Newbie question on driver polarity

[jacket_fan]

I am working on my first speaker project. I did a search, but did not find an answer to a real basic question. So forgive my newbie dumb question. But you gotta start somewhere.

When I hook up the drivers to the crossover, how do I know I have the polarity correct? I got a kit from Mediasound, the Zaph 5.2s, and the speakers do not have any markings. Is it something that you can tell "by ear" or something even more obvious?

[Kevin P]

There's no red mark on one of the terminals? You can use this pic as a reference.



Does either driver have a polarity mark? If one does and the other doesn't, hook up the marked driver correctly, then try the unmarked one both ways and listen to find out which way sounds correct. The speaker will sound "weird" (like a hole in the sound between the drivers, and a null in the frequency response) if one is connected the wrong way.

[Undefinition]

Use a AAA battery across the terminals (you may need a bit of speaker wire for this). The + end of the battery connected to the + terminal of the speaker will make the cone/dome push outward. The + of the battery to the - terminal will make the cone/dome push inward.

[jacket_fan]

Thanks gentlemen.

I could not see any marking on the tweeter. I could have missed it. I will look on the terminals again tonight on both drivers for a red mark. The one distinguishing thing on the woofer is that the terminals are different size. One is narrower than the other.

Also, how do you tell which way the tweeter moves?

[stuofsci02]

You will not be able to see the tweeter move...

[Undefinition]

You will not be able to see the tweeter move...

Obviously, you've never tried it.

[Biff]

In my experience, the larger terminal is always +, and while I am almost positive about that, if anyone has negative comments they can consider themselves terminated.

[1Michael]

Never, ever, ever, rely on the manufactures markings. Always use the battery test or we will be saying "told you so".

[JonP]

Yep... occasionally the manufacturer gets it wrong, too. Rare, but you hear about it happening. When you see it move, you'll KNOW the polarity.

And yes, look close and you will see a tweeter move as well.

[jacket_fan]

I did find polarity markings on the woofer and Biff is correct that the + is on the larger of the two terminals.

Thanks for the tip on the battery test.

[jacket_fan]

I finally finished the raw cabinets and fired the speakers up last night. And either I was lucky and connected the speakers up correct the first time or it does not matter. I tried the battery test but could not detect movement in the tweeter. What moves in the tweeter?

I used a test disk and tested for phase. So I know that I at least have them hooked up in phase.

I will follow up on the original question, what should I hear if I had one of the tweeters hooked up wrong? Or both wrong for that matter?

(As I typed this up, I realized what I should do is switch inputs to one of the tweeters and listen and answer my own question) ops:

[jacket_fan]

Seriously, what part of the tweeter moves that you can see. I did the battery test, and it is clear which way the driver moves on the woofer, but I cannot tell on the tweeter.

[Undefinition]

If the tweeter is hooked up to its filter, you won't see it move (the crossover won't let DC make it to the tweeter). However, if you hook a battery up to the raw tweeter's terminals, you will see it move. It's pretty subtle, and it helps to look at it from an angle. I've done it with the DQ25, so I know it works.

[jacket_fan]

When I hooked up the battery, I could hear it, but did not see movement. I assume the dome is what moves?

[jacket_fan]

To follow up. I redid the battery test with better light. And yes, the dome does move. Interesting what good lighting will do. I also did an experiment where I changed the polarity of the tweeter in one of the speakers. Pretty confident now that everything is wired correctly.

This was a fun project for a first time speaker build. (That is if I don't count the subwoofers) Good experience, and learned some things about contact cement. Finally got to a process of putting down 2 coats of the thin contact cement, then a coat of the gel, and it worked quite well. Prior, using only the thin stuff, I never did get much tack. The three coat method stuck quite well. Still have to decide on exactly what finish. Whether to go natural, or dye and stain dark.

This experience may lead to another try, with perhaps a more unconventional box shape.

[Paul Spencer]

Mark, two issues here. First is that with each individual speaker, the polarity between tweeter and mid is correct. Sometimes the tweeter needs reversing. If it's the wrong way, it's easy to see the dip at the crossover in a response plot and these days it's easy to get hold of a low cost measurement setup.

Second is each speaker relative to the other. If everything is right, but just one tweeter or mid is wrong, then the effect is limited to part of the sound. Either way, if polarity is wrong, something will not sound quite right. The most obvious sign is weird imaging. If the whole speaker is reversed, then you notice it most when dead centre. I remember some old Bose speakers at uni set up that way, no one seemed to notice. I'd walk past and immediately notice that weird sound that is hard to describe but easy to pick. It's a vague coming from nowhere sound.

One suggestion. Once you have it sorted, make it easy for yourself with the cables somehow. A lot of annoying cheap cables are hard to pick polarity unless you have bright light.