Looking for a little more boom from the basic stereo, so I was thinking to add a 40 watt aftermarket amp ( Alpine ) to power two 6 X 9 speakers in ther rear deck .... will somethng like this improve the system ?

 

In all likelihood all you'll end up doing is blowing the rear speakers. Most factory systems closely match the drivers to the amp. If you want more volume then replace the speakers with something along the lines of the Boston Acoustics SE series which are very efficient and designed to produce high quality sound with good volume from a low powered system. If it's bass you want then you need to address the subwoofer not the rear speakers.

 

I may have not been clear, I was thinking of adding two extra speakers in the rear deck behind the rear seat, and powering them with a separate amplifier.

 

I would think that would create a very odd sound stage. Exactly what are you trying to achieve? Is it more volume, more mid-bass?

 

I want more volume mostly, as I drive on the highway ioften with the windows open.

The sound in the front is quite good, and most of the time it's fine. Its just every once in a while I do like to turn it up LOUD, and the stock sound system just doesn't sound very good loud.

 

The real problem is that the speakers and amp are pretty closely matched. If I were going to address that problem I'd get a nice 4-channel amp and replace the front and rear speakers with good quality aftermarket speakers. Run the speaker out from the stock setup into the high-level inputs on the amp and the amp output to the speakers. You have a budget in mind?

 

I still don't think you are getting the direction I am heading here ....

I am going to leave everything as it is, unchanged and add one NEW amplifier and 2 NEW speakers in the back.

 

Yes, I get that. My point is you would have a very odd soundstage with a set of speakers in the rear deck along with the stock system so while it would be louder, not sure it would sound strange. There is no physical reason why you couldn't do it. Not sure how to get the signal to the new amp though.

 

I would not advise going this route. Adding another pair would not make the system any better in the same way that adding a third pair of wheels would not make the car any faster. While the stock LS system is by no means fantastic, it is at least tuned well for what it is. Placing more speakers in a horrible location like the rear deck and running them off the factory amp signal (which you are going to have to do if you plan to run them off an aftermarket amp but keep everything else factory) is going to be nothing but destructive to that harmony.

 

Well, it would make the system louder I just don't think it would sound very good. My original recommendation stands: if you want more volume then get a 4-channel amp and a good set of speakers (I put components in front and coaxs in the back of my '00 ES300). You will get more volume AND superior sound quality.

In my system I installed Boston Acoustics 6.5" front and rear. Even with the stock amp it rocks. Sound is much more open and airy, tininess is gone, harshness is gone. Slight increase in volume. When the amp goes in then this thing will be almost like a whole new stereo.

 

if you havent decided yet . the best solution would be to switch from your 100 watt preimum pioneer amp to the 330 watt 2005 ls430 mark levinson amp. ......... the 2005 ls430 is one of the few lexus models that you can switch between pioneer amp and mark levinson amp with no problem. the switch just involoves unplugging your pioneer amp and plugging in the mark levinson. after installing many of these amps i recommmenfd you leave the key on accesory to let it initialize with the pioneer head unit for 5 to 10 miniutes before turning it on. . yes both mark levinson and the premium pioneer systems both have the SAME EXACT RADIO. hence the amplifiers are interchangable. also i think the pioneer speakers can handle the 330 watts from the mark levinson amplifier better than the mark levinson speakers. so no need to do all this aftermarket stuff. the solution is staying with the upgraded factory stuff.