speaker connections

[LITTLEWING]

Just a quickie, I took the amp section out of my Squier 15w combo to make a 12" praccy combo and in between weekends of messing about I've forgotten which way the speaker wires go. There's one black and one white but I can't remember which is positive and negative. I'm assuming black is neg but things are never simple in 'ampworld'. Anyone have an idea?

[Musky]

For a single speaker it makes no difference. You only have to watch the polarity when you're wiring up multiples.

[BILL POSTERS]

If the polarity is wrong you will lose some bass response.

If you have a multimeter, measure the resistance to chassis (or to the outer of one of the jack sockets) of each wire on the lowest ohms range, the lowest is the negative. Most likely black though, as you said.

If your not sure which is which on the speaker, connect a 1.5v battery across it, the right way is when the cone moves outwards.

[icastle]

Wiring the speaker backwards will have a detrimental effect.

White or Red are generally +.

[bremen]

Musky is right. Bill and Ian are maybe assuming there's more than one speaker in your rig.

[BILL POSTERS]

[quote name='bremen' timestamp='1367783058' post='2069455']
Musky is right. Bill and Ian are maybe assuming there's more than one speaker in your rig.
[/quote]

Nope, just quoting what I was taught in college about a hundred years ago studying for my G&G.

[bremen]

If its a single speaker in a combo there really will be no difference connecting it one way or the other.

[BILL POSTERS]

[quote name='bremen' timestamp='1367798732' post='2069658']
If its a single speaker in a combo there really will be no difference connecting it one way or the other.
[/quote]

If you say so.

Cant say I ever bothered to try it.

[mcnach]

[quote name='BILL POSTERS' timestamp='1367833249' post='2069855']
If you say so.

Cant say I ever bothered to try it.
[/quote]

bremen is right.

think about it: polarity just dictates when the speaker is moving forward or backwards.
It's only when you have multiple speakers that it can be an issue when you have one moving forward and another backwards, resulting in some cancellations.

It's important for wiring the speakers in your stereo.

It does not matter whatsoever in a single speaker combo.

[BILL POSTERS]

I was taught it was important, this was back in the late 60s, first year of a 5 years Radio & electronics engineering course. Most things were mono back then, with single speakers. A quick look on google confirms what I thought. But y'know - lifes too short to lose sleep over it.

Edited May 6, 2013 by BILL POSTERS

[mcnach]

A quick look in google can confirm the Earth is flat if you look for it

Seriously, don't take my word or anybody's word for it. I don't know a whole lot about electronics or speakers... but I do know about what changing the polarity on a speaker does and why. It's simple, I am sure you can find a simple explanation too (I can't be bothered to google it for you, sorry). It makes no difference in a single speaker system. If they taught you it mattered, I suspect that either you misunderstood, or that there is something missing in the context.

In our case: combo with a single speaker: it doesn't matter one bit how you wire it.

For those who remain unconvinced and can't be bothered to figure out why, just try it.

Edited May 6, 2013 by mcnach

[Dad3353]

It could [i]become [/i]important in a mono system if, later on, one added an extension cab (combos quite often have this option....). It's just a matter of convention, otherwise (early JBLs used the opposite cone movement convention, and can be a trap for the unwary...).
For a home practice amp, no real matter, but I'd take the white to be the 'hot', or positive wire just the same.

[LITTLEWING]

Thanks for all the replies chaps. I've wired the speaker up as white for positive anyhoo and everything sounds nice and punchy. Cheers again guys.

[mcnach]

[quote name='Dad3353' timestamp='1367862980' post='2070385']
It could [i]become [/i]important in a mono system if, later on, one added an extension cab (combos quite often have this option....). It's just a matter of convention, otherwise (early JBLs used the opposite cone movement convention, and can be a trap for the unwary...).
For a home practice amp, no real matter, but I'd take the white to be the 'hot', or positive wire just the same.
[/quote]

Absolutely. That's why I was making the point about missing the "context" earlier, when I replied to BP.

[BILL POSTERS]

[quote name='mcnach' timestamp='1367868016' post='2070474']

Absolutely. That's why I was making the point about missing the "context" earlier, when I replied to BP.
[/quote]

tbh, thats a bit offensive. I didnt misunderstand, nor miss the context. It was even demonstrated.
For some reason that particular lecture stuck in my mind while most of the course was forgotten years ago.

[mcnach]

[quote name='BILL POSTERS' timestamp='1367913250' post='2070806']
tbh, thats a bit offensive. I didnt misunderstand, nor miss the context. It was even demonstrated.
For some reason that particular lecture stuck in my mind while most of the course was forgotten years ago.
[/quote]

I'm sorry, I did not mean to sound offensive at all. By context I meant that although polarity matters [u]not one single bit for a single speaker by itself[/u], it may be important to take into account *[b]if[/b]* it's likely to be used as a part of a multiple speaker system. That's the kind of context I meant, the context in which a speaker was going to be used.

A practice combo is not typically used with an extension cab, and the OP's amp is not fitted with an extension speaker connector unless he added one himself. If he added one himself, then as long as he used the same polarity it does not matter which way around he wires the speakers.

A single speaker does not care about the polarity. If you saw it "demonstrated" then it would be more useful if you explain to us how it was demonstrated, because its rather odd...
I really don't mean to offend you But what you were saying was incorrect (at least in the way you said it, that's why "context" may be relevant). Please don't take it personally. Just trying to correct misinformation, that's all, without making personal judgement calls.

[BILL POSTERS]

[quote name='mcnach' timestamp='1367916914' post='2070844']
I'm sorry, I did not mean to sound offensive at all. By context I meant that although polarity matters [u]not one single bit for a single speaker by itself[/u], it may be important to take into account *[b]if[/b]* it's likely to be used as a part of a multiple speaker system. That's the kind of context I meant, the context in which a speaker was going to be used.

A practice combo is not typically used with an extension cab, and the OP's amp is not fitted with an extension speaker connector unless he added one himself. If he added one himself, then as long as he used the same polarity it does not matter which way around he wires the speakers.

A single speaker does not care about the polarity. If you saw it "demonstrated" then it would be more useful if you explain to us how it was demonstrated, because its rather odd...
I really don't mean to offend you But what you were saying was incorrect (at least in the way you said it, that's why "context" may be relevant). Please don't take it personally. Just trying to correct misinformation, that's all, without making personal judgement calls.
[/quote]

OK, no worries.

Funny how this has stuck in my mind, I would have only been 16 at the time. an apprentice on the RTEB/City and Guilds 48 or 224 course. most of which if forgot as soon as started to actually do the job.

Demo was pretty simple really, it was after all one of the first lectures. Started out with a speaker, audio osc, turntable, amp etc. demonstrated the upper frequency limit of hearing. played a test record. had a switch which reversed the speaker - yeah, I know, not a great idea, but this was 1969 - there was a definite difference, although you probably wouldnt notice it if you had to wait while the speaker was disconnected and re connected.

And no, it was not stereo, Stereo demo came later.

[Beer of the Bass]

I have a double bass preamp with a phase reverse switch, which should have exactly the same effect as reversing a single speaker. I found that flipping the switch in between playing notes makes no audible difference at all, but if the phase is switched mid-note the transition itself is noticeable. Could this be what you heard in the demonstration?

[BILL POSTERS]

Very likely.

It was a long time ago, I cant remember the theory behind why it makes a difference, and as I said, its not worth arguing or losing sleep over it. Just always done it the right way myself without questioning it.

An open backed combo certainly sounds different from the back though, which is the same principle.

[LawrenceH]

If you think about it, speaker polarity reversal in the context of the bass guitar/pickup stringed instrument is more or less equivalent to either changing the magnet poarity in the pickups, or plucking the string identically but in the other direction (up-down as opposed to down-up).

[Dad3353]

[quote name='LawrenceH' timestamp='1367928130' post='2071071']
If you think about it, speaker polarity reversal in the context of the bass guitar/pickup stringed instrument is more or less equivalent to either changing the magnet poarity in the pickups, or plucking the string identically but in the other direction (up-down as opposed to down-up).[/quote]

...which, to me, is as good a reason as any to not think about it..!

[bremen]

[quote name='BILL POSTERS' timestamp='1367928092' post='2071069']
Very likely.

It was a long time ago, I cant remember the theory behind why it makes a difference, and as I said, its not worth arguing or losing sleep over it. Just always done it the right way myself without questioning it.

An open backed combo certainly sounds different from the back though, which is the same principle.
[/quote]

That'll because you're also hearing the contribution of the voice coil cap from the front, which is where the high end comes from.

[BILL POSTERS]

[quote name='bremen' timestamp='1367929532' post='2071089']
That'll because you're also hearing the contribution of the voice coil cap from the front, which is where the high end comes from.
[/quote]

More likely the shape of the cone I'd have thought. Effectively a differnt shape from the front ?

[BILL POSTERS]

[quote name='LawrenceH' timestamp='1367928130' post='2071071']
If you think about it, speaker polarity reversal in the context of the bass guitar/pickup stringed instrument is more or less equivalent to either changing the magnet poarity in the pickups, or plucking the string identically but in the other direction (up-down as opposed to down-up).
[/quote]

If it was that simple, the cone would [i]exactly[/i] follow the string, which it doesnt. and all basses and all amps would sound the same.

[dincz]

If you consider how many inversions of polarity a signal goes through in the electronics between studio microphone and consumer speakers, the polarity obviously makes no difference whatsoever.

EDIT: Or the equivalent effect of moving your ears half a wavelength closer to, or further from a speaker.

Edited May 7, 2013 by dincz