Can I get away with doing this? I finally changed my car from 6v positive ground to 12v neg. ground. I want to run a decent radio and still try to use the stock speaker in my dash. Will the speaker work on 12 volts? Or should I just gut it and get a new speaker?
Speakers don't operate off of battery power they operate off of a signal/power sent by the radio. I don't know what an old radio sends to the speaker but I'm willing to bet that a speaker that is that old won't hold up anyway even if it can handle the power.
The speaker doesn't care about voltage. The bigger concern is dealing with running just one speaker off a stereo, and maybe dealing with a speaker that might have one side connected to ground, but you can get around that stuff.
Old speaker might take a watt or two of power! New stereos are at least 10 watts per channel. Get ready to destroy the cone on it! Just change out the speaker to a new one.
It's not a big deal to put a modern 6x9 in the dash, and there are even aftermarkets now that play the left and right inputs in one speaker made for the middle. Even one 6x9 will probably sound better than the original, even if you get it to play.
What Automotive Stud is reffering to is a dual coil speaker. Go to a reputable speaker audio store with the model of radio you have and the old speaker and ask for a dual coil speaker the same size.
6V radio, that had to be an old tube amp mono radio, the speaker impedence was probably pretty high........hope you didn't pitch the radio. New auto amplifiers got to put out high voltage for higher watts (much higher then 12V), because speakers are (normal 4 or 8 ohms) All about ohms law.. You probably need to get a bracket and mount 2 smaller full range speakers side by side to fit the hole (dual coil speakers are generally woofers) or start chopping holes elsewhere....... boooooob
Tube radios prior to about 58 or so had an audio output tube and output transformer. The transformer output was usually matched to 8 ohm speakers. After 57 or so, the tube type radios reduced the tubes plate voltage to 12 volts and used a power transistor (DS501 in GM radios) which also matched up to 8 ohm speakers. One problem with the radios using DS501 transistors were that the output stage was configured as a CLASS A amplifier, which is a current hog, and can run your car battery down quick without the engine running and the key set in ACC.
If it's similar to my 53 Chrysler, and I believe it is, it'll be a 6 x 9 size 4 ohm speaker. The tube Chrysler radios used a 4 ohm speaker. So... about any modern 4 ohm 6 x 9 speaker will work. Take the chassis off the bracket and reuse the bracket to hold the speaker.. or you could reuse that speaker for that matter, but I don't know as you'll be happy.
Here's what I have in the Chrysler. I got a deal on a Retrosound dual voice coil speaker and was going to use that with a modern stereo, but I think I'm going to use the tube radio after all. The little heat sink is for the 6 volt reducer for the wipers.