speakers

Great post George! Lots of good info on speakers and how they relate to old radios.

amxdreamer wrote: Steve, I purchased and aftermarket 4x10 for my AMX and covered it with grill cloth like the originals were done. You can't tell the difference from above yet the sound is "decent". This is from someone that competed in IASCA (car audio competitions) at a fairly high level (world finals twice - 7th and 9th). There are a few members here that work in the audio field or own shops, hopefully they can also provide some feedback. The speaker I installed was a 4ohm model so the factory AM/FM will actually be working a little less to power it. Plenty of volume but I barely turn the stereo on, I prefer to hear the music the car makes :) As you can see in this picture, I used the original wiring harness and installed foam etc. as per the factory and every bracket, screw etc was restored.

DoughertyAMX wrote: amxdreamer wrote: Steve, I purchased and aftermarket 4x10 for my AMX and covered it with grill cloth like the originals were done. You can't tell the difference from above yet the sound is "decent". This is from someone that competed in IASCA (car audio competitions) at a fairly high level (world finals twice - 7th and 9th). There are a few members here that work in the audio field or own shops, hopefully they can also provide some feedback. The speaker I installed was a 4ohm model so the factory AM/FM will actually be working a little less to power it. Plenty of volume but I barely turn the stereo on, I prefer to hear the music the car makes :) As you can see in this picture, I used the original wiring harness and installed foam etc. as per the factory and every bracket, screw etc was restored. Where can you get the grill cloth like you used, and is that just adhesive backed foam you used on top of the speaker mount to go between it and the dash?

If you connected the dual voice coils in series then the resistance (impedance) would be additive. If connected in parallel then the rating would be halved.
Most likely the voice coils of the dual voice coil speaker are rated 8 ohms. If so, then a series connection would yield a 16 ohm load to the radio which would result is the speaker receiving less power from the radio though this would cause no harm to the radio itself. ( The higher the resistance of the speaker the LESS of a load it presents to the radio's amplifier ). You may not have enough volume however.

On the other hand if each voice coil of the dual voice coil speaker is rated at 4 ohms then connecting them in parallel would yield an effective load of 2 ohms and this could very well be a problem for the radio In this case you'd want to series connect the coils together. Connect one conductor of the speaker feed wire pair to the negative terminal of the first voice coil. Then jump the positive terminal of that coil over to the negative terminal of the second voice coil. Connect the positive terminal of the second coil to the remaining conductor of the radio's speaker feed wire.

Assuming the car radio is a mono, single speaker feed, radio, then it doesn't matter which wire goes to the negative terminal and which goes to the positive terminal when you're series connecting the dual voice coils of a single speaker together. It is important however that the positive terminal of the first coil is connected to the negative terminal of the second coil. In a parallel connection negative terminals of both coils are jumped together and positive terminals are jumped together.

When doing a stereo, or multi speaker system, then the polarity and connections must remain the uniform between all the speakers in the system.

Edited by george w - Nov/25/2020 at 10:25am

Just getting ready to put new speakers in my 73 javelin. I have the parts manual and it is showing different part number for the speakers between 1973 and 1974. I also have the 1973 manual for the amc radio system for multiplex radios and they are saying 4 ohm speakers for front and rear but like I said 1974 parts book is showing a different part number for the speakers.