Distortion problem in single cab

Hey everyone I have a 2003 Chevy Silverado single cab. I have a 10" SPl dual 4 ohm sub(SPL ELF-10) and a Boss RT 850 mono amp. I am running my sub at 2 ohms. Anyways i had a sealed box that was .97 cu ft and my sub was distorting, so i had sealed box made to the specs on my sub which was a 1.5 cu ft. NOw my sub sounds a great deal better in the bigger box..but when i turn it up fairly loud it starts to distort when my windows are rolled up. When i roll the windows down it sounds better but it still distorts. Can someone tell me what a solution might be to stop the distortion? Thanks David

That amp may be your problem, or the gain is not set properly. I think when you roll the windows down it masks the distortion. Perhaps you are expecting a certain level of volume that simply cannot be achieved by your current setup.

^^^^^^^I agree, the Boss amp is more than likely your main problem. I would have a qualified installer look at the system and adjust the gains for you.