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quindecima
11-18-2015, 03:49 PM
I am looking at some nice tweeters for my 4345 clones that I am building but they are 16 ohm and I need 8 ohm. Does it make a great deal of difference? I had heard it does not but can't remember the source. The rest of my drivers are 8ohms.

grumpy
11-18-2015, 06:45 PM
Depends on what you call a great deal of difference.
Substituting a 16 ohm driver where an 8 ohm driver
is called for will throw off -passive- crossover points
and driver eq.

Perhaps fortunately, the 4345 was designed for a 2421B

http://www.jblpro.com/pub/obsolete/4345.pdf

quindecima
11-18-2015, 07:05 PM
Would it be possible to compensate for the 16 to 8 ohm difference with resistors in series with the + and - terminals of the driver, or should I just forget it and keep my eyes open for the 8 ohm pair I need?

grumpy
11-18-2015, 07:20 PM
Why do you need 8 ohm? Perhaps I'm missing something...

quindecima
11-18-2015, 07:43 PM
I'm looking at the 4345 specs and it indicates the impedence as 8 ohms so I am assuming (wrongly?) I need to be picking up 8 ohm speakers.

grumpy
11-18-2015, 07:52 PM
See the pdf I posted above. :)

quindecima
11-18-2015, 08:00 PM
O.K. I read it thru three times, what am I looking for? The 2245H, 2121 or 2122 or 2123H, 2405H are all 8 ohm Nowhere can I find a spec for the 2421B.

O.K. I finally found it, the A model is 8 ohms ad the B is 16 ohms, darn what an ordeal. That little foray probably saved me mucho headaches. So I am good to go, I had visions of a stack of speakers all the wrong impedance.

grumpy
11-18-2015, 08:27 PM
Yep. Post #2. That's why I didn't follow.

grumpy
11-18-2015, 08:38 PM
Sorry for the detour. If I had just answered your original question, you'd be looking for the wrong driver.

http://www.jblpro.com/pub/obsolete/2421ab.pdf

quindecima
11-18-2015, 08:43 PM
That's fine, it's things like that that will stick in your mind and benefit you in the long run.