I'm working on a project that will update an old console based JBL system (this was probably not factory JBL but custom). It currently contains a D131 and 075 with a first order JBL xover. I've been informed that the xover is probably set for 2500hz. Coil and cap are unmarked so I cannot confirm this. The problem with the system right now is that the 075 produces a very eratic response and the midrange clarity is poor.I plan to replace the 075 with a new modern compression driver (Radian 475) matched with a DDS waveguide. The combination has a usable frequency response of 800-20K, but requires a 4th order xover at 800 hz. I do want to cross as low as possible since I believe that will improve MR clarity.
Based on the factory spec of the D131 (I do not have the drivers available for test right now) and the cabinet dimensions (2.52 cubic feet) the D131 will develop a very peaked response at resonance with a standard LR 4th order LP (according to Unibox). It seems in part that this is due to the size of the enclosure.
I'd appreicate any suggestions for successfully integrating the two drivers. Also, I suppose, this begs the question why not use a Pi alignment. I admit that I'm not sure the tradeoff of the higher xover frequency would be beneficial in this case. Again, advice/comments appreciated.
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