Why does my subwoofer make a "popping" sound when I turn it off? (1 Viewer)

[Antonio]

Hello,

I have a Paradigm PDR-8 (yeah I know, a weakling but I cannot have the house shaking because I live in an attached house and neighbors will complain) subwoofer and noticed that it makes a "pop" sound everytime I turn it off. It will make that sound regardless of the position of the volume knob on the sub.

My questions are: 1)Is this normal (common) behavior and 2)if I should leave the subwoofer on all the time? Thanks for your input!

~Antonio

 

[MarkO]

When power is aplied to the transformer a large electronic field is created around it. These are simply stray electrons that have been ejected out of the windings because the transformers windings are overly saturated. All conductors have this leakage of electons. Since a transformer is nothing more than a bunch of wires wraped around a center core the field around it can get quite large.All these suspended electrons want one thing, and that is to get back in. Since power is apllied to the tranfsformer there is sort of a shortage of vacancy so to speak. When you turn off youre sub the field around the transformer sudenly collapses and the suspended electrons rush in. This creates a very short high current condition which has to be discharged somewhere. If it is not discharged phisicaly to some sort of a load it could arch across to sensitive electronics inside the sub amp. So many manufactures simply let it discharge in the speaker coil where no damage is done to sensitive electronics. "pop"

 

[Antonio]

Thanks, I've always been wondering about that. Sorta like Lenz's law right? I take it that you are an EE?

 

[Chris Tsutsui]

I get it every time I turn off my amp which is hooked to my computer. It sorta bugs, but it also assures me I pushed the button right and turned the amp off.

 

[MarkO]

Not really an EE. I wish I was that smart. I deal more in the repair and dio of circuits on small aircraft where even the collapsing field from a small switch relay can cause problems.