Buy High Pass Filter or KAB RF1?


Is a $25 high pass filter as effective for rumble as the $180 KAB RF1?

I would rather spend the lesser amount. Thanks! 
craigert
My woofers DON’T flop with the volume turned down. 
It started out of nowhere on my AJA album Black Cow. Something wasn’t right so I switched to Led Zeppelin II and it was rumbling on that too!
The weird thing is why are my front speaker drivers rumbling too when signals below 80 Hz are being sent to my sub?
Craigert, Re this last post, define "rumbling".  Are you hearing a noise or are you watching the drivers do a dance, in and out?
The weird thing is why are my front speaker drivers rumbling too when signals below 80 Hz are being sent to my sub?
Looking at the manual for the AV7704, I see that depending on some menu settings frequencies below 80 Hz may or may not be sent to the main speakers, in addition to being sent to the sub.

Also, I don't think an answer has been provided to a question I stated earlier, namely "does the problem still occur when the sub is not operating? "

Regards,
-- Al
  

Oops sorry I forgot to check your question Al. When I get home tonight I will play a record without the sub and will report back!

Thanks for reading my manual!

There was only one time there was audible noise that came from one of my front speakers, but it’s pretty much just noiseless extra flapping of the cones and woofer.