alpine pdx 8 ohm rating

I edited my last post after you quoted me.  Read it again.

ok yeah, thats still just fine. 80 - 90 watts is still right in the happy zone for my tweeters, even 100 watts is ok, just not 150.

What crossover frequency are you using for the tweeters?  They are unlikely to use more than 15 watts or so depending on the Xover frequency.Support the12volt.com

im not sure on what frequency what i will eventually settle on but i will be using a cache 3-way active crossover before the amp which is fully adjustable. the set of components im using are diamond D9's or Hex pro as they are now called. mine are actual D9's from before they changed the name. first im going to try to figure out what frequency they get crossed over at from the crossover that came with the set and ill start with that and i might be happy. my best guess is that it'll be in the range or 2800hz to 3500hz. im doing this mainly to simplify my setup a bit because the passive crossovers are huge and i would rather not have to use them if i dont have to. im confused with your statement about them only using 15 watts or so. can you explain a little bit? i understand that the amp makes more or less power depending on the frequency being played but im under the impression that the amount of power that the tweeter uses is dependent on the resistance it presents to the amp at any given frequency. the tweeters are rated in the owners manual for 75 watts. i know this is not the rms at all frequencies within its range but im still confused.

The owner's manual rating is program power, meaning when used with their crossover.  As far as how much power a tweet will actually need, that's dependent on the crossover point and on your volume control.  At normal loud listening levels a woofer might be using 100 watts, a midrange 45-50 watts and a tweeter 10-12 watts.  The higher the crossover point the less power that's required to play music.

Your owner's manual lists the fs of your tweeter as 850 Hz, which is quite good, and means you can safely cross it as low as 1700Hz (2X fs) with an 18 db/oct or steeper crossover.

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ok thats interesting, maybe i should go with the pdx-f4 just to air on the side of caution. i really really want to avoid having to find a place to put both of those humongous crossovers. i have an extended cab ford ranger and im already short on places to put things.