[johnharold22]

I recently connected ceiling fan with light kit in our living room which also has entertainment center, amplifier and subwoofer.

When the subwoofer is on and if we switch on/off the fan, subwoofer picks up the signal from the fan switch and makes noise (like thud). Is there any problem with the wiring or fan or it electro-magnetic thing going on here? This noise doesn't persist, sound comes from the subwoofer when the fan switch is in the middle i.e. neither on/off.

 

[jpelzer]

Probably not a wiring problem per se... Are the two on the same breaker (ie, is there one breaker in the basement that when powered off, turns off both the sub and the fan?). You might plugging the sub into a line-conditioner or UPS to avoid the pop, or switch to another outlet.

 

[Yoyizit]

subwoofer picks up the signal from the fan switch and makes noise (like thud).

High current demanded on fan startup temporarily drops the line voltage to your amp?
Try running your amp from a different CB using a heavy extension cord.

It could also be a bad connection in your house wiring that only shows up under heavy current draw. A 10A hair dryer plugged into this outlet should drop the voltage about 3v, depending on several factors.