For the sake of discussion, here's my two factory rehabbed 2435's just taken on PT-F1010 waveguides (PT-H being similar in earlier measurements,) with expanded vertical scale, 2.5 dB per dotted line, on AM crossover, which provides about 4 dB less "boost" than is used with 2426 in 4430, IIRC.
I'd have no qualms about tweaking the filter or EQ'ing 2.5 dB to make them more perfectly flat, though I'd consider the exercise "academic." They sound fine as is.
Also, Steve, your eBay 2435's could go back to JBL for confirmation of performance to spec. Both of mine needed gap cleaning and ferrofluid recharge; I understand yours are from the same source.
We also have the semantic issue of "boost." I'm not boosting anything here in the sense of adding HF drive as an active EQ would do. These filters reduce power selectively at the lower frequencies to flatten the response. It's semantic in that there's still a differential in the amount of power the driver receives at various frequencies, with HF getting the most, hence, "boost."
Supposedly, these drivers move mass breakpoint further into the HF region than earlier designs, reducing the magnitude of that differential. Indeed, they seem to require less total compensation, as noted above.
I suppose it boils down to an argument favoring beamy exponential horns. Having to equalize compression driver power response is inherent in using them above mass breakpoint. Doing it electrically versus acoustically is the question. Otherwise, use a tweeter, and buy all of THOSE compromises.
'Course, there's those who contend that compression drivers, themselves, constant directivity, and 4430's all SUCK hugely, in which case there's not a lot on the table here for discussion.
[We will persevere....]
because there are a lot of ferrofluid tweeters on the market that don't have any problems with HF extension.
Originally Posted by stevem
