Ohms are your load resistance.

Speakers and Amps need to be matched for optimal performance.

Using the formula R1+R2+....Rn for series circuits and (R1*R2) / (R1+R2) for parallel circuits We see that:

In series: (2) 4 ohm speakers would yield 8 ohms resistance. Series in this instance is

Amp + ---- +speaker R1 - ------ +speaker R2 - ----- \ In a series circuit the negative lead of the first speaker

- -----------------------------------------------------/ connects to the positive of the second.

Parallel gives us 4 ohms of resistance.

+/----------- + speaker R1 - ---\ In a parallel circuit both the positives of the speakers would be connected

AMP -\\---------------------------------/ to the same positive connection on the amp. The negatives follow the same pattern.

\\--------- + speaker R2 - ---\

\-------------------------------/

Understanding this, allows for some flexibility in designing the system.

I.G. We have been given a 4 ohm amp, but we already have a pair of 2 ohm speakers, we could run them in series to match the amps load requirements.

By the same idea if the cases were reversed (2 ohm amp and 4 ohm speakers) we could run them in parallel to match the load.

If the load is not correct, amp and /or speakers can be damaged.

This is by no means a 'be all end all' post. In designing the circuit, you have to consider things like: power out put of the amp (both nominal and peak), nominal and peak power requirements of the speakers and a host of other requirements.

I know the post is late for this question and the art work is bad, but may be it'll help someone.

Lee

Carpe Diem - Seize the Moment, Enjoy the Day!