Santa got me the Parts Express Omni-mic test kit this year. A few years ago, after reading many posts on this site and others and asking a few questions, I decided to update and modify my nearly 40 year old JBL L-88 novas. I installed new caps of the same value and put in real posts and got rid of the funk and weak spring type posts. No real difference in sound. After reading more I saw extensive posts by (Swerd and/or Ziltch) I decided to follow their lead on the modifications they did on L-100's. I did a search but cannot find these posts. I traded someone the original tweeters for some T-035ti's, Added a choke and plugged the ports. I also added more stuffing to the inside of the box. I think there was an improvement. The T-035ti's made the speakers too shrill compared to the old (025?) tweeters. I had left the L-pads and turned them down to a listenable level. In all I think they sounded better but didn't have a good way to measure it until now. I am attaching my print out of the results on the Omni-mic. I hope I am using it correctly. Any and all comments welcome. I just wish I had this test equipment before I did the modifications to see what the actual improvements were.
Graph 1 Sine wave of L-88 taken about 3 feet in front of center of speaker. Sine sweep
Graph 2 Sine wave both speakers driven taken front listening position about 10 feet away
Graph 3 Harmonic distortion
Graph 4 Bass decay
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