J's & H's and Compression Drivers & More
A few random questions.
I am trying to gather drivers together for a speaker project. It will probably use two woofers per side. The one woofer I have is an "H" - 8 ohm - and there is also a "J" version - 16 ohm. I'd rather have all J's but it seems to rather a rare woofer - at least they're rare on Ebay - and I may not be able to find all of one version. But maybe I can find two of each. Anyone mix H and J versions together? One H and one J in each speaker. I don't expect this is a problem, so long as the amplifier is stable in the load, but maybe I'm missing something.
I'm new to horns. They're a bit of a mystery to me, but I'm picking up bits and pieces. The horn I'll probably use is the JBL 2382A, but what compression driver is best? I know the 2450 and 2446 series will work, and I'll likely find the 2446 cheaper. How about the more common 2445 series? What is better about the 2446 over the 2445? I know there are some older drivers that will fit, according to the spec sheet, but I'm a bit leery about them.
Several places have mentioned horn equalization. Does anyone use it, how do you do it, and how will I know what the correct equalization is? Is this a subjective thing or is there a standard for each horn?
Thanks!
My measured specs on a pair of 2220B's!
Quote:
Originally Posted by
speakerdave
Possibly the 2220C was a JBL Pro counterpart for the 130B, a "32 ohm" job that may have been hatched in the same flex-ohm strategy that was the source of many JBL 16 ohm drivers. The 130B crop up only occasionally on ebay and go for high prices. (Or maybe JBL feels no one really needs a 32 ohm driver any more.) I have some 2220B's on hand. The DCR shows they are truly 16 ohm drivers.
David
Revc 8 ohms - - - 8.1 ohms
fs 40.8 hz - - - - 41 hz
Qes .44 - - - -- - .34
Qms 2.55 - - - -- 2.37
Qts .377 - - -- -- .3
Zmax 54.7 ohms - - -63 ohms
Le .87 mh- - -- - .94 mh
Vas 9 cu ft -- - - -8.89 cu ft
BL 18 - - - - - -- -20.6
Sens 97.8 db- - - - 98.8 db
Eff 3.8 %- -- - - - 4.8 %
RMS 7 ohms - - - -7.7 ohms (mechanical)
Results taken from WT2 in my living room with less than ideal conditions.
The cones were not perfect and show signs of light abuse(dented cone indentations like a slipped screwdriver), but no major damage. These units are borrowed and I might keep them for the long haul for my 100 hz straight horn (Dr Bruce Edgar built).
I'm not sure the impedance of "my" units can be thought of as 16 ohm drivers. The impedance dances closer to 10 ohms for much of the testing I did.
Just thought I would share my results with you all!
Regards, Ron