0Vette Stripes

If the mid is 4 Ohms and the tweeter is also 4 Ohms. I run them parralle to make the amp run in 2 Ohms. So do the speaker right now become 2 Ohm speaker? I know 2 Ohms speakers are easy to get burn then 4 Ohms speaker.
To me, I think the speakers are still 4 Ohms just the amp is running at 2 Ohms.
Please correct me if I am wrong. :cheers:

GTLocke13

This is gonna be tough to explain without some special fonts, so just bear with me. The impedance of each individual driver doesn't change no matter how you wire them, only the impedance seen by the amp changes. Here's how impedances work:

If impedances are wired in series, the total impedance is the sum of all the impedances:

Req = R1 + R2 + R3 + ... + Rn

If impedances are wired in parallel, the total impedance is the inverse of the sum of the inverses of the individual impedances:

Req = ____________1____________
`````````_1_ + _1_ + ... + _1_
````````` R1 `` R2 `````` Rn

If there are series/parallel combinations, you do them one at a time until you're down to a single impedance. So two 4-ohm speakers wired in parallel, then wired in series with another 4-ohm speaker gives a total of six ohms. 4 in parallel with 4 is 2 plus 4 equals 6.

(All the little tick marks in the equation above are just there to hold the spacing)



[Modified by GTLocke13, 2:31 PM 11/5/2002]

92TripleBlack

Most setups with seperates (mids and tweets) are designed to give you a set ohm rating that includes both mid and tweet combined. For example, my boston pros are a 4 ohm combo, not 2 ohm or 8 ohm depending on how you wire them. If used individually, I don't know what the rating for each piece would be. Its just like a coax or triax speaker only mounted in seperate housings. You won't need to worry about this if you are using a passive crossover and single channel from an amp to power them. This is how most seperates are designed to run. Another good reason against setting up your own crossover points and biamping seperates. http://www.mobileaudio.com in the FAQ section has a good write-up on parallel and series wiring that expands on GTLocke13's good summary.

TheWacoKid

If you are using a passive crossover, you don't need to worry about impedance, it will be whatever the individual speaker is(dependant on the frequency). So if you have a 2 ohm woofer and a 4 ohm tweeter, the amp will see 2 ohms when playing in the woofer frequencies and 4 ohms in the tweeter frequencies. So, your mids and lows would be louder if the amp makes more power at 2 ohms rather than 4.

At least I think this is how they work...correct me if I'm wrong.

VetNutJim

You guys are getting too 'technically advanced'!

You're all correct. Ohms Law proves it.
Inductive reactance proves the change in 'dynamic impedance' from low to high frequencies,also.

Way to go guys!! Great advice.

GTLocke13

Its actually a little more complex than that (literally). The impedance of a speaker is complex, which means it has a real and an imaginary part. Resistors have purely real impedances (also known as resistance), while capacitors and inductors have purely imaginary impedances; inductors are positive (i) and caps are negative (-i). The impedance the amp sees is gotten by solving for the complex impedance looking into the circuit. The relative output levels of the speakers are dependent on the crossover components, the specs of the speaker, and the box that the speaker is in.