Have a capacitor built into them so that they don't receive any of the bassier sounds & blow. The JBL tweeters are a different set up. On the back of the JBL units it actually states that it is a MEDIUM TW (mid & tweeter) & to look at they are like a miniature coaxial speaker. These are fitted with an identical capacitor to the standard Harman tweeters, but this is fitted between the mid part & the tweeter to protect the tweeter dome. There is nothing fitted to protect the mid part. This is because these are supposed to receive their signal from the JBL amplifier which has built in low & high pass filters to prevent the bass being sent to the top of the dash where the tweeters are fitted.
Here are the JBL tweeters:
First thing I did was obliterate my broken standard Harman tweeter to get at the capacitor & find out what type it was. This isn't really something that can be undone as most of what I took apart won't go back together so it's just as well I'm using the broken ones to experiment with.
Once you've prised out the tweeters from the dash (no screws in there, they just pop out) you end up with this:
If you then grip the speaker at the back & twist it clockwise from the grill part, you end up with this:
If you do the same with the speaker that came out, you'll also find that this pops out of it's housing too leaving you with 3 pieces:
I then went to work with the small screwdriver. If you look at the back of the tweeter you see 2 little metal strips going into the rectangular box on the back (not the bit where the plug goes) & this is where the capacitor is. After a bit of stabbing & lifting:
I got the bugger out & here it is:
Unfortunately, this is the exact same as the capacitor that is fitted between the 2 parts of the JBL speaker. You could still use it, but then you find that you use both parts as the tweeter dome & this isn't what I wanted to do (although I will be using it on the blown one to practise my soldering & check that it all works). After trying to work out what rating capacitor I needed using an online calculator I came to the conclusion that I'm not an electronics whizz, I don't know what ohm rating these speakers are & that it would be easier to cheat.
I went in to the shed & found an old set of Sony 6x9 3 way speakers & had a look-see underneath the mid part of that. Result - a 6uf capacitor. That gave me the figure I (hopefully) need. Closest I can find to that are these 6.8uf on Ebay:
http://cgi.ebay.co.uk/MKT-Plastic-Foil- ... 5882a24ef4
& if you look at the pic below you'll see 2 pieces of metal which were attached by a wire - this is where I plan to fit the 6.8uf capacitor:
