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Correct polarity for Large Advents?

jay

jay

Active Member
Hi lads,

I just came form the AA site where I found an old thread that suggested that I may not have my speakers correctly wired.

If you're familiar with large Advents then you know that there have no traditional + or - speaker posts on the back but rather two posts, one marked "8" and one marked "0".

Question is, Which one is positive and which is negative?

Is there a way to test for correct polarity by some kind of performance test?

Thanks, Jay:cool:
 
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Yeah, that's a bit of a puzzle with the old Advent Loudspeaker!
Mine still have the sheets attached to the backs of the cabinets, and their instructions are to hook 'em up and face 'em together and listen. If the bass (and they've got healthy bass) isn't what it seems it should be, reverse one of the connections.
I've found that spades make connecting them easier. On the bigger Advent Loudspeakers that I have I use o-ring connecters. That pair of speaker wire is special just for the Advents.

I could never get bare wire to stay. Mebbe if I would've used something smaller than 12-ga. ...

pete
 
I think the "0" is negative and 8 positive (8 for 8 ohms)

If I recall correctly, headphones have three connectors one for positive left, one for positive right and the share the negative.

Does that sound logical ? :dunno:

Chris
 
Thanks Pete, Chris;

Mine also still have the sheet on the back and (ahem) I really didn't want to admit that when doing the face-to-face test, I can't hear any difference in the bass response!

I'm getting up there (38) but didn't think I was that deaf yet!:o

Jay
 
You could do the old battery test. Meaning take a 1.5 volt battery, connect a length of speaker wire to the speaker terminals. Take the wire coming off the speaker terminal marked '8' and hold it to the plus or postive terminal of the battery. Take other wire and just tap it against the negative terminal of the battery. If the cone moves outward when you do this then '8' is your positive terminal. If it moves inward then it's your negative terminal.

If this does not make sense, just make sure that when you wire up your system that you keep the speakers in phase with each other. e.g., if '8' is connected to (+) on your left channel make sure you do the same for the right channel.
 
Gracias Dj

That's the first clear explanation of the old battery test that I've ever come across.
 
Someone once asked on RAT (rec audio tubes) if there was something he could buy at Radio Shack to test the polarity of his speakers. Great font of wisdom that I am I say sure, but they will still want your phone number when you buy that AA battery! Course then I told him how to do it. A word of warning, you can do this to speaker systems and woofers but try it on a tweeter by itself at your peril. I found that out all by myself.
 
As long as you wire both speakers alike, there is no correct polarity. They will sound the same either way.

Before we start an argument... everybody that has spent hundreds of hours in a sound lab, staring at O-scopes, playing with sythesizers, filters, etc, learning the sound of different wave forms, shifting phase of overtones around, etc... raise your right hand.

Just as I thought.

Well, I have.

I am telling you, you can hear phase of overtones while they are actually being shifted, but once stable, there is no difference in sound. A sawtooth wave with a vertical climb and a gradual fall sounds exactly like a sawtooth wave with a gradual climb and a vertical fall (180 out of phase, aka reverse polarity). The ear cannot tell absolute phase. It can tell when phase is moving.

Anyone who says they can reverse the polarity on both speakers and tell which is which is pulling your leg. He is trying to BS you about his "golden ears".

Do you need to know polarity of speakers? Well, it depends on what you mean by speaker... a speaker system or an individual driver. With certain crossover networks (12 db/oct) the tweeter in a 2-way or the midrange driver in a 3-way needs to be opposite polarity from the adjoining drivers. This is because of a 180 degree out of phase condition at the crossover points which results in a null at that frequency... that is unless one of the drivers is "crosswired"... which results in a flat response at the crossover point. The fact that the rest of the frequencies produced by that driver are now 180 out of phase does not matter. It is inaudible. Take that to the bank.

But in the case of your speakers, terminals are marked 0 or 8. As long as both + wires from the amp's speaker terminals both go to the "0" terminals OR both + wires go to the "8" terminals, all will be OK. It does not matter which is plus or minus. Just that the Left and Right speaker both be in phase.
 
I think Paul is right on the money here. To extend the arguement, setting up your system with "absolute phase" is assuming that every step of the recording process also faithfully reproduced absolute phase. I've been in more than one studio where a patch cord was out of phase. No one ever got out the continuity tester to figure out which one was wrong, they just started swapping. (we monitor everything in mono at some point when mixing for TV, so one channel out of phase is very obvious)

Take care,

Ed
 
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