[mustang17]

just recently my system has lost probablly 50% of its bass. ive oonly had the system for about 3 months. I have a jensen flip up hu , kicker speakers, kicker 400.1 amp and 2 10s in a box. i think some of my speakers are blown but when i turn the bass all the way down on the headunit it still sounds bad , i dont know any suggestions?

[TurboLX]

jensen isnt that great

[TheUNZippee!]

+1. Jensen is not known for making quality stuff, not a shot at you here, just telling it like it is.
That being said, if it at one time sounded good, and now sounds bad, there is a problem. The first thing to do is go through the entire system and check for solid connections. That includes grounds You would be surprised at how many problems are caused by a bad or inadequate ground. The amp should be grounded directly to the chassis of the car, fairly close to the amplifier. Do not run your ground all the way back to the battery, or you will pick up a shitpile of noise.
After ensuring all your connections are good, start a process of elimination. Shut everything down but the subs, and turn them up. You can do this by pulling the rca's or speaker wires to the rest of the system at the amp. Then pull the subs out of the system, and put the rest of the speakers back in the loop. Use your balance & fader controls, and a good level of volume to go through each speaker, to see if you can find any bad one(s). If you find a bad speaker or two, problem solved, replace said speakers. If all the speakers sound like crap still, and all your connections & grounds are good, chances are you have a fragged head unit or amplifier.