direction.

    That means that they are in phase.
     
  8. Paul-T

    Paul-T Tele-Meister

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    This is an interesting issue.

    Absolute phase does matter in recording studios because of things like microphone pop, which is like a step change, almost pure DC. Air is pushed towards the listener, starting with a compression rather than a rarefaction. The same applies to other wind instruments. Some people (not me) can hear if it's reversed, ie the air is pulled. A snare might well be the same as before the head oscillates it effectively pushes air towards you. I believe listeners have detected the difference in tests. Hence most high-end studios are designed to control absolute phase.

    However, absolute phase simply cannot matter for guitars because, as pointed out, there is no defined phase for pickups and no equivalent to that microphone pop.
     
    Last edited: Aug 6, 2020
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  9. D'tar

    D'tar Friend of Leo's

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    What if we use a rotating speaker? Does it matter if it rotates on the x axis as compared to the y axis? How many gain stages does the circuit have? Is the guitar signal ultimately inverted anyway?

    These questions of course... do not... in any way.... need to be answered!!!

    Where is @Mfa88

    You ask these profound questions and skip town! LOL.

    Good discussion fellas, have a great day!!!
     
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  10. mrriggs

    mrriggs TDPRI Member

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    That is so funny you mentioned Hendrix playing an upside-down guitar.

    I was going to make the same comment but resisted because in would invariably lead to a discussion of how strings don't move side-to-side but spin around like a jump rope. It's the vertical distance of the string that the pickup is sensing, not the side to side motion, so it doesn't matter which way the string is spinning. Someone would reply, "Oh yeah, what if the string isn't centered over the pole?" That would turn into a whole different discussion of magnetic fields with number crunchers one one side and guys who tried X and totally heard a difference on the other side. And on and on....

    Aren't message boards great! Someone asks a simple question, it gets answered within the first few replies then the thread goes on for ten more pages with nothing but pedantic bickering. I certainly enjoy it and have found myself on both sides. I love super detailed technical analysis but also believe that at the end of the day, if it sounds good it's good, no matter what the numbers say.
     
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  11. tubegeek

    tubegeek Friend of Leo's

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    I'm afraid I'm not the only one with WAY too much time on his hands these days. Some of the threads lately - but in the past as well - have indeed gone way off into the weeds, it's true.

    The good news is that this topic allows for only two possible "standards" - for some issues, you have the latitude to just keep adding more of them!
     
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  12. screefer

    screefer Tele-Holic Silver Supporter

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    Speaking for myself and possibly other newbs/rookies, I find pearls of wisdom is these threads.
    ....guitar string moves like a jump rope and just the vertizontal distance gets recorded. Who knew?
    Now I have another piece of the puzzle to research!
    Thanks
     
  13. soundchaser59

    soundchaser59 Tele-Afflicted

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    You said it matters if there is just one speaker.

    He asked you why does it matter if there is only one speaker.

    You explained why it matters when there are two speakers.

    What did I miss?

    (I'll wait till later to address the fact that my response to you was obviously a thousand times more insulting and degrading than your response to me. my bad)
     
  14. D'tar

    D'tar Friend of Leo's

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    I am quite certain that he omitted the " n't " in his statement above. I'm not trying to speak for TW but hey it's all good.
     
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  15. Blue Bill

    Blue Bill Poster Extraordinaire

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    One method: Try it one way, then the other. Whichever sounds better is correct. If there's no difference, then it doesn't matter.
     
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  16. telemnemonics

    telemnemonics Telefied Ad Free Member

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    Hahahahahahaha arrived late and found this!!!!!

    Yeah so interesting discussion.
    My feeling on this; which BTW is VERY important: is that speaker polarity should be soldered up correctly, because, it's the correct way to solder wires.
    Any argument suggesting soldering correctly is incorrect, well dammit that argument is incorrect!

    I suppose that if we lived in a bubble and there were exactly >one< guitar amps left on earth, or in our little bubble, then it wouldn't matter, and we might as well stop bothering with soldering stuff correctly.

    But I mean how often do we live in a bubble?
    Maybe if there was an "event" and the whole world was in "lockdown"?
    But c'mon, that isn't going to happen any time soon.

    Damn though, that would be tough, just imagine being stuck at home with spouses and kids we don't actually like all that much?
    Could result in some hurt feelings 'n' s#!t!

    So wire up that speaker any way you please, don't bother with correct soldering, and if you ever leave the house again or have a guitar playing visitor, you can fix the mistake then!
    Why do today, what you can just as well put off 'til tomorrow?

    Years ago I had amps and speakers from before "the industry" standardized phase.
    Old Marshalls were built reverse phase to old Fender amps, while old Jensen speakers were marked on the frame incorrectly.
    An amp circuit might reverse the phase an even or odd number of times and really not be right or wrong in terms of phase.
    But a speaker really only has one correct phase wiring, so that's easy to decide on.

    As far as modern pro studio gear?
    Are some suggesting that in pro audio they haven't agreed on which way to wire up signal transfer?

    Plenty of times I've had amps out of phase and had to figure out which was WRONG and fix it.
    I generally went with choosing the speaker wiring as my standard of "correct", but now that I think on it I forget what I did when running BF Fenders with old Marshalls.

    Can anybody correct me in thinking that somehow the JTM45 circuit was OOP with the 5f6a Bassman?
    I think I must be misremembering that?
    Makes no sense since they were supposed to be identical circuits, unless the input was reverse phased which also males no sense what with grounding. I know for a fact that mid '60s Jensens were marked WRONG on the terminals, while same year Celestions were marked CORRECTLY.
    So if on the showroom floor a new BF Fender was OOP with a new JTM45, it had to be due only to the INCORRECTLY marked/ wired Jensen speakers.

    Glad all that got worked out before 1970 or so!
     
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  17. Mfa88

    Mfa88 TDPRI Member

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    Wow. That escalated quickly.

    Thanks for your replies. I only have one speaker :)
     
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  18. Tom Kamphuys

    Tom Kamphuys Tele-Holic

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    We might needs to switch the polarity of our feedback...
     
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  19. elpico

    elpico Tele-Afflicted

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    Okay, let's say you sit there in front of the amp flipping the leads around and twanging away on the high e string and you discover one way sounds like crap and the other puts the speaker perfectly in phase with the guitar so that high e now sings like an angel. Problem solved?

    Take a single step back. Your guitar is now fully out of phase with the amp and would need the speaker leads reversed to get that angelic sound back.

    Why? The wavelength of a 330hz sound in air is about 3.5 feet, which means the phase relationship between the guitar and the amp reverses every 20" you move away from the amp. Unless you're going to rig up some kind of guitar polarity switch in your shoe that keeps flipping the leads as you walk away there's just no way to keep your "preferred" phase relationship.

    And that's just one note. The distance that will flip the phase is different for every frequency so play a double stop and try to find a distance where neither are flipped and you could be walking a while...
     
  20. tubegeek

    tubegeek Friend of Leo's

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    ...mutter mutter mutter "phase" mutter mutter mutter "polarity" mutter mutter mutter....
     
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