Lexs400

Once and for all I decided to take the speakers apart to look at them and post the correct information.
so here it is. Both for the subwoofer and the speakers.
Contrary to the many posts that are roaming around in CL about the specs of the subwoofer, the 90-94 Nakamichi are all the same size, 8 inches, and 5 ohms.
NO, they are not 10 inch in 93-94 versus 8 inch in 90-92. same size in all years. I checked with a 1991 to make sure.
Many posts read that the subwoofer is either 1ohm, 2 ohm or 4ohm. None ! it's 5ohm, and I have yet to see an aftermarket sub that is rated 5ohms. they're mostly 2 or 4ohm, so unless there is an aftermarket amplifier installed, I dont see how one can match the stock amp with an aftermarket sub.

The door speakers are 4ohm, rated 20/40watts. These are component speakers meaning only the mid level frequencies (vocal) is transferred to these door speakers, the highs (high treble uppper frequenies) go to the tweeters, and the low frequencies (bass) travels to the subwoofer in the back.
Here are the pictures.

Now, I need more information from others on the Nakamichi Amplifier.
Is there only one amp, that is located in the trunk under the CD changer ? Is there another one besides that ?
How are the speakers fed with power? directly from the headunit or from the amplifier ?
Is there just one amplifier that is feeding the 4 door speakers and the subwoofer ?
Can the cross over the adjusted in the Nak amplifier ?

Lexs400

Here's the subwoofer picture.

Lexs400

For the Schematics of the Amplifier and the headunit, I found this address in another CL thread.
www.technicalhelp4u.com

hitachi

why is it sooo rare to find a clear answer to this question. does the 1st gen ls400 speakers get powered by just the head unit or by the amp in the trunk?? is everyone not sharing this info for some reason? dude when i figure this out im gonna make a ************ post to clarify for anyone in the future who may be wondering...

dicer

One reason info is so difficult, is I'm not sure where to get service information for the sound system on these cars. The way I understand it is the amp in the trunk is strictly for the woofer under the third brake light. They are not going to feed all the extra wiring up to the front of the passenger compartment from the trunk, not only does it not make sense to do it, it would cost a bunch of money to do on an assembly line, and the Japanese are the ones that created LEAN manufacturing.

And since the links below are ALL radio and sound system related listings and no other amplifier is shown, that means the main amp is in the head unit.
Here are parts book pictures you can size up to see. And yes they all shorten up to read the same but they are all different links.
http://www.lexussouthatlantaparts.co...rimLevel=19107

http://www.lexussouthatlantaparts.co...rimLevel=19107

http://www.lexussouthatlantaparts.co...rimLevel=19107

http://www.lexussouthatlantaparts.co...rimLevel=19107

Does your car have the phone option or did it? I saw your other post on here too.

hitachi

so the speakers were powered by the head unit?or theres an amp where the head unit is located? ive changed my head unit but the speakers still sound bad... ive changed my rear door speakers and they also havent changed

dicer

did the car have the phone option?

The phone can and will mess it up. One of mine is messed up by the phone, and not sure how to fix it. I disconnected the phone transceiver and tried tracing wires forward, to accomplish a good trace a lot more would need to come off, I never saw where the wire went to the head unit.
All easy stuff if a person knows whats going on, I just need the correct manual and info.

hitachi

that im not sure of.. i didnt see any phones when installing the head unit or anywhere under the center council trims though..would that be the problem?

its clear that the first gen ls400 speakers have no amp that powers them other than the head unit itself right?

dicer

The phone option can hold the head unit in mute. I have one that is like that, plus my woofer is loose and or torn as its scratchy loose sounding.

hitachi

mines had no phone option i dont think. the problem im facing is that it still sounds the same despite changing my headunit and rear door speakers ,what do you think the problem is?. if i were to upgrade anything else what should it be next? front door speakers or the sub?

dicer

Check wires and connections grounds etc.

I'd use a scope and check my output at the head unit and then at the speakers. And actually since the box that holds the front door speakers is so massive, I wonder if there is some sort of amp in there ??? I don't know. I just wish there was someone that could post some good info on these sound systems.

Scroll about half way down and see where it says 90 to 92 only has sub woofer amp.
http://www.carstereohelp.com/lexus.htm

lextout

i was never a fan of the nak sound and price increase, the pioneer oem always sounded better to me

hairdrmstk

I'm in the process of tearing mine apart. The head unit powers the door speakers. My amplifier for sub is actually on drivers side next to wiring coming into trunk. There is no adjustment on amplifier. There are no amps in the speaker boxes. When you add a head unit, it won't interface with the Nak sub, even if you use wiring harness. You have to use aftermarket sub amp. You can use factory wires to door speaker, either on new head unit, or amp, but they're tricky for me to find. I decided to run new wire, which is leading to it's own issues. If I knew it was this involved, I would have skipped it, but I'm in to far to stop now.

hitachi

look this is what i saw about changing wire speakers.. although i guess it would be necessary to change wires unless the speaker wires somehow become damaged or corroded if corrosion is possible with wire speakers

http://machinedesign.com/blog/5-myth...t-speaker-wire

hitachi

i feel like i should be fine if i change the front speakers and the subwoofer amp and a new sub..which is the only things i have left to upgrade regarding the sound system. i already know what i want to