Audio Systems: Car audio, watts rms, subwoofer amp

Question
I have a a alpine MRX-F30 - 4-Channel Amplifier running 2 6 1/2 type r speakers in the front along with 2 type r 6*9 speakers in the back i want to bridge them. I don't know if that will harm the speakers but from my understanding its getting 50 watts rms to all four now but the speakers are rated for 100 watts rms and i think when bridged the amp would put out 150 watts rms to each speaker so what would you recommend. i would like them at there full potential but at the same time i don't want to ruin them ether. I would like to know what to set the crossover and gains at when bridged. plus it has at filter setting which i can choose the off or hp or lp setting.

Answer
To bridge the amp for more power it becomes a stereo unit.  Therefore, you will need an additional amplifier to run the other two speakers.  Bridging requires throwing a switch which reverses the phase on one channel; the speaker is then connected between the + connections of the two channels.  Sounds like it will not do what you expected.

Further, doubling the power is only 3db in audio power terms.  The sound is not doubled because sound pressure is logarithmic and it takes about 2 db difference before the human ear realizes a change in level.  Therefore, 3db increase is just a little over the when you hear a difference.  In order to get a substantial audio increase in level you must go at least 3 or 4 times the power level.  And, in doing so you often will blow out the speakers which now requires replacing the speakers with much higher power ratings.

I think you should stay where you are at unless you are prepared to make a substantial upgrade of the system.

PS: I was confused with your question about the crossover setting; that is for a subwoofer setting but you did not mention having a subwoofer amp and speaker????  Without a subwoofer or a bi-amping system the high-pass and low-pass are not used.  If you are biamping then you need separate tweeters and 4 amps for the front and 4 amps for the back - if you are bi-amping the back ones too.  If this is confusing to you, let me know further with a followup question.