Ohms question

[TexasLS1]

I understand what Ohms are, but don't understand how they work with speakers. How do 2- and 4-Ohm speakers differ? Does the higher resistance just allow a speaker to use more power? I don't really understand what physically occurs causing the speaker to work.

[thearborbarber]

Ohm is also the measurement of impedance which is ho speakers are measured.

http://en.wikipedia.org/wiki/Impedance

http://en.wikipedia.org/wiki/Electrical_impedance

http://en.wikipedia.org/wiki/Impedance_matching

[Bearcat]

In AC circuits or signal ohms is measured in impedence

One can actually shunt a capacitor across the speaker leads in order to change the impedence. This will change the frequency band of the speaker
or low and high tone... Bass, midrange or treble.

Ohm in speakers is refered to as impedence.

This is the formula for impedence.
Z = sqrt( (R^2) + (X^2) )


This is the formula for capacitive reactance.
1
XC = --------
2*pi*f*C

You can transpose the formula to figure out your frequency.
1
F= --------
2*pi*XC*C

[01NBMSS]

All you need to know for a basic understanding of ohms is ohm's law:

V=IR

V-voltage in volts
I-current in amps
R-resistance in ohms

You dont need to worry about complicated impedence equations. Assuming a very simplistic system, just know your car runs on a 12V DC system. This means voltage is constant. Resistance of speakers are typically 2 or 4 ohm speakers.

P=VI

P-power in watts
V-voltage
I current

Now, comparing 2 ohm vs. 4ohm speakers and referring to ohm's law, 2ohm speakers at constant voltage receive twice as much current (essentially resistance in the wiring, etc not taken into account) therefore receieving twice as much power. This is why amps specify different amounts of power for different ohm speakers.