Sub-woofer "POPS" when turning off [Archive] - Audio & Video Forums


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05-13-2004, 11:35 AM
My AR Sub "POPS" when it shuts down automatically


it is soo annoying when listening a lower volume part of a track for a while and then all of the sudden "POP" the sub lets me know he just shut off

Any ideas, or experiences, or anything???

the sound is good thou.

05-13-2004, 08:10 PM
Return, Repair???
It seems the muting relay is not functioning properly.

05-14-2004, 10:38 AM
I did returned and the new one does the same is design defect I think

05-25-2004, 08:49 PM
I had the same problem. I bought a line coditioner that switches components in a certain order so there is never a "pop". I think it turns on reciever then sub and turns off the opposite. May have backwards?? I am not sure if there is an inexpensive (<100) component that does this. Have you tried plugging the sub in the receiver's switched outlet?

05-25-2004, 09:55 PM
I'll try anything ........I even ask the sub gently...."Please can you shut down quietly?" response so far........

05-25-2004, 10:15 PM
You might have to do a chant and dance
Maybe even a sacrifice.

05-26-2004, 07:31 AM
hahahaha......I'll try the dance but no sacrifice.........all type of life is too valuable to do that stupid crap.

05-26-2004, 07:42 AM
.... Have you tried plugging the sub in the receiver's switched outlet?

Not a good idea. That switch is normally rated up to 100W only or you may end up blowing the fuse.

05-27-2004, 07:08 AM
I have a Klipsch SW8 sub and have replaced the amplifier once (with an amp from an SW10), both amps "thump" when shutting down. Usually I shut it down after my other gear if off. If I forget, then after a while don't remember if it off or not, the "thump" lets me know it's off. I believe it happens because powered subs have high-wattage power supplies with big capacitors. When powered off the caps discharge through the speaker.

A better design would be to have the power supply connect to the speaker through a double-pole/double-throw relay. When powered on, the relay's normally-open contacts close supplying power to the speaker. A high-wattage bleed-off resistor is connected to the normally closed contacts. When shut off, the relay shuts off opening the contacts to the speaker, but closing the connection to the bleed-off resistor. The capacitors discharge through the resistor and dissipated as heat, stopping the "thump". I'm not really bothered by the thump, so I haven't really tried this, but the concept should work. Similar to picture-tube bleed-offs. What I would really like is a circuit to reduce the 60Hz hum present in almost all powered subs I've heard.

I use the SW8 for upper/mid bass in my bedroom system and enjoy it, but my other sub is passive and driven by a Marantz M700 amp which doesn't thump. Also in my main system I have my Legacy Focus woofers biamped through a Yamaha M-65 amp with no thump.