Some Audio System Installation Questions--

ecsevo705 · Post by **ecsevo705** » 22 Aug 2006, 13:39

Hopefully these havent been covered- I used the search function first so hopefully these are new Q's. Ive been using Crutchfield.com to look for a new system for my 1995 850 turbo wagon. I have the deck, front door/rear door speakers picked out, and it comes with everything to do the job which is awsome and a main reason why Im using Crutchfield. One of my questions is- I dont have enough $$ to buy the new speaker set now, but I can afford the deck (Pioneer DEH-P3800MP). If I install this alone, will I notice a big difference from my stock unit? Also, what is the Volvo part number for the dash pocket that fits the best? Ive heard the ones Crutchfield supplies do not fit that well. Also, will I still be able to use my stock Volvo 6-cd changer with it? One more - in way of speakers would you go with Boston Acoustics S45's or Polk Audio db 400's? They seem pretty evenly matched and are the same price. Im pretty noob so any advice you can offer would go a long way. Thanks so much.
Erik

l33tDad · Post by **l33tDad** » 22 Aug 2006, 13:47

I bought a Kenwood deck from Crutchfield for my '93 850 and the pocket they provided with the kit works perfectly fine for me. I did find that it's best to install the pocket ABOVE the deck as opposed to what they say though. The deck will fit a lot more snug, won't move as much and stays a bit cooler. As far as speakers, I disconnected the dash speakers, am running Kicker 5.25" speakers in the front-door and stock speakers in the rear. Works fine for me. I may at some point upgrade the rear speakers, but I'm happy with what I have now. I don't have a clue about the changer though.

If you have a cd-deck with changer now, why go aftermarket? I only did for a custom install of my Satellite system (Sirius).

ecsevo705 · Post by **ecsevo705** » 22 Aug 2006, 16:42

The reason I want to put a new system is becasue the current one, as long as it has lasted, is kinda of dead. No clean highs, no bass, its good for listening to the radio, but I reallllly love my music. Also, I can never really let anything sit stock for long... Any other suggestions? Thanks
Erik

l33tDad · Post by **l33tDad** » 22 Aug 2006, 17:33

It's all good, just curious. Like I said, the pocket that came with the kit from Crutchfield worked pretty good for me. If you're buying from Crutchfield, it's free anyway, so I'd give it a shot..

Post by **robert213** » 22 Aug 2006, 22:19

Check the ohms rating of your OEM factory speakers. If your door/dash speakers are 8 ohms, do not simply replace with aftermarket 4 ohms speakers.

When door/dash speakers are wiring together in a parallel circuit, the ohms resistance at your stereo amplifier still must be greater than 4 ohms.

Ohms Law for parallel circuits.

8 ohms door speaker and 8 ohms dash speaker

1/8 + 1/8 = 1/Total_R
1/4 = 1/Total_R
Total_R = 4 ohms
--> Stereo Amp will run cool

8 ohms door speaker and 4 ohms dash speaker

1/8 + 1/4 = 1/Total_R
3/8 = 1/Total_R
Total_R = 8/3 (or 2.67 ohms)
--> Stereo Amp does not receive sufficient resistance -- will run HOT.

Robert: You are correct. I found that the front dash speakers are 8 ohms and wired directly to the radio. The front door speakers are 4 ohm and are also wired directly to the radio.

Here's the tricky part: The Rear door speakers and the rear deck speakers are both 8 Ohms and they are wired in parallel as you have warned against.

The Crutchfield Rep said that replacing a 8 Ohm with a 4 Ohm speaker when wired directly would be OK. He said that so long as the amplifyer saw at least 4 ohms or greater things would be alright.

THIS DOES NOT HOWEVER APPLY TO MY REAR SPEAKERS WHICH ARE WIRED IN PARALLEL. If I replace both of the 8's with 4 ohm speakers the radio will see only 2 Ohms which I feel, and as you have pointed out, will cause the amp to overheat and burnout eventually.

I have already replaced my amplifier chips in my radio once already and do not want to have to do it again.

SO, what is a fella to do?? Anyone have a source for 8 Ohm car audio speakers??

I am going to call the same rep at Crutchfield on this parallel wiring situation and see what he has to say for himself.

Anyone??

You have a couple of options...
1) solder in a 4 ohm resistor in front of the "+" terminal
2) unplug the connector of one of the speakers, usually door speakers.

Double-check ohms impedence at amplifier with volt/multi-meter.