new to forum -long time Polk fan

sbb2112

The SDA-SRS's are about to go down for a rework of the crossovers and new tweeters. I have a center channel speaker that was starting to not work the way it used to. When calibrating with a mic, it kept needing about 3-5 dB more than any other speaker and then it sounded flat. I would like to put it back in but not sure how to pin down what might be going on. Any thoughts?

Dennis Gardner

You should eliminate electronics first by swapping out the center with another speaker to see if the flat sound is actually speaker related. It sounds like it might be a tweeter/crossover issue. I will also inject that when my receiver's start to go out they required more setting volume in the bad channels.

sbb2112

Thanks Dennis. I had that thought too. I put the Klipsch center and all was back to normal adjustment dB wise and highs were normal. I will see what is in the CS400. I haven't taken it apart but the tweeter is between the 2 drivers in a molded plastic surround. Hopefully its not all one piece.

sbb2112

I hooked it up and there is sound from the tweeter and the drivers. Very good possibility the crossover is failing or has a component(s) out of spec.

sbb2112

Got the 194 tweeters for the SDA SRS's and thought I would put them in for a couple days before I took the crossovers out to get rebuilt. It seems that the plastic frame is designed a little different than the SL2000. The lip sits on the top of the front panel and the bosses on the back of the 194's are not flush to the rim like the 2000's. The boss thing is just not good from a fastening standpoint. I didn't tighten the screws once I saw that the rim wasn't going to bottom out because its setting on the lip around the perimeter. Even if the rim did bottom, the bosses are short and will crack over time without some support from behind. I tried a search to look for some suggestions on how to mount these so the bosses don't crack and the rim seals up but got so many results that weren't really pertinent to a solution. My thought was to glue a flat washer on the bosses to bring them up to flush and get something non compressible like sheet rubber for the gasket. Looks like the gap is about 1/16" or so. Does anyone have better thoughts or a solution to this? I also had been reading that the installation of hurricane nuts or plates is a recommended mod but there are already threaded inserts on all the tweeters now. Not sure if I should leave them alone or not. I haven't ever had these apart other than to pull the crossover to eliminate the polyswitch a long time ago. Bought these new and so they came this way.