I have 2 10" JBL GTs in a sealed box with 180W RMS going to each in my trunk. I just burned this mp3 to a cd (I have an MP3-CD player in my car) and tested out the subs. The volume setting on the amp is about 80% so it's pretty much at 180W. The volume on my head unit goes from 1-30. I usually play around 15, and that's pretty soft. Well, playing the sub test at 15 made my ears tingle and I couldn't see straight. This is a perfect tool for tuning your amp. If you have a fast connection IM me and I'll send it to you. AIM: Suger007
*still shaking*
Jeff