Recently one of the stock speakers in the front (right door) burned out, and I had them replaced with a set of Alpine SPS-600 coaxials. My old tweeters still work well, and the installation professional left them connected (so the tweeters on the new speakers aren't being used).

Here's my concern. The information inside the box had this warning, which I had no opportunity to view before the installation was done:

"This product contains a high performance tweeter.
If there is a tweeter already installed in your car, then you must disconnect its terminals.
If you leave the original tweeter connected and connect this product in parallel, then a fault may develop in this product, so you are strongly recommended not to do so."

When I questioned the installation professional about this (he has over 20 years of experience in radio and speaker installations), he said this wasn't a concern since the new tweeters aren't being utilized (so the sound isn't simultaneously running over two sets of tweeters in front).

I still have some reservations, since I have no experience with speaker installations and don't know who or what to trust. Should I be concerned about speaker damage, or is this speaker configuration safe?

Also, are the rear speakers the same size (6.5") as the front ones? I've been considering eventually upgrading the entire speaker system. It would be good to know if (down the road) I could move these coaxials to the rear and install components in front (which I wonder if I should have done in the first place). But for now, I just want to make sure I'm not going to damage my new coaxial speakers by using them as currently installed.

 

You shouldn't have to worry about speaker damage. I've seen many setups where someone installed speakers such as yours and either completely removed the tweeters from the new speakers or just disabled them altogether.

FYI the rear speakers in your car are 6x9's so, no. The front speakers will not work very well in the rear.

 

Not unless the LS is a sedan, on the hatch they are standard 6.5" just like the fronts.

My concern would be why would they disable the tweeter on the coax, if anything leave the stock tweeter disconnected, or connected, sometimes a second set of tweeters up high can help "brighten up" the highs and the only issue will be the phase shift, [in highs] because of the tweeters being so far apart, [or one being closer to your ear then the other] and that can't hurt anything.. 94

 

I always leave the factory tweeters hooked up alon with coax. But I wouldn't worry in your case

 

Well, I guess I assumed the LS was a sedan. My bad.

 

Sorry, I should have specified. It's a hatchback. On that note, you've brought me some good news about the speaker size.