Guitar amp sounds worse than normal?

Man, how do you guys not know this stuff? You should never, ever, under any circumstances try to play a guitar through a bass amp or a bass through a guitar amp. It's just physics, you know? The bass strings vibrate at a much lower hertz rate then a guitar. Why do you think they make bass amps and guitar amps? If it did not matter, you'd think they would just make a one amp plays all sounds amp, you know? I don't know if your speaker is damaged or if the circuitry in your amplifier is messed up but, if I were you I would take it to a professional and get it diagnosed. I play both the bass and guitar and also the keyboard. I wanted one amp that I could play all three instruments through that would sound truly awesome for each instrument. After researching it for months, I finally purchased a pair of JBL JRX115 2-way speaker cabinets and on the advise of JBL, paired those speakers with a QSC GX5 500 watts per channel stereo power amplifier. Since I play the 5-string bass, I also had to add a pair of 400 watt powered JBL subwoofers to the configuration just to accommodate the low B and low E strings on the bass. But now my system can handle anywhere from 28 Hz all the way up to 12.5 kHz which is well below range of either my bass or keyboard and way above the range of either the guitar or the keyboard. So, I'm covered for reproducing all the sounds my instruments are capable of. Since the QSC only have two channels, I needed to add a mixer on the front end so I could plug in all three instruments and several microphones all at the same time. The interesting thing is, I got very poor grades in high school physics but, when it came time to put together an amplifier and speaker configuration that could handle all my instruments, I had no trouble at all understanding what I needed to do. You have a lot of money invested in your equipment man. You need to understand what you can and can't do with it if you want it to last.