Question on 2402H-05 Driver

[coherent_guy]

Hi People, I'm new to the forum, a long time JBL fan. A while back on the JBL Pro site, from the E-tent sale list, I purchased a pair of what are labeled 2402H-05 HF drivers. From what little info I could get from the JBL Techs, these were a special run of 2402's that have the diaphragms of 2405's, hence the 05 designation. My question is what is the appropriate minimum crossover frequency for this combination of driver and diaphragm. The 2402 is normally crossed at a minimum of 2.5 kHz, while the 2405 is spec'd at 7 or 8 kHz minimum. The driver itself is definetly the 2402/075 "bullet" tweeter. I did run them with a 3 kHz crossover at low levels for a short time, and they survived, but I am wondering what is the limiting factor concerning the crossover frequency, the horn geometry or the diaphragm. Is it safe to use the impedance curve of the 2405 driver in choosing capacitor values for passive crossovers? Thanks much for any help, I'm sorry if this topic was already addressed.

[scott fitlin]

Yeah, thats an old trick, you get a little bit finer sound with the 05 diaphragm. Even though JBL rates the lowest frequency as 2.5KHZ, I would never cross them over that low! With the 2402, 7K on an 18db slope is good, and with the 2405, 8K to 9K, is good!

I would imagine crossed over at 2.5kHz they sounded rough?

I run bullet tweeters in my system, and 7K is my crossover point!

[coherent_guy]

Thanks ScottyJ, your info was new to me. Some observations: Don't some of the old classic JBL speakers use 075's in two way configurations, with 12" and 15" woofers? For instance, the C45 Metregon, in version 230, uses two D130 woofers and two 075's with the N2400 crossover. Crossing woofers of that size that high seems crazy to me, but they must of run the 075's at 2.5 or 3kHz and up. I also believe I saw that the 2404 driver is spec'd to use the same diaphragm as the 2405, and is rated down to 3kHz. My initial concern was to not destroy the diaphragm by running it too low in frequency. I must say I did not think it sounded rough as you mention. I certainly agree the frequency response graph looks pretty poor at the low end of its range and the drivers use may not be optimal in that area, but it seems it was used that way.

[Zilch]

D130 is not a woofer, rather, an "Extended range loudspeaker." ;)

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