Thank's for the explanation, i feel a lot of better now. Actually my current project is build a bass guitar cabinet system. Since I already have a pair of Blaupunkt Velocity VCS1200 woofer,(the response is good till 500Hz, dual 4 ohm voice coil, with 250 watts/voice coil) from my previous car, plus a Carvin DCM2000 power amp, I decide to use it.

And want to order some hifi mid and tweeter, currently my choice are:
2pcs Peerless 850518 4 ohm, 150 watts mid (will run in parrarrel)
1pc Vifa MG27TG39-04 4ohm, 140 watts tweeter.

I will use them for a 3 way system with passive x-over, (consist of one woofer, two mid, and one tweeter) that will drive with one channel of power amp, and an extended bass (one woofer) cab, also use a passive x-over, that will drive with the another channel of my amp.

I didn't run 2 of my woofer in parrarrel, my power amp lowest allowable impedance is 2 ohm stereo and 4 ohm bridged. Thank's to remind me about the 1 ohm load.

Maybe this system is not ideal, but I just want to use the equipment that I already have. By the way, I lived in INDONESIA, and since I must buy the parts from USA, I need to make sure that my choice is right. I didn't want to return the wrong parts, the shipping cost is very expensive.

Thank's

Regards,
Gabriel Temmy

PS: I see in this message board that You often experimenting with pro loudspeaker. Have you ever try Selenium woofer or subwoofer? I already build a system using 2 Eminence Delta 15 and a Selenium horn each side for my band studio, and the result is really good. I really like Selenium horn base on their price vs performance, but didn't know about their woofer/subwoofer.