21boy

Well the two original speakers in my 74 are shot so I got 2 4 ohm ones. Will these be safe to use with the stock stereo? The stock speakers where 10 ohm.

wer2xu

you can get delco 10ohm speakers from your local GM parts guy...they bolt right in.

Alan 71

Hi 21B,
Jerry Rudbeck the radio repair man told me for the well being of your original radio you need to continue using 10 olm speakers.
Regards,
Alan

7T1vette

You can hook up 4 ohm speakers and they will function. However, there will be a sizeable impedance mismatch between the speakers and the radio output section. If you turn up your radio very high, it could burn the output section up completely (literally...burn it up) and will likely have distorted sound quality. You would do much better to buy some 8 ohm speakers. You won't burn up the amp with that small amount of mismatch. In fact my Delco unit is hooked up to two 4 ohm speakers (in series) which equals 8 ohm total impedance. No problems with mine.

If you already have the new speakers installed in the dash, your best solution would be to also install some 4 ohm speakers behind the lower kickpanels and wire them in series with the dash speakers (on each side).

21boy

Can you put 4 speakers on the stock radio even though stock was 2?

7T1vette

You can put as many speakers on as the unit will power...as long as the total impedance of the group is matched with the head unit. The Delco head unit puts out about 16 watts of power. Since it is not a powerful unit, you want to select 'efficient' speakers...ones that have a low power rating. If you choose speakers that can handle 100 watts of output, then most of the energy going to the speaker will be eaten up by the larger magnet [which is needed to handle the 100 watts]. Speakers that are rated at 20-30 watts are what you need. Just hook two 4-ohm speakers together in series on each side so that their combined impedance is 8 ohms.

{Series connection is achieved by connecting the green speaker lead to the (+) terminal [or terminal identified by a paint dot] of the first speaker, then connecting the (-) terminal on that speaker to the (+) terminal of the second speaker. Finally, the (-) terminal on the second speaker is connected to the black speaker wire to complete the circuit.}

21boy

Oh I see. I'll do that then thank you.

Lon Wayne

You could also use some resistors in line from Radio Shack a lot cheaper than new speakers.

7T1vette

The resistors would allow for the impedance match...but you would lose more than half of your radio's output power to them.

21boy

Ok I got some 8 ohm I can circuit in with the 4's. My radio gets some FM when it's on AM and FM doesn't pick up any channels at all. What happened here? Both original speakers are also shot some how..

7T1vette

Sounds like you have radio head unit problems. You might want to give a call to the radio guy that Alan71 provided.

CCrane65

I don't think I would put 8 ohm and 4 ohm speakers in series. Two 4 ohms speakers in series or just one 8 ohm speaker per side would be better. Too much resistance can make the wires hot.

I'm guessing you didn't pay too much for your 4x6 4 ohm speakers. I think my Pioneers cost me about $30.00 but I pulled them and replaced them with 10 ohm replacement speakers from one of the major Corvette vendors. I think they cost me about $50.00.

cc

7T1vette

Actually, too much resistance (4 ohm + 8 ohm = 12 ohms) will merely cut the volume output of the radio amplifier; it will pull fewer amps from the unit than it if had the 'required' 10 ohm speaker match. However, the 4 ohm speaker will be at twice the volume level as the 8 ohm speaker...and I think you want the most power to go to the lower [kickpanel] speaker, as it needs to provide the bass content of those two speakers (4"x6" speaker is mid-range/tweeter design...very little bass comes through it). The combination you have will work...but not well.

Alan 71

Hi Charley,
You know a bit about radios TOO.
I had no idea. Thanks for some useful instruction.
Regards,
Alan

21boy

Hmm. I really want a new radio that has modern listening capabilities and that the 2 4 ohms would work on, but is there even a way of putting a modern radio in without some major cutting up of my counsel? Like putting the faceplate over the old whole and the main body of the radio somewhere else?

7T1vette

Many of the Corvette parts suppliers sell gauge cluster plates made for DIN radio mounting. Other places sell radios that look like Delco units, but have modern guts; they will fit in a stock cluster plate. It all depends on what you want and how much you want to pay.