Lets say a birth sheet on a kicker 900.4 says 1120 watts, and 3 channels will be used. 2 on 2 polk 6 1/2 components 100w rms each, and 1 channel bridge @ 4 ohms on 2 kicker comp vt 12's which are 400w rms each. What amount of wattage will the speakers be getting and the amount the subs will be getting?
Do not at all quote me on this but, I would say that your speakers would be receiving around 140 watts and your subs would be receiving around 280 watts each. I don't know if this is correct but this is how I came up with these numbers. I checked the specs. for the sx900.4 and noticed that the watt output double for every drop in ohm load so, I took your 1120 and figured that was 1120x2 @ 4ohms bridged. I then divided 1120 by 2 to get 560 bridged per channel then divided that by 2 to get 280 per channel at 2 ohm. After that, I just took half the 280 since both speakers will present a 4 ohm load at there respected channel to get 140 a piece. The sub channel as we will call it, I just took half the 560 to give each sub around 280 watts since that channel will be bridged at a 4 ohm load.
Now, I have no clue whether or not this is correct I'm just throwing an educational guess out there. If anyone actually knows if this is somewhere close to being correct let me know. If it is way off the mark let me know as well, I'm always up to learning new things and being educated!
Look at what your amp is rated at doing. It should say how much per channel and how much bridged at a 4 ohm load. Remember those ratings are at a constant 14.4 volts, drops in voltage will drop the rms produced some. Thats where the big 3 comes in to help.
SLAB, the amount of power each speaker will be getting will fluctuate continuously, and by large amounts. There is no way to know how much actual power a speaker gets at any moment without the use of some specialized equipment. power varies based on input voltage, current draw, amp efficiency, impedance rise, cabin gain, transfer function, the volume level of the source unit, the frequency being produced at that given moment, the source material itself, the resonant frequency of the vehicle cabin, and any number of other factors.
the birth sheet numbers are mostly meaningless, since those numbers are an anechoic measurement taken on a test bench, at full output to a resistive dummy load with a full spectrum white noise input signal at -0dB reference level, with a regulated high current switching AC to DC power supply. You'll never, ever see that output in a car. Not ever.