The components are probably 4-ohm. Just run them straight up to two separate amplifier channels.
For a single sub I prefer a class-d mono amp. Anything from RF will be solid. Try to roughly match RMS... but it really isn't that important if (a) you aren't an idiot with the volume control / gain setting and (b) aren't looking to compete or expect more from your system than is realistic.
Yes, the 2 4ohm vcs will be wired in parallel at 2 ohms.
See https://www.bcae1.com/ for a lot of great information.
Good luck.
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New Project: 2003 Pathfinder
Thanks for the info, I was planning on getting a 850 RMS for the 200-500 RMS sub and just tuen the gain down about 1/3. As for the comps, the amp I was scoping out is rated at double the RMS. Would turning the gain down about half and matching it from there be ok?
You have to have speakers installed, or at least temporarily hooked up, that will take the full power of an amplifier in order to successfully set the amplifier gains. Look at the gain setting procedure; if you use the best street method, it is to listen for the clipped signal while playing a sine wave with a test tone source. If your speakers aren't rated to handle that amount of power for at least a little while, you stand the chance of burning them up before you get the gains set.
So you are left with setting the gains using either an o-scope or a digital multimeter. Not many people have the scopes and are used to using them, so I'm guessing you'd go the meter route. You would have to use Ohm's Law calculations to determine the target voltage output to meet the RMS of your speakers and set the gains that way. This is not a listening test, so you would have your speakers disconnected while doing so.
You can't use a relative position of a gain control as a guide, e.g. turning it to the halfway point. That doesn't tell you anything. You either have to see the wave clip with a scope, listen for a clipped signal, or calculate and read a voltage output. If you are going to use an amplifier that is rated at a higher output than your speakers can handle, you HAVE to go through the proper gain-setting procedures by the book so that you can protect your speakers from being overpowered.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Damn stevdart, my head hurts after reading that but it was very informative. I appreciate all the info. I just want to add one more thing. This is about quality of amps. I was thinking of goign all kenwood for the amps or all alpine. Are Alpines underrated?
I was thinking of these for the comps
Alpine MRP-T220 50x2
Kenwood KAC-7202 150x2 with gain adjusted
And these for the sub
KEnwood Kenwood KAC-8152D
Alpine ALPINE MRP-M350 Monoblock
Thx alot!
Go with less wattage than you need if you either (a) tend to crank the volume knob or (b) don't know how to set gain correctly. This may seem counterintuitive, but if you hard clip a big amp into speaker with relatively low power handling ability, you're in for a broken speaker.
My advice: go with the Alpine for the components. 50w is plenty for those with a proper high pass crossover.
Again, go with the alpine for the subwoofer.
Don't be so worried about power. You need to double the power for a small 3db gain in SPL.
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New Project: 2003 Pathfinder
Well thanks , info helped alot and Im sure it will help others as well.
I decided on a RF amp P3002 for comps and ALpine V12 MRD-M605 for the sub.
RF P3002 75x2 @ 4ohms
Alpine V12 MRD-M605 600x1 @ 2 ohms rated at 12V
Thanks a bunch!