Need Help with 2405 D16R2405 Polarity Please

[Zonker92]

Unlike the diaphragms I’m replacing, the new OEM diaphragms have no evident polarity marking. Each lead has a small black band on it, but that just seems to be from manufacturing. Battery testing doesn’t move the diaphragm sufficiently to determine whether it’s going inward or outward.

I do see inside the voice coil that one lead is different from the other (it wraps around), but that doesn’t tell me which is which.

Is there some clue I’m missing swing, like maybe the number stamp location?

Is it sufficient if I just make sure both diaphragms are in phase? Since I can see where one of the leads wraps around, I guess I could just do that.

Speakers are L300s; tweeters are 077s.

Thanks.

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[Zonker92]

Here are the marks I mentioned above, and the differences inside the voice coil (one lead that seems to wrap around, and one that doesn't).

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[Zonker92]

Ok, I just realized that on both the old diaphragms (one gold, one blue), the wraparound lead corresponds to a black dot on the front. I’ll mark the new ones the same way. That’s the negative lead, right? Thanks.

[toddalin]

It would seem to me that when you insert the dowel locating pin, the leads are going to end up in the correct direction.

[Zonker92]

That wound up being true, although I didn't think of it at the time. Plus, I just wasn't sure the diaphragms were all made with the same orientation vis-a-vis the pin holes, but sure enough ...