How do you tell which side is positive penta tweeter?

Hi Guys,

How do you tell which side is positive and which is negative on a penta tweeter? They don't appear to be marked in any way.

Lee

Hi Lee,

that's an interesting question. I opened the front to have a closer look at it. 

The result is: the tweeter fits only in one direction. The round side has the pink cable and the other goes with the white. I suggest, the pink is the positive, but I'm not sure.

Chris

Yes that appears to be the case :-) thanks.

I've got another issue though. One speaker sounds different to the other when I play pink noise through them, one is brighter than the other. I've recapped the speakers and tested all my solder connections and they are all fine. I just measured the impedance of the tweeters and one measure 4.4 and the other 5.1.... Any thoughts?

Lee

The impedance is one aspect - or roughly the resistance. But the speakers coil can be mechanically damaged as well or got too hot. But it's difficult to prove the movability of the membrane. For a hearing test, a plain sinus sound is really good to find defects. Days ago, I found a really useful smartphone-app Audio Fun Generator. Give a frequency of 5 to 10 kHz to the speaker and try to figure out. The best way is a sweep. I think, you know, how a sinus should sound like. And while playing, move your finger around the dome gently. The sound should not change to a hiss or something like that, that indicates a scratching of the windings of the coil. Really hard to describe!

Chris 

Hi Chris,

Just done the sine wave test and they both sound clear up past 18khz where my hearing cuts off.

Moving my finger gently over the domes didn't alter the sound at all and they both remained clear.

I've started a new thread for this issue.

Lee

Hi Chris,

Could you please do me a massive favour and measure the resistance across your tweeters please.

I have one at 4.5 and one at 5.1. I've just been in touch with a seller on eBay and his measure 7.2!!

I'm confused

Lee

Hi Lee,

to my surprise, the original label on the tweeters say 8 Ohms, so your dealer comes closer to that. My tweeters have 5.87 and 6.1 ohms. I have a calibrated FLUKE 79 multimeter, so I can guarantee for a good reading. I think you shouldn't pay so much attention to the resistance. Do you have a circuit diagram? Because the midrange speakers are wired in a special way.

Chris