Rainbow 2 Ohm Speakers vs. Zapco amp

[beak81champ]

Another noob question from the slow learner! I am looking at a set of Rainbow CSX 465.20 components which are 160w rms@ 2 Ohms. I already have a Zapco ST-105D BT 5 channel amp which says it will run @ 2 Ohms 4ch x 180w rms + 1 x 350w rms. The speakers will be (4) 6.5" mids (1 in each door of my truck), + 2 tweeters up front. Will this cause a problem for my amp, having the mids and tweeters on 1 channel? Will this take it to 1 Ohm? Should I run the rear door 6.5's off of the HU, and run each front stage speaker off of it's own channel? For now, I will be running passive crossovers.

I am going to purchase another amp to run my subs, as I believe this amp is under powered for the subs I have.

Every time I read something new, I start questioning my choices of equipment. Obviously, I started purchasing backwards. I guess I should have gotten my speakers first, and that would have told me the wattage and ohm load I needed out of the amp(s). I will know the correct way when it's time to upgrade, but for now I guess it's the school of hard knocks (on my wallet)...lol

Thank you for any and all information and opinions, as always!!! You guys are my mentals (I mean mentors!!!)

[Hic]

You can measure the ohms at the crossover [ where you will attach the power wire ] with a digital multi meter set to the Omega sign or horseshoe looking type symbol.

[beak81champ]

So, if it reads under 2 Ohms, then I need to switch each speaker to it's own channel?

[papacueball]

DC resistance will read lower than the quoted nominal impedance. Don't let that freak you out. Also, the woofer and tweeter don't play in the same range when connected to the crossover. Probably not when wired straight to the amp, either. Impedance of a speaker will change depending on the frequency being played. You still need a highpass filter for the tweeters, though. As long as you connect everything properly, you should have no problem running what you have. Some will argue against running rear speakers in an SQ system.

edit: I was checking out those speakers. Looks like you connect two 4ohm woofers and a tweeter (probably also 4 ohm, i bet) to each crossover. How did you plan to connect them to the amp? If you connect one woofer and tweeter to each of the front channels through the crossovers, and one woofer to each of the rear channels, you will get a 4ohm load on all channels.

[beak81champ]

I'm starting to rethink the rear speakers myself. I think I can get a little better set of fronts instead of worrying about the people in the back seat twice a year!

[Hic]

hope it works out very well !!

[beak81champ]

Thanks Hic! I will eventually make up my mind, then I'll need a bunch more advice!!! Thanks for everything so far!