Let’s Talk Speaker Impedance!

[KP Texan]

The fronts are actually 4 ohm and the rears are 8 ohm. I checked these when I hooked up a 5-channel amp because I wasn’t sure what the impedance the rears were since there are 4.

Anyways you’re fine installing your aftermarket hu.

How did you measure the impedance of the circuit?

 

[dangitzin]

I used my multimeter. But before that I ran wires from the dash to my amp’s location(under driver seat). I wired the wires at the dash to a harness that connects to the stock harness and measured at the other end. You can also measure at the stock harness itself as long as you know which wires they are.

 

[KP Texan]

I used my multimeter. But before that I ran wires from the dash to my amp’s location(under driver seat). I wired the wires at the dash to a harness that connects to the stock harness and measured at the other end. You can also measure at the stock harness itself as long as you know which wires they are.

I’m not too sure this will work, at least with the stock speakers. There is a capacitor in series with the dash speaker to protect it from lower frequencies. As the multimeter applies voltage to take a resistance reading, it will charge that capacitor which will cause the capacitor’s resistance to approach infinity - this effectively removes that speaker from the circuit. Since the door speaker does not have a capacitor, I believe you may have been just reading the 4 ohms through that. Once the circuit is running under AC from the amp, it behaves much differently though and should be closer to 2ohms impedance.

 

[Smitty19TRD]

This is correct. The impedance is 2 ohms. Impedance does go up as you get away from the resonant frequency. In theory, if you crossover the speaker high enough you can run the speakers on a 4 ohm stable amp if you keep it at reasonable limits.

 

[dangitzin]

I’m not too sure this will work, at least with the stock speakers. There is a capacitor in series with the dash speaker to protect it from lower frequencies. As the multimeter applies voltage to take a resistance reading, it will charge that capacitor which will cause the capacitor’s resistance to approach infinity - this effectively removes that speaker from the circuit. Since the door speaker does not have a capacitor, I believe you may have been just reading the 4 ohms through that. Once the circuit is running under AC from the amp, it behaves much differently though and should be closer to 2ohms impedance.

Oh wow didn't know all that. I just went about wiring my stuff like I usually do. Thanks for this. Where can I get more info on this? So I don't end up blowing speakers when I decide to upgrade again.

 

[KP Texan]

Oh wow didn't know all that. I just went about wiring my stuff like I usually do. Thanks for this. Where can I get more info on this? So I don't end up blowing speakers when I decide to upgrade again.

It's a very easy mistake to make since the 4Runner speaker wiring is a bit interesting (especially mine with the party mode button). In fact, if didn't have access to the wiring diagrams and also read through the thread on here about front speaker replacement, I could've easily done the same thing!