My bass speaker malfunction?

i bought this altec lansing speaker model bxr 1220 with sub-woofer 10 months ago.not long ago its bass malfunction when i turn up volume near its maximum volume.when i switch off the speaker and reduce the volume,the bass is ok again but only for a while.my friend told me that the problem is the IC(integrated circuit) but he wasn't sure about it.i wanna know what is the real problem and how much it would cost me to repair it.pls help me.thanks