i'm confused about caps and coils

When I was a rookie I was bound and determined to get more out of the amplifier than it was designed to deliver.  I, too, searched for Lpads and was lucky (I guess) to find a couple at a now defunct web house, and it wasn't easy, as you have seen, finding the 4 ohm variety.  I hooked up the rear speakers that way so I could turn them down lower than the fronts.

Well it wasn't long after that I got the amplifiers I needed for two component sets, two rear coaxials and one sub...just a four channel and a mono amp.  Now I don't need those Lpads but they're installed and staying in that car for the last four or so years, and they are still being used but not needed, as I could have used the deck's attenuation for the rears at that point.  It was a matter of me wasting money for something I should have done something differently about.  But I always look on the brighter side and consider it a learning experience ;)

You said you are hooking up a set of components and a coaxial to each channel.

"I'm hooking up to a 75 Watt RMS per channel amp.  I've got a set of components and one 4x6 speaker running off each channel."

It looks like you are trying to get too much out of that amplifier.  One channel should power one component set or one coaxial, not both.  Advice is to get the amplifiers you need to do the job right.  You'll be upgrading to what you should have had to begin with sooner than later.  Unless, of course, you are in it for the learning experience.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

I didn't mean that the amplifier would be overworked.  I meant that you have to go to extraordinary measures because there aren't enough channels for the speakers you want to power.  But you could use resistors and if one doesn't attenuate the speaker enough, add another in series.

Use the tools found to the left in the blue help area, "parallel and series" resistance calcs to help with configuring resistors to give you the attenuation you want.

I want approx a 50% drop in volume and and cut everything below approx 500 Hz.  So I guess I'm looking at a 4 ohm resistor on each channel.  Are these just the standard resistor?  One you would find on a circuit board?  I would add them in series in order to increase resistance correct?  This is just spliced in on the positive line? The amp would see an 8 Ohm load form the dash speakers?  Would this effect the 4 ohm components in terms of volume output or do they remain unchanged?

Thanks for your help