Now I have a Kenwood head unit, 4 Kenwood 5.25 speakers, 2 channel Rockford 900 watt amp and an Alpine type R 12" sub. But I'm not satisfied with the sound quality when turned up. I listen to a lot of metal and it just gets nasty sounding.

What should I do?

 

Do you have all the speakers run off of the same amp?

 

They're all running through the head unit.

 

Well if the amp is too much for the sub then turn the amp down a bit. And turn the bass down to your speakers. Little speakers don't like a ton of bass. My recommendation would be to get a small 4 channel amp and run the speakers off of that and set it to only push mids and highs. Next I would get a sealed box for the 12" and adjust the amp accordingly. I had a 12" alpine and all I listen to is metal. The sealed box made it much punchier and let it react quicker. A 900w rockford is overkill for a alpine type r