New speakers

[ChiNorm]

20 watt resistors will be fine. The tweeters come out of the top of the dash w/o removing the dash.

[Ben850]

The speakers I replaced are in the front doors, so bass isn't really a critical issue. The 4 speakers in front (2 on dash and 2 in front doors) are linked together, and the 4 in back (2 in rear doors and 2 on rear deck) are linked together. I don't want to remove the dash to replace the good speakers inside. So now I'm left with an option to find replacement speakers at a junkyard, or keep the new ones and put a resistor on each one. I am opting for the resistors, because the new polk speakers really pump life into the whole system. Lee mentioned getting 10 watt resistors, but Radio Shack only had 20 watt ones. Am I protecting the amp sufficiently with installing the 20 watt resistors with the new polk 4 ohm 5-1/4 door speakers?

Just a quick note, The dash speakers are very easy to remove. The grills pry up from the front edge and the speakers are only held by two plastic push pin clips. Less than a minute a side to remove. The problem is, the speakers bodies are a molded plastic Volvo design. I have'nt seen an aftermarket replacement.
Good luck.

[mikilla]

On my 850 the dash and door speakers were not linked to gather and the front door speakers were 4 ohm I suggest you take the front door one out and look on the back

[midimykeys]

The dash and door speakers on my 850 are linked together. Unplugging the positive wire from the door speaker silenced the dash speaker, so I'm fairly convinced their wired in tandem. I installed the 20watt 8ohm resistors, and the Polk coaxial 5-1/4's really brightened up the system! I now look for excuses to drive it.

[NavyMatt56]

Ok, I have been there and done pretty much all of this.

1. I absolutely agree with fazool that placing a resistor in series with a speaker's voice coil. This is not the way to go because your rear channels will sound completely muddled compared to your front door speakers.

2. Placing two 4-ohm speaker in parallel will create 2 ohms of resistance and again, as fazool pointed out, will overdrive your car's amplifier. This will cause your amplifier to run hot, cause premature failure of your amplifier, and possibly blow fuses on a regular basis (fuse 11C/11 located in the driver-side fuse block) .

3. Rear door speakers add little to the cabin sound stage because the mid to high frequencies from the rear door speakers are typically blocked by the driver and front passenger seats. If you are trying to thump the heck out of your vehicle, then go for it. Just don't expect clarity from them.

I highly recommend installing quality 4-ohm rear deck speakers, disconnecting the rear door speakers, and call it a day. If you pair the rear deck speakers with quality component speakers (tweeter and woofer are separate) in the front doors, you will see a noticable difference over stock. If you install an aftermarket, 4-channel amplifier between the radio and the speakers, you will see a significant difference over stock speakers.

[kcodyjr]

If indeed your front door and dash series are in "tandem", or rather in series as you've described the behavior, the dash is completely flattening what little bass the door speakers can produce, and a good bite of the midrange as well.

From the factory, the front dash and doors are independently wired to the head unit, and indeed have their own separate pins. With the OEM amplifier in the car, the dash are still driven directly from the head unit, and the amp powers the other six. Hence, the front door speakers are actually 4-ohm.

If you've got an aftermarket head unit, or otherwise modified, all bets are off.

The rear speakers are wired in parallel and are supposed to sum to a four ohm load. The rear door is a 6-ohm and the rear deck seems to have a resistor in series from the factory - I haven't taken testing equipment to it, so I'm not certain exactly.

I've replaced my four door speakers with four-ohm units, and did locate mounting plates to let me put any common aftermarket tweeter in the dash. I've got the part number listed in an 850 speaker replacement thread. It sounds very good with the 4x40 OE amp in the dash, but the rear door speakers are overwhelmed by the deck speakers when you're sitting in the back.

My plan is to restore impedance balance by installing an aftermarket amp in the trunk to drive the rear deck, so the amp once again sees a 4-ohm impedance. I'll choose the amp to filter out everything above 100Hz, effectively turning the factory rear deck speakers into near-sub woofers. No other cone will ever match the trunk as well as those originals, despite their primitiveness.