Originally Posted by Kevin_Hsu
Hard to say, but I've heard a few others report that as well. It's quite strange. With the y-adapter, that does double in the input voltage going to the sub so it ends up adding an additional 6 dB to the input signal. So technically, with the y-splitter, the channel level should be around -4 or -3 dB.
I'm planning on running AccuEq again now that I have the y-adapter to see if it helps my 686 set better levels automatically. If it still acts funny, I will just go back to setting the sub gain at just over 10 o'clock and set the AVR sub level to around -3dB using the dB app on my phone.
One question on mic placement...I'm using the Onkyo mic on a high-end photo tripod (carbon fiber, ~$1500 including the head) so it is pretty good about not transmitting extra vibrations, but when I set it up, should I keep it solely on the sofa cushions and not let it touch the floor to make it as isolated as possible?