Hey everyone. I have a 72 Cutlass currently with the stock radio in it's natural position and an aftermarket discreetly installed. 2 kick panel speakers and 2 rear 6x9 speakers all 4 ohm. I don't listen to that much music while driving so I am removing the aftermarket however I would like to utilize the rear 6x9's and front kick panel speakers instead of the single center dash speaker. The AM/FM radio is equipped with the blue rear speaker wire. I have seen multiple threads about wiring the 4 ohm speakers in series to allow them to operate with the factory radio. Would anyone be so kind to explain this process so that I do it properly? As always I appreciate all the help!

Mike

 

It's really not that big of a deal with a 4 channel output. A 2 channel (OEM front and rear centers) is slightly different. Yes, you can wire the fronts and rears in series. Sonically, that's horrible because then front becomes left and rear becomes right or some other abortion of stereo sound.
To wire 2 speakers in series: pick one positive, and the negative off the other, then connect the remaining positive and negative together. Ideally, if you tap a 9v battery to the leads, the cones will move forward. This means the speakers are operating in their optimal range.
It's a whole rabbit hole, but if you just want sounds, it doesn't really matter. For all i know, the factory front and rear outputs are mono, with no stereo separation.

 

Pretty straightforward


Power source is radio load 1 and load 2 are the 4 ohm speakers. Just pay attention to the wiring, in this example the - from the power source would have gone to the left side of load 2 originally so when adding the second load (load 1) the only new wire is the one you add between load 1 and load 2 and then attach the - from the power source (radio) to the left side of load 1. Or the whole descrition could be reveresed with reference to load 1 and load 2. You would also have to splice in additional wire from the original - wire from your battery since it would not be long enough to reach to the back speaker. If you use colored wire that works, or some people use the brown or white or black wire for wiring household lamps that is two conductors molded to one and just split it apart but that makes it harder to keep track of which wire is which. Just be sure to pay attention to which wire is which.

 

On behalf of wiring enthusiasts everywhere- for the love of God, do not use household electrical materials in your car. These include, but not limited to, zip cord, wire nuts, white zip ties (non UV rated), masking tape instead of electrical tape, etc.
Also, Scotchloks are the devil's work.

 

Thank you everyone for the help. With the stock radio only having the blue lead to the rear I just wanted to make certain I was doing the right thing. I plan on getting this all wired up this weekend.

 

This made me laugh! I love when I see household materials in a car!

 

I understand the sentiment voiced above and agree, just slipped into remembering my younger days before I knew better and mentioned the zip cord since I did use it way back when. I should have recommended using correct wire and connectors.

 

Any multi-strand, insulated wire is appropriate for use as speaker wire. EVEN ZIP CORD! The only difference between speaker wire and zip cord is the price and the color of the insulation. I installed thousands of feet of "zip cord" as speaker wire back in the day.

Since you are using the factory radio, the blue wire in the rear will attach to the positive (+) lead of the first rear speaker. The negative (-) of that speaker is then connected to the pos (+) of the second speaker. The neg (-) of the second speaker will be attached to the body of the vehicle to complete the circuit. This will create an 8 ohm load for the factory radio. The same can be done for the front. This WILL NOT provide stereo sound! Just front and rear monaural (mono) sound.

 

"Stereo" sound has been mentioned a few times in this thread. I just thought I would mention that at least through 1972, Oldsmobile used a front and back speaker for the 2 stereo channels in their stereo radios and 8-track players rather than a left and right speaker. This is interesting because Chevrolet started using 4 speaker stereo systems in 1965 and 4 speaker 8-track systems in 1967.

 

Thank you all for the help. Got it all wired up and boy does that mono sound take me back a few years! Kinda crazy but this is exactly what I was looking for.

 

Resistance in series adds. Resistance in parallel divides.The above diagram is correct for series but you end up with a 16 ohm load on your amp. It will suffer from low volume and the sound quality will suffer. Eventually the amp section of your radio will fail. The amp is designed to drive approximately 8-10 ohms. to get to that number you would need to wire 2 4ohm speakers in series or 2 16 ohm speakers in parallel. I've never seen a 16 ohm speaker but there are plenty of 4 ohm versions out there, Good luck.

 

The original poster stated that his speakers are all 4 ohm.