My First Speaker Resurection, Driver Replacement Question

[Andrew Heck]

Howdy, so I picked up a pair of AR M4.5s today for $30. I Ohmed everything out and I at least have continuity through the voice coils and resisters (don't know if that's necessarily a clean bill of health, but at least it's a thing). Problem is that one of the mids (1210131-2) has a busted dust cover and i suppose I need a replacement driver, so let's do the pair while we're at it, right? Twoish questions:
A) I disconnected the driver and she reads 5.2 Ohms, and when looking for replacements at Parts-Express, there were only 4 and 8 ohm varients. Does my reading actually correlate to the specs I'm looking for?
B) What other specs should I arm myself with in my search? Cross-over frequency? Max watts? Obviously size, etc. etc.
C) Where would you start to look?
Okay, that was three. Anyway, any advice is helpful so thanks in advance.

 

[Watthour]

Is it the VC dust cover that is damaged, or a rear cover? If it is a frontal VC dust cap, it can be replaced fairly easily. Those are available in any number f places, such as this:

https://www.simplyspeakers.com/speaker-dust-cap-mesh-screen-dc-3s.html

 

[darkhosis]

This may be a better thread suited to the Speaker forum.

When you connect your multimeter to the speaker, it's measuring resistance not impedance. So 5.2 ohms resistance is within normal parameters for an 8 ohm rated speaker. it's a common mistake.

Really confirm the driver is toast. If you're referring to the 8" midrange speaker, it passed the first test. The speaker leads are good.

Next, look and listen for signs of voice coil separation. Tap lightly but firm around the cone and listen for odd noises. Look where the spider (the accordion thing) meets the cone and check if it's raised or unusual. Lastly, and be cautious if you're not used to doing this, hold the frame and use your thumbs to put even pressure on the cone and press down. Not too far, you're just listening for rubbing or scraping sounds. Compare with the other mid, look for differences.

I agree with Watthour, you're really hoping to replace the dust cap. Finding a replacement driver can be tricky and it kills the value of the speaker. If you want help with the evaluation, post some pics. Good luck!

 

[redk9258]

If you do need to replace the driver, I would hunt another OEM one down. I would not use an aftermarket driver.

 

[Powertech]

Have you tried listening to them?

 

[mhardy6647]

Is there an audible problem with the driver, or is it just the dust cap?
If the latter, don't sweat it; the problem's fundamentally cosmetic -- or replace the dust cap if it bothers you.