Ok folks, I'm gonna chime in here with a technical request. When I was in high school, I purchased an old pair of JBL monitors (circa 1985-86) with one blown tweeter. At the time, they were a good deal so I installed some piezo horns from Radio Shack in both units for timbre matching. Recently, thanks to har, I became a new owner of some Polk LSi (Vifa) ring tweeters from Ebay. I'm looking at pulling out the piezo horns and installing the ring tweeters, but am a bit concerned about the existing x-over that's in the system and how adding a 4 ohm tweeter to a "speaker marketed as a 8 ohm speaker" would affect the performance of the Vifa. Attached below is a picture of the X-Over, and the post below this will be the tech specs on the speaker that JBL customer service provided me with.
I need help on the following items:
- if I install the 4 ohm tweeter in place of the orginal 8 ohm tweeter (the original woofer and midrange are rated for 4 ohms), would I now have a speaker enclosure rated for 4 ohms?
- i know caps and inductors used to select the x-over frequency are selected based off of speaker load. What changes would I have to make to the orginal x-over to keep my high-pass frequency at 3.4 KHz.
- looks like the mid-range driver is swapped phase. I though 1st order x-overs weren't supposed to have this?
- anyone here have a circuits program and could build this x-over to confirm if the phase shift will change from the orginal design and what the new nominal speaker load would be?
From the attached x-over network, it looks like JBL used 3 seperate 1st order crossovers for their network, with the mid-range having both a high pass and low pass filter to keep it in the range of 1.1 - 3.4 kHz.
Thanks for any advice guys.