aura bass shaker setup
 

Hi, I have my new sofa with aura bass shakers installed. :-)
My main receiver is a pioneer 811 and is my main receiver, my 2nd
receiver(pioneer 557) I would like to use as a powered amp for the bass
shakers.
If I hookup the audio out directly from my satellite to the second amp the
bass shakers work fine. The bass shakers are simply connected to a
speaker out from the 2nd amp.
If I hookup the bass shakers the way they are supposed to be hooked up, Y
splitter off of sub out of main receiver, 1 part of y to sub, other part to
input on 2nd amp, I don't get any effect from the bass shakers.
I don't have the manual for the 557, anyone know of the settings I should
make to get effects from the second sub?