LSi15 modifications

dcgl22

I have a pair of LSi15's that I'm generally pleased with but would like to try a few (reversible) mods/tweaks to see if I can improve performance. Specifically, I'd like to bi-amp the speakers but not using the stock crossover frequencies/driver-combinations. If you remove the binding post jumpers from the stock LSi15 you have the abilty to separately power the tweeter from the rest of the drivers (two, 5 1/4" and the one 8" LF driver). To me, this does not seem the most advantageous spectrum to separate for bi-amping. I would prefer to power the combination of the tweeter and the 5 1/4 inchers separately from the 8" LF. I want to experiment with a tube amp driving the mid/highs and a powerful solid stage amp driving the 8" LF below 150 Hz. To begin my quest I have pulled out the binding post/crossover assembly and combined the two inputs to the crossover to one set of binding posts. Now I want to remove the wires from the 8" speaker terminals and insulate the push-on terminals on the wire coming from the crossover so they cannot short while disconneted. Now, with new wiring I plan to connect the 8" driver directly to the now unused other pair of binding posts. I will use either an outboard electronic crossover or passive components to provide a new independent filter for the 8" driver.

My questions are:
1. Will having the low pass (150 Hz) section of the stock crossover unterminated cause any problems with the rest of the driver's performance?
2. Does anyone have a diagram/schematic of the stock LSi15 crossover? I'd like to see the component values for the 150 Hz low pass section for a possible outboard passive filter.

All this is reversible, in case it doesn't work out or I want to sell the speakers. This is my first post and any comments or help for you Polkies out there will be appreciated!

heiney9

It's going to be very hard to improve on them IMO, unless you are true electronics guru. But knock yourself out, just don't f**k them up, the replacement parts are expensive not to mention ruining a perfectly good pair of working speaks.

The link to the schematic

http://www.polkaudio.com/forums/showpost.php?p=434888&postcount=17

H9

P.s. If you attempt it alteast document it and post your findings, etc.

dcgl22

H9, thanks so much for the schematic link. And no, I aint no guru, just a tinkerer. My goal is not to *uc* up my speakers which is why I'm planning on a non-destructive concept here. They should be easy to return to stock if this little foray gets me nowhere. Nothing ventured nothing gained...

If the results are worth mentioning, I'll be sure and report in a post. Thanks again for your help!

Frank Z

I'd suggest experimenting with more/better amplification before performing any mods.