Here is what you do. Go out to the car, remove the rear floor mat, lift the bigger door in the floor, grab hold of the big plastic floor box holding the jack, and lift it from the edge closest to you while standing in the hatch opening. It is hinged and will tilt up, revealing the whole underseat area.

On mine (no nav system) there is an amp to the right, and some sort of electronics box to the left, but the middle under the rear seat is empty. Should be big enough to have that JVC sub under there. HOWEVER, I do not see how you could slide it in! There is a black sheet metal spar right in the way.

It would probably be easier to mount the subwoofer by removing the plastic tray to the far right or far left, as there is plenty of room there and it is completely accessable.

 

If there is actually enough space to hold that sub in question in the spot, you could aways remove that black metal brace, put the sub in, then put the brace back on. To do this you have to remove a couple of 10mm bolts that hold it in, but the harder part is you also have to remove the side panels as well. Not that hard, but just more work to do.

 

I am not sure, but you may have to remove the two seats and the carpet to get that sheet metal piece out of the way. It is all part of a big thing.

 

I am trying to install a sub and amp into my car by tapping into the factory amp. I am just wondering if anyone knew what colors the rear speakers were.

 

In answer to my own question the best way to find out what wire from the amp goes to what speaker is to take a 9volt batter and touch the wire from the amp to the wire, you will hear a light pop in the speaker that the wire correspsonds to. From memory the back speakers i believe were red and then gray, but double check that first. Other than that adding another amp and sub are really easy.

 

That is an excellent installers trick. However, that doesn't tell you polarity unless you can see the actual movement of the speaker cone. If the cone pops outwards you know it is positive. If the cone sucks you have inverted the polarity. Anyway, I did download the actual wire schematic from the online service manual, so that is how I found my wiring. If I can find it I'll post it.

 

Interesting. Where do you find the online service manual, or better yet, where can you get one on a CD?

 

how much power does the factory amp have? i thought about having my subs run off the factory amp, but i didnt think there would be enough power, so i had it run off a seperate 2 channel amp.

 

Just did a wire check today. The rear left speaker wires at the amp molex connector are a red one and a gray one. Also on the other molex connector there is a purple wire which is switched to go on w/ the stereo and gives a convenient place to splice into for ACC+ for new sub amp turn on. Dang, looks like I will have to run power wire all the way to the battery for proper current.

 

Your DIY was the only one I could find to help put in the sub. Took me about four hours to install in my fiance's 330, most of which was figuring where to run wires, mount amp, and secure sub box. The sub is an Image Dynamics OEM 12 in a 1 cu. ft. sealed box and amp is an RF 450S. Truth to tell I wasn't expecting much from just a sub addition, but since I had these pieces lying around from incarnations of my Acura CL-S an TL installs, I figured what the heck.
Well, in short, I am rather shocked and confused at how much better the 'Premium' system now sounds. Before the sub install, the deep bass was lacking, the midbass was illdefined and bloated, and the midrange/vocals sounded muddy and inarticulate. In fact, I would try and fiddle w/ the sound shaping everytime I passengered in the car, but failing to get an inoffensive sound I would end up just turning the volume down.
Now, there is good tonality - to me most important -, adequate transparency, fair/good bass defintion, and actually excellent sound staging. I'm actually a bit peeved as I've worked pretty hard on my own cars' installs w/ Eclipse HU, multichannel amps, and CDT/Focal components installed in kick panels. What are the odds that this Lexus POS system w/o proper sound deadening, mids and tweeters 18 inches apart, and a tiny amp w/o proper x-overs, match or exceed my other installs in some areas? My own systems still have better transparency and bass impact, but soundstage is at about mid dash height. The Lexus w/ sub has a stage at head height and forward to the front edge of the windshield. I've never personally had luck - proper tonality - w/ tweeters mounted in the sail panels, but damn if it doesn't work well here.
Warning. I did try reversing the polarity, and the sound became more thumpy, but more muddy at the same time. It was the sound I was expecting to get w/ just a sub added to the system. Needless to say I switched the wires back and there is just some kind of synergy here that makes the system simply enjoyable to listen to. Cannot recommend this upgrade more.

 

most lexus oem systems are lacking in the lower end. the stock rx system lacks bass, and adding a system does improve it a lot. i have a RF 900S amp pushing two 12" P3's wired in parallel. The system is backed up by two monster 1.0 farad caps. I run the whole thing on the stock battery and stock alternator. i have run the whole system with the amp crossover turned up halfway, the bass on full power, radio volume on 37, a/c running at full blow, and no power loss. i ran the same setup on a previous car and toasted the stock battery in 1 month. as much as i complain about the rx330, the car is suprisingly well damped. i still havent heard any vibrations, rattles, or loose panels, even with all the pounding from the subs. the electrical system also holds up very well, still on a stock battery 1.5 years after the install.

 

lucky you! I have rattles coming from spring hinges adjusters from the rear right passenger seats. Can't get ride of this annoying noise... I hear it after the car goes over little bumps that vibrate the car...sucks...But wont hear it if I turn the volume up.

 

I'm glad I remembered enough detail to get you through. I took apart a lot of my RX330 interior when I was modding it many times, but its much easier to do when you see it with your own eyes. When I posts that I no longer had my RX and was just trying to recall what I remembered

 

Can someone tell me what color wires I should hook the LOC to?