How can I find out more info on my factory car stereo?

[MichaelD]

Such as RMS per channel, impedance of the factory speakers, etc?

I want to replace the factory "separates" with some aftermarket component speakers, but I'd like to find out the above info first.

For you techies out there, most aftermarket car speakers are a 4-ohm load, or have a 4-ohm total load (in the case of separates) but sometimes factory speakers are 8-ohm or even 16-ohm and designed to work with the factory head unit.

If you put a 4-ohm load on a reciever designed for 8 or 16 ohms per channel, you'll prolly blow the head unit. Not good. I'd like to find out more info. The vehicle is a 2001 Isuzu Trooper. Thanks!

 

[MichaelD]

I know this is a really weird and hard-to-answer question. But UPUPUPUP anyway.

 

[Grinchy]

A google search will probably solve your problems, but anyway I'll add what is generally true.

If you have the 'base' model stereo, you are guaranteed to get 12 W rms out of it, with maybe 35-40 peak. This is because to get more W out of DC requires an AC inversion, and that requires a separate amp, so basically ALL head units (OEM and aftermarket) have a simple IC which amps to 12W and that is it. This is of course assuming 4 ohm speakers.

Now, some newer, up model cars have separate amps on different speaker groupings and treat the head unit like you would an aftermarket with rca outputs and separate amps. Sometimes the OEM chooses to amp the highlevel (speaker outs), sometimes they actually do it right and use the low level (rca) outs. Sometimes they do both.

My car they actually do both. What a mess.

If your car sounds good now, there is probably additional amping somewhere, a base head unit with the 12w x 4 is not ever going to sound good, especially in an SUV.

Sounds like you're going the right way - new speakers and a sub with a 4 channel bridgeable amp are the best first buys. Later you can upgrade the head unit, use the 4 channel amp for the front/rear speakers, and only have to buy a 2 channel or mono amp to continue driving the sub. And new speakers are going to make a big difference.

Get an ohmmeter and measure the impedence at the speaker - that will tell you what to replace them with. Almost guaranteed a Japanese car uses 4 ohm (and no it isn't a completely accurate measurement because the impedence of the speaker motor changes under use, but it is close enough to get replacements).

Good luck. Be warned, once you start fiddling you will create a giant money sucking pit.

 

[MichaelD]

Thanks a lot, Grinchy. I really don't think this system has separate amps. I'm pretty well-versed when it comes to car audio. I know all about "money sucking pits" as the system in my Accord was one. 600 watts RMS power is nothin' to sneeze at..that's what I had in the Accord; 4-gauge to the battery 1.5 Farad cap, AudioControl EQX, the whole nine. Did it all myself and it sounded awesome, but I had no trunk. I still have all the equipment and will not be putting it in the truck. Whole rationale behind buying the truck was to be able to haul stuff. No more for me. I'm trying to sell the equipment locally and am having NO luck. I guess everyone is "broke" for the holidays. Bad timing on my part, I guess.

Anyway, the factory system is in two separate DIN-sized parts; the head unit and the 6-CD changer. They are mounted right on top of one another in the dash. The factory front speakers ARE two-way separates, that's why I'm concerned about the impedance. But you're right; most Japanese vehicles do have 4-ohm speakers.

I wonder if the factory radio has pre-outs? That's would be nice...I could hide a 4-channel amp behind a trim panel...a piece of 8-gauge to the battery would be sufficient. Ah crap, the bug is biting again!!!! I miss the bass. Boy, do I miss the bass! I love it when my clothes vibrate! :Q I may just wind up removing the factory head unit "just to take a peek at the back" you know? Thanks again. Happy Turkey Day.

 

[d33pt]

i can almost guarantee that your factory head does not have rca preouts.. if it has outboard amps then you might be able to track down the line outs, but otherwise you'd have to step down the high output with a line output converter, which will hurt quality quite a bit, but then you can add your subs/amp.