Is this speaker okay?

[AnthonyG]

Hello All

I'm simply trying to replace the subwoofer speaker in my stock JBL system in a 1992 Ford Explorer.

The problem is that no one seems to know what the ohm rating is for the stcok amp (it's not even clear from the vehicle shop manual).

Crutchfield identified a 4 ohm speaker that will fit in the opening (6.75"). The salesperson and tech there both tell me that there shouldn't be any risk of damaging the amp connecting this. The Ford shop manual sales the speakers vary from 6 to 8 ohms, though I think it's talking about the door speakers. The section on the premium sound system says nothing out ohms or watts.

I'm not blasting the volume on this thing normally, though I don't know if that makes a difference. No speakers will be in series. The purchased speaker is a JL Audio C5-650cw 6-3/4" Component Woofer. I know that's overkill, though it gives me the opinion of upgrading the amp if I want at some point (This car is vritually showroom condition with only about 100,000 miles).

Any thoughts? Would you install it?

Thanks.

Anthony Giorgianni

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[>>SQL<< 10+ year member]

I am sure it would be fine.

The only way of hurting the stock amp is by running a speaker with a lower than stock impedance.

I doubt that 4 ohms would be lower than the amp was designed for.

 

[Fiendstolemyamp 10+ year member]

Why don't you take out the factory sub & see what it's coil reads with a DMM (digital multi-meter)? Then you'll know.

 

[AnthonyG]

Thanks Fiend....

I tried that:

1) I keep reading varying advice on wehther the number from a mulitmeter is accurate. (though some say it's okay, though may be a bit low?)

2) Every time I try it, the number keeps changing. I put the leads on the speaker tabs. Sometimes it read 2.5, sometimes 5, sometimes 1. Sometimes the needle keeps jumping around, especially if I put the leads on the wires coming off the tabs. I'm not sure what this means. Am I doing somthing wrong?

AnthonyG

 

[Fiendstolemyamp 10+ year member]

You just want to try to read the coil on the driver(sub), not any wires coming from the amp. A result from 1.5-2.5ish would mean it's a 2 ohm impedance (as you are measuring DC resistance, not impedance) 3.4-4.5 ish would would be 4 ohm impedance. Just do the best you can. I'd say the JL driver would prop work regardless, it 4 ohms right?

 

[AnthonyG]

Thanks again Fiend

Yes 4 ohm speakers. And I am reading off the speaker, not the amp. Just got 8. Then I tried it again and got five. Bfore that 2. Again, this is readling off the speaker connectors or the wires off the connectors that go to the coil. The speaker makes a slightly crackling noise when I do this.

 

[hispls 5,000+ posts]

You're using an old school analog ohm-meter aren't you?

The speaker is DISCONNECTED from the car's wiring when you measure impedence? If you're pushing on the cone, have it in the wind or in a noisy area the reading will fluctuate also.

1000 to 1 against you hurting anyting running 4 ohm. You will very probably get LESS output if anything than the factory.

 

[AnthonyG]

Well, I don't know about the multimeter. I just installed the speaker, and it's working. Sounds pretty bassy. Don't know how it compares to what was in there before. We'll see what happens. Thanks everybody!

Anthony Giorgianni