Sound cuts in and out at louder volumes

I've troubleshooted this problem to the best of my ability, hopefully one of you guys with more experience has an answer. The problem: On a cold start the system will work fine playing at 24-25 volume on my Alpine deck, for about 10-20 minutes, then the music starts to cut in and out. This last time before the sound started cutting in and out I noticed whenever there was lower/harder bass, the speakers began to make odd popping noises; however, they weren't very distinct sounds so it was hard to tell what it was (and I believe it was only from the passenger side speaker, but again hard to tell). The funny thing is when the system starts cutting out, if I back the volume down to 20 or below everything works fine. As soon as I raise the volume from there it will start cutting out again soon - happens immediately if I raise it to 24 or 25. The info: I'm running an Alpine 9847 deck, two Alpine Type R component speakers up front, a new 2 channel Alpine amp putting 50 watts RMS to each channel, and a newer Optima Redtop battery. I just recently installed everything; amp power and ground wires are 8 gauge and the speaker wires are all 16 gauge. So far I've upgraded the big three to 4 gauge wires, made sure I had a good ground for the amp, and upgraded the power wire and ground from the deck. I set the gain using a test tone with the volume at 27/35 and the gain ended up at a little over halfway on the amp. On the amp the filters are off and bass boost is at 0. The way I wired everything up is through a distribution block. The block is wired straight to the battery with one wire connecting to the amp and the other to the alternator. The voltage display on it reads 12.2-12.5 with car shut off and 14.7-14.9 with car running. I can't think of what else to try to make my system work the way it should, any ideas? (sorry about the long post)

Sounds like you've either got too low an impedance load on your amp, your gain is too high, and/or you need to high-pass those components to keep them from bottoming out.  Try turning on the HP filter on the amp and set it for about 80Hz (do you have a sub?)  Do you have TWO sets of components connected to the amp?  Did you install the components using their supplied passive crossover?  Support the12volt.com

The deck has built in crossover settings and is set at 100hz. I only have one set of components up front (that's it, no subwoofers yet) and passive crossovers are installed correctly with the jumper set at -1.5db for the tweeters. So too low impedance would mean that the amp is not receiving enough voltage to drive the speakers at higher volumes? I will check this with a multimeter; however, I don't think this could be the problem as the wiring is sound.

No, impedance refers to the load of the speakers on your amp.  I think Alpine Type R sets provide a nominal 4-ohms.  So, if you've used the crossovers and you have only one set of speakers connected to each amplifier channel (and assuming your setup is sound with no shorted or defective speaker wires) you should be OK.  This leaves too high gain setting, or defective speakers or amplifier.  Also, if you have the HU crossover set for 100Hz, you are not getting much low bass since you do not have a sub.  Please make sure your bass tone control on your HU is not boosted to try an compensate.  Set it to "0" or no more than +2.Support the12volt.com

Update: I just realized that I had only used one cd the each time this problem happened, a rap cd. I don't have a sub woofer, but when my system was working, those type R components provided a lot of bass for rap even with the HU crossover at 100hz. On the flip side the bass control was set at +3 on the HU. I don't remember if I set the gain with it at +3 at the time or with the EQ settings on the HU flat (I think they were flat). So I just went out to my car, turned the bass eq to 0, and put in a heavy metal cd. Right when I turned up the volume to 24, it cut out once, then worked at 23-24 for the rest of the 25 minutes of driving. At the end of the trip the amp was merely warm. So do you think the problem was that the gain wasn't properly set for the amount of power the speaker required to produce loud and low tones at higher volume? That would mean that the gain simply needs to be turned up or better yet, set correctly for HU EQ settings and the gain being too low would account for music cutting in and out at higher volumes, but not at lower volumes? Also, my components are rated for 70RMS watts and the alpine amp is rated 50RMS watts per channel at 4 ohms - so even if I am more inexperienced than I think I am, will the speakers will hold up to an improperly set when set 'too high?'