I posted this question in the original DMM setting thread, but didn't get any replies, so I thought I would start a new thread about it.

Basically my question is this, how does the resistance calculation work for components?

The amp is driving more than one speaker per channel, which in my case are different resistances, so I don't know what to plug into the equation. My mids are rated at 4 ohms, but the tweeters are 8 ohms. I also have a set of imaging tweeters wired in parallel with the front components. So what number should I use for resistance when determining the voltage?

Thanks in advance for the help and sorry for sort of cross-posting.

Do you have a passive crossover after the amp for the components?

Where did you tie into the wiring to run the imaging tweeters in parallel? Before the crossover, or after? If after, on the woofer or tweeter wiring?

If you didn't have the imaging tweeters, the answer would be simple. You would calculate for whatever the component set is rated for...usually 4 ohm, although some 2 ohm component sets are availabe.

Yeah, the components are wired after a passive crossover which is connected directly to the amp. I am not sure about how the imaging tweeters are wired, since a shop did the initial wiring.

I guess I'll have to open it up and see where the crossover for the imaging tweeter is connected.

Suppose I didn't have the imaging tweeters, just the components (4 ohm mid, 8 ohm tweeter) connected to the amp through a passive crossover. How would the resistance be calculated?

Thanks for your help.

If you had only the component set, you would calculate the voltage for whatever impedence the component set is rated for. The crossover network will determine the impedence to the amp. What brand/model components do you have? We can look them up to verify, but they are most likely a 4 ohm component set.

I would bet that your imaging tweeters are being powered by your head unit. ...at least, that's probably the best way to do it with your setup.

I personally have no experience with this kind of problem. However, the logical answer to me is to use the 4 ohm resistance. The resistance of the tweeter is really not that important as it needs barely any power to get going. also, if you plug any number higher than 4 ohms into the equation you will get a pretty high number, which I doubt you will reach on your amp.