Newbie Playing With New Head

[old929guy]

Forgive me, I know nothing. This'll be long.

The car is an 89 Mazda 929. The new head is a Kenwood MP342U and it is properly installed and working as designed. The car has six speakers, the head is now driving the two under the dash, the two in the doors. The two on the rear deck are not being driven because they were on a pre-amp used with the original radio. I know I could set the 4 speakers to one channel (ohms would go down to 2) and run the rear deck speakers from the second channel but I'd rather try to use the original setup. The head unit has RCA connectors in the back. I know which connector is used to run 4 wires from the dash to the pre-amp in the trunk area. I think I might also be able to figure out where the power trigger wire is for the factory pre-amp. So, what do I need to do? I want to use the RCA outputs from the new head, wire them somehow to the pre-amp wires in the dash and get the pre-amp to power up and see what I get for sound back there. An acceptable alternative would be to use the RCA outputs in the new head to a new pre-amp and then wire the new pre-amp to the rear deck speakers. From reading the wiring diagrams I think the two rear deck speakers were connected left and right and not in a single channel series connection, i.e. I do not think they were meant as a true sub-woofer setup. The deck speakers are 6x9 and I can't tell if they are three-way or not. My initial goal here is to learn a bit about car deck installs and to make use of everything I've got in the car now. Next minor project is to replace all speakers with some higher quality devices. The car is 21 years old and I commute 100 miles a day so tunes are nice to have. I've got a bare-bones understanding about ohms and impedance (real bare-bones). I may be wasting my time here but so far I'm pretty happy with the install as the car didn't have tunes for the last 8 years now I'm rock-n-rolling with a USB stick and about 4 gigs of music!

Thanks for your patience and support.

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[RJesus 10+ year member]

I think your a bit confused.

Pre-amp outputs are for sending a low 1v-5v audio signal to your amplifier.

The amplifier then amps the signal and puts out xx watts into the speakers.

Your headunit has an internal amplifier that powers 4 speakers. You cannot run the speakers at 2 ohms, as this will cause your head unit's (shitty) amplifier to over heat. (because its built to be 4 ohm stable).

You could play with the old unit, and figure out a way to remove the internal amplifier, and configure an output out of the kenwood to play into the stock headunit, and that can power the speakers.

But as I've said, internal amps are crap.

The best advise anyone can give you is to buy a pair of speakers for your front doors, and amplify them with an external amplifier. I'd suggest checking out ebay or the classifieds here.

You can use the other 4 stock speakers as fill for any passengers you might have.

The difference between an externally amplified system and a stock system is night and day.

 

[RJesus 10+ year member]

Cliffs:

using 2 headunits is more trouble than its worth.

Front speakers are all that really matter to the driver.

Its better to have 1 good pair of speakers than 2 mediocre pairs of speakers.

Buying an amplifier is the best-for-the-money improvement you can make.

Cliffs of the cliffs:

buy a good pair of used speakers for the front and an OK used amp to power them.

 

[nabissssco 10+ year member]

hey old929guy, your a musician correct? I ask because its funny how you guys talk. My friend plays all types of instruments and talks the same way...preamp this, head that....kinda throws me off all the time because just when I think I know what he means he switches it up on me and I was wrong.

The advise given from rJesus was correct.

 

[thericanballer 10+ year member]

hey old929guy, your a musician correct? I ask because its funny how you guys talk. My friend plays all types of instruments and talks the same way...preamp this, head that....kinda throws me off all the time because just when I think I know what he means he switches it up on me and I was wrong.
The advise given from rJesus was correct.

you dont have to be in music to no bout audio. lol.

 

[nabissssco 10+ year member]

you dont have to be in music to no bout audio. lol.

I was referencing the terms used, not the knowledge. Im well aware of car audio and its terms, its just funny when my friend trys to understand what im talking about and uses terms like above calling an amp a pre amp and such...//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[S.B.C. 10+ year member]

topic sounds like a 14yr old girl playing w daddys cawk for the 1st time

 

[nabissssco 10+ year member]

topic sounds like a 14yr old girl playing w daddys cawk for the 1st time

very good point!!!//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[old929guy]

Have to laugh about being a musician! Actually, I am just coming off having been completely deaf for 25 years. Lost all my hearing at age 32 and just had two cochlear implants put in to help bring it back. I'm just trying to get my music on again after all this time. There's a lot of long lost to me rock-n-roll that I'm trying to learn how to listen to again. Hell, for all I know my car system may sound great! I'm just wanting to play around again. My last audio project was install a LEAR 8-Track tape deck in a 56 Ford panel truck. The old beast could wail!!!

 

[nabissssco 10+ year member]

lol, i was just asking man. im glad you got your ears back!