I have a remote speaker plugged into audio output of tv ,originally it worked well,now it hums,why is this so?

Solution
One possible explanation is if you have cable there may now be a ground loop creating the hum. This can happen because of improper grounding outside of your home. Since it did not happen when you first connected the speaker it may have been caused by a change in the cable system. You can check this by just disconnecting the cable line going into your cable box or TV if you don't have a box. The solution is to use one of these:
http://www.amazon.com/PAC-Ground-Isolator-3-5-Applications/dp/B001EAQTRI/ref=pd_bxgy_e_img_y
or these
http://www.amazon.com/Viewsonics-VSIS-EU-Cable-Ground-Isolator/dp/B0017I3K9M
One possible explanation is if you have cable there may now be a ground loop creating the hum. This can happen because of improper grounding outside of your home. Since it did not happen when you first connected the speaker it may have been caused by a change in the cable system. You can check this by just disconnecting the cable line going into your cable box or TV if you don't have a box. The solution is to use one of these:
http://www.amazon.com/PAC-Ground-Isolator-3-5-Applications/dp/B001EAQTRI/ref=pd_bxgy_e_img_y
or these
http://www.amazon.com/Viewsonics-VSIS-EU-Cable-Ground-Isolator/dp/B0017I3K9M
 
Solution