I just completed a stereo upgrade and here are my thoughts. My constraints were I wanted to retain all functionality of the stock head unit, and all speakers including sub had to fit in the stock locations (my trunk is a trunk, not an enclosure).

Speakers:
Front door speakers are JBL GTO628 rated 60 watts RMS per channel, efficiency 92 dB, 50-21kHz. These speakers have nice sound all the way from the bottom to the high end, and at 60W rms they have plenty of volume. The tweeters have a 0 or +3dB switch which I left at zero since I was maintaining the dash tweeters. I'm giving these speakers +6dB bass boost from the amp. I only wanted +3, but the amp didn't give me the choice. A downside to these speakers is that the size of the magnet and terminals requires a couple of 1/2" cuts with a dremel in the bottom of the speaker opening in the door and rolling down the metal. These are nice speakers if you don't mind making some cuts in the door metal.
I maintained the stock dash tweeters for now because they weren't in my plans. Originally I was just going to disconnect them because the door speakers had them, but without the separation, or presence, or whatever you want to call it wasn't as good. Leaving them connected gave too much treble, so I added three 1 ohm 5W resistors in series with each which gave some attenuation but still gave some fill from the dash area. Eventually I'll replace the stock tweeters with aftermarket.
For the center speaker I used an Infiniti Kappa 3.5" rated 35W RMS. The amp high pass filter is set at 100Hz for the center. That was a pretty simple install.
Rear deck speakers are Clarion SRG1621R, 35W RMS, 30-30kHz, 4 ohm. These sound nice, but I wish they had more midrange punch and a little less treble.
The sub remains stock for now, being driven by an aftermarket amp. The stock sub is reated 40W, but with the low pass filter set at 200Hz, it can put out a higher SPL in the narrower bandwidth without exceeding the rating. I'm thinking about a way to put a nice aftermarket sub in the rear deck, but that will be the subject of another post.

The amps are Audiopipe APSM-4050 front and rear. They are rated 80W RMS per channel (4) @ 2 ohms, or 1000W each for you power freaks. All speakers are 2 ohm, with the exception of the Clarions which are 4. The gain on each amp channel is set appropriate to the speakers. IMHO, these are very nice amps if you only need to blow out your eardrums and don't need to blow the glass out of your car. I was a little leery of the .05% THD (.01 is achievable) and the 80dB SNR (90 is achievable), but at the gain I'm running the sound is very clean. There are no pops or thumps when the amp turns on and off. One thing I really liked is the compact size, which allowed mounting one in the stock amp location. The one in the trunk is hardly noticeable other than the bright blue power LED. Some nits with the amps are that the gain, LPF, HPF, anc bass bost controls are on the back side of the amp, so if you want to adjust those you need to dismount the amp. Also it is fan cooled which is the price of a small package. The fan never comes on at the power I'm outputting, and if you're using that kind of power you're not going to hear the faan anyway.

Some other notes on the install:
If I had it to do over I would have spliced the stock amp inputs to the rear speaker wires to run head unit output to the rear amp. I ran the signal to the rear from the head unit down the center hump to the back. I did that because I wasn't originally planning on replacing the stock amp. Rinning the signal wires down the center had me picking up ignition static, either from the amp control wires or the airbag wiring. I then had to shield the signal wires and ground the shielding, which eliminated the static.
Overall the system has a very clean, balanced sound. The sub has plenty of capability for the volumes I listen at, but you hear it, you don't feel it. At the limit, the rest of the speakers would overwhelm the sub. One of the criteria for choosing the door and rear deck speakers was low frequency response, which takes some of the load off the sub, allowing to run at a narrow bandwidth which allows it to put all its effort into the deep notes. It seems to work.
Overall I'm very happy with the results. I'm going to listen for a while and decide what I'm going to do with the sub and tweeters.

 

I'm glad you like it. You could've saved some money not doing the center and rears. The Infinity 3.5" is not really an upgrade over stock and the stock center is barely used except for navi.

Having good sound quality means being able to cover all of the required frequencies and transients with low distortion. From what I gather, you kept the stock sub.... You will get tired of this eventually especially with the rest of the system upgraded. I've had at least a pair of 12s since the car was new in Dec of '05 and even then I did not know how much of the music I was missing until I had a system capable of the lowest of notes early this year. My trunk actually is an enclosure and I've lost maybe 10% of it's capacity (no box) at most with a pair of 15s. My goal was to have a great SQ system that will go loud and take up little to no space.

 

Good to hear that you are happy with it. Like IHC said, it wasn't the best to upgrade the rears and the center. I have the stock center on my setup turned off and the rears stock with stock amplification for rear fill. My fronts are Morel Maximos getting 150 watts each and I can say I don't miss the center and the rears are good how they are. I did put a sub and box in the trunk and while the increased low end is great I hate that with the box and my daughter's stroller in there I have space for nothing else. After reading on IHC's threads on Infinite Baffle I bought a different sub and will hopefully get it in soon in an IB setup, I think that an Infinite Baffle would be something that would be good for you to look into as well, giving you the increased low end while not taking up so much space

 

Now that I'm done I agree there wasn't any real need for a new center. My thought at the time was to maintain some sound from the dash area with the tweeters disconnected, but I ended up reconnecting the tweeters. I'm glad I did replace the rear speakers though. Maybe the originals were worn out, but they managed to sound fuzzy and tinny at the same time, and the replacements weren't expensive. With them being around half the power of the fronts they give the right amount of fill for my tastes.

I'm mulling over my options for a rear deck sub since I'm wired and amped for it. After examining the rear deck area I don't agree that a rear deck sub would be an infinite baffle set up. The measurements of the metal enclosure around the rear speakers and sub are about 36" X 4" X 11", for a box volume of .91 cubic feet, but maybe not in the optimal shape. Functionally it's not a sealed box because the openings at the ends and bottom, but it's not really ported because the rear shelf and trunk carpet doesn't allow porting. An idea I've been considering is to line the interior of the rear deck cavity with dynamat or something like that and either seal up the holes or devise some kind of functional port. It would take quite a bit of patience to lay down the dynamat working through the speaker cutouts. Most subs would also require enlarging the hole under the sub cutout. I haven't searched to see if anyone else has tried this. I would appreciate any thoughts on whether this is a rational idea or why it wouldn't work.

 

Putting a sub in the rear deck has been tried many times and its not worth the effort. If you want infinite baffle, build a baffle behind the seats.

 

Well, that was technically illuminating, but I believe I'll run the equations myself. I don't want an infinite baffle, I'm talking about a sealed or ported enclosure integrated into the rear deck. I'm leaning toward a ported enclosure, which has the same efficiency as infinite baffle and better control of reflected sound. A 40 cubic foot trunk couldn't be considered 'infinite' baffle. I successfully incorporated a ported enclosure in the rear deck of my Lexus that works very nicely, and the TL looks more amenable to the setup. Of course I haven't done any calculations yet. I challenge those who say the rear deck sub can't work to post their dimensions, materials and calculations. If someone uses the plug and pray system how can they expect it to work?
Besides, why would anyone want a car you can't carry skis in?

 

Ah, you're one of those smart sarcastic guys. I was trying to save you some trouble but since you know everything, go for it.
First, search. You will see where others have tried just dropping a sub in the hole and some have tried turning the deck into an enclosure. It does not work for several reasons.... It's almost impossible to seal up, it will rattle no matter how you treat it, you can't go larger than stock and no one really wants to do all of that work for an 8" with a little more throw. What do you think will sound good in <1' of airspace in a ported enclosure tuned for music?
Ported does not have the same efficiency as IB. It's been my experience (since I've run sealed, ported, bandpass, and IB in a TL) that IB gets just as loud or very close to the same SPL as ported at the same power but ported will ultimately get louder since it will take more power. IB will have the same SPL as sealed but it will require half the power to reach the same SPL in the lower frequencies. Ported does not have "better control of reflected sound". Anything with a box will have to deal with back waves. IB does not, which is one of the pluses. Stray waves trying to get through the cone in a box setup is called distortion.

You don't have a grasp of what "ported" means. It's not a sealed box with a hole punched in it. The port is tuned to a specific frequency according to the size of the enclosure and the sub's T/S specs.

Our trunks are not 40', they're 15.5 cubic feet. It's not a true IB but it's large enough to act as such. As long as it's larger than the Vas of the sub it's going to act very close to a true IB. I'm running two 15s in this arrangement. If there was an issue with trunk air space I would probably experience it.


Looks can be deceiving. I'm sure it sounds good to you and that's all that really matters but how many high end systems have you heard?
"Plug and pray"? You're assuming a lot in that statement and you're insulting a lot of us on here coming in here with that kind of attitude. Do you think the award winning TLs on this forum haven't thought of the exact same thing you think you came up with? You admit you have not done your "calculations" yet but you're calling out everyone who has attempted this before you???

You're running bass boost on your comps and two sets of tweeters up front and coaxials in the rear. This is not the correct way to do things.

In all honesty, displacement rules whether it's SPL or SQ. I have extremely accurate bass with ultra low distortion. At moderately loud volumes you can't see the 15s moving. This is important at reducing distortion. My original statement was to point you in the right direction without wasting 2 minutes of my life writing this out.

Not everyone skis and those of us that do have a second car (mine is AWD) that's much more snow friendly than a TL. I go water skiing every summer but skis go in the boat and the boat is not pulled by the TL.

I don't like having a huge box taking up the whole trunk which is why I went IB. Both subs plus the baffle weigh less than 45lbs and take up only a few inches of trunk space. Never once used the skipass before so it really didn't matter to me to lose it.