Paradigm subwoofer noise when turn on and off?


2014-07-29 12:53 pm
Pdr-10 v4, didn't use for a long time. Now when turn on, there is one pop sound; when turn off, after 5 seconds, fart sound can be heard for around 5 seconds.

Don't know what happened to it? I changed the power outlets, and tried different receivers, the same result.