03 jbl synthesis system

[sal16]

so im gonna be changing out the system for a coworker of my brothers. im gonna put mb quart speakers and subs and fosgate amps. my questions are:
1) does the jbl system have an external amplifier? if so, where is it?
2) is the harness for the radio a regular toyota harness or some other one?
3) where can i get the signal for the 4 channel amp? im gonna use the output of the 4 channel to go to the sub amp.
4) what give the rear tweeters power?
thanks.

 

[Nerve]

Can only answer the first one for yah.
Yes, the JBL Synthesis uses an outside amp. It's located in the cargo area right next to the sub.

You can see a pic of the actual assembly on this thread

As I understand it, you'll have to take out the that rear panel to get at it.

That's all I can give you on the matter.

Have fun with it.

 

[sal16]

thank you. that helps a good bit, but how do you lnow that the speakers are off that same amplifier? thanks.
sal

 

[Thai]

For Harman International car audio systems, they usually use just one amp to power everything. Harman International includes Harman Kardon (BMW & Mercedes), JBL (Toyota), Infinity (Chrysler), and Mark Levinson (Lexus).

In all of these car systems, only one amp powers the speakers and subwoofer. My BMW M3 has one Harman/Kardon amp that powers 12 speakers (2 of which are 6x9 subwoofers). My brother's Lexus LX470 has one Mark Levinson amp to power 11 speakers (one of which is a 6" subwoofer). All Lexus vehicles have just one Mark Levinson amp to power the whole system.

Not many OEM audio systems have separate amps for their speakers. Instead, they have one amp with multiple channels (5-8 channels!). Mark Levinson (in Lexus) actually bridges two channels together to power a few their bass speakers.

BOSE is the only one that still uses many tiny amps to power their speakers. BOSE would have the headunit being the digital processor, while each of it's speakers would have a tiny amp powering it.

However, with the advancing digital processing and spatial audio production, the need to better configure the power distribution leads to the one amp model. BOSE has now shifted to the one amp model, especially in higher end cars. This allows them to concentrate on one amp and then specifically dividing each channel for a purpose (both in power and signal).

So, basically, yes, your JBL system in your 4runner has just one amplifier for all your speakers.

 

[sal16]

thanks thai. just wanted to make sure that toyota jbl wasnt different than ford jbl. so do you know where i might be able to get the signal for the 4 channel amp? should i get it from the deck or from the amp input. the thing is this guy wants to keep the center because he likes the sorround function. how does the deck output the signal? is it speaker level or low level? is the harness on the deck like other toyotas or is it like the ford jbl harnesses? thanks.

 

[Dude]

should i get it from the deck or from the amp input. the thing is this guy wants to keep the center because he likes the sorround function. how does the deck output the signal? is it speaker level or low level? is the harness on the deck like other toyotas or is it like the ford jbl harnesses? thanks.

The 03' has a new harness adapter versus previous years. If you are going to tap the speaker leads, I would do it on the pre-amp side coming out of the headunit and before the amp. There is no need in getting a signal that is amplified and is passed through a crossover.

Only problem is that the pre-amp signal is a low level lead versus the post-amp signal. I have seen a couple of threads elsewhere discussing this matter and one installer suggested soldering RCAs directly to the pre-amp speaker leads and then running directly into a JL amp that accepts 1.5-4V variable signals. My first problem here....you have to chop the OEM harness....bad for putting back to stock. Secondly, I have not seen anywhere where someone measured the output voltage. If the voltage is too low....you will need to boost the signal first and then convert to an RCA connector.

Given the above discussion, any thoughts on this approach? I was thinking if you could buy an extra OEM harness and then a Metra-type "any headunit to OEM harness" adapter, then you could put the two together and make a "patch harness" that sits in between the OEM harness and the head unit. In other words, new OEM harness to the headunit and to the METRA harness, Metra harness to the existing OEM harness......Then you could split out the Pre-amp speaker leads and do whatever you want without chopping the factory harness. Then if you want to sell the vehicle, just remove the piece along with your equipment and it is 100% stock.

If you are going to do this install, do you have a voltmeter to measure the pre-amp speaker volt levels? I'm just guessing that it is around 1V or so.

Anyway, the approach I would use: Chop the OEM harness and physically disconnect the pre-amp leads for the front and rear door speakers. Run them into a converter of some type and maybe a signal booster as well. Then send the signal to the aftermarket amp. Run all new speaker wire of a suitable gauge to all speakers and sub. The center and rear pillar speakers will still work....although, I think once you get the MBs in there....why muck it up with crappy, under powered speakers? I actually have my JBL stock system with the surround turned off and it sounds better. I personally would unplug the factory amp and eliminate any kind of weird staging that would come from these speakers.

OH YEA....after you try all of this...let us know how it works

 

[Greenhorne]

I personally would unplug the factory amp and eliminate any kind of weird staging that would come from these speakers.

So does the "staging" (attenuation of the rear speakers and such) of the system happen at the head unit or the amp?

 

[Thai]

I would guess that the spatial imaging of the system comes from the amp itself. Crossovers are also included in the amp. As was said above, the signal after the amp has already been filtered by the amp.

 

[sal16]

well, i really dont want to chop up the harness so i guess i'll just get the plugs from the dealer and make my own harnesses. if it is a low level, you can just solder rcas to it, then amplify the signal to a known voltage, say 4 or 6, and then connect from the signal amplifier to the power amplifier. i'll check the voltage and let you know when i do it. i dont much like the idea of leaving the center in either but he says he really likes how it sounds. i like it better without but its his car. as for the pillars, i will be putting in mb quart tweeters there. the signal to those seems to be a full pass signal since they have the high pass filter right there with the tweeter. so i'll be getting the same amount of power to it but crossed over slightly differently and it will be an mb quart tweeter. the only stock speaker staying will be that pesky center. i really hope i can get the plugs from the dealer, then i just have to get the pins and make my own harness. if not this, then im still not gonna have tocut the harness. this is gonna be tricky, but i think i can do it with the right pins.

 

[Dude]

i really hope i can get the plugs from the dealer, then i just have to get the pins and make my own harness. if not this, then im still not gonna have tocut the harness. this is gonna be tricky, but i think i can do it with the right pins.

I think I understand...

plug=the actual plastic piece that holds the wires that plugs to the radio?

If you can get that harness, you are set......especially if it has all of the wires. If it doesn't have the wires, that is a much bigger process. I know with the Metra harnesses it is pretty easy to remove and install extra wires into the plug. But some of these factory plugs are actually molded around the wires. So trying to mess with it usually destoys the plug.

If you get this harness, you have to give me shout to let me know how it goes. I am waiting in anticipation of some good news.

I also found this TA03 at Scosche :

I talked to one of the techs about it and he was not very helpful other than mentioning that "it doesn't seem to work that well on some models"....of course, I think he started that sentence with "when I was doing installs at Best Buy..." Nuff said.

I can't tell from the picture, but it looks like this is a male plug. Now if the headunit is a male plug...where does this go?....my only guess is at the end of the OEM harness before it plugs into the amp. Even so....I still think you will need to boost the signal.

And if there is any doubt that I goofed off at work yesterday....here is another interesting little product that I have been following:

This unit plugs directly into the back of the OEM headunit in the external CD changer controller jack. Read here to see some of the questions I posted to their tech forum about a 4runner install. If I can get this installed and add some aftermarket amps and speakers, I will be set.

 

[Greenhorne]

tweeter. the only stock speaker staying will be that pesky center.

Why keep that one? Is it to difficult to replace?

 

[sal16]

that plug is a female plug. most radios need a male plug to plug into them, so it might just be the plug at the amplifier. i'll take a look at the car and let you know. maybe i will change the center, but they dont typically sell individual speakers.

 

[sal16]

i looked at the picture a little closer...what it is, is a harness that plugs into the original harness and into an aftermarket deck. those rca's are male ends so they plug into the female output of an aftermarket radio.