I am setting up 9.1 channel HT speakers with Klipsch 120SW and Denon 3700h receiver. All the speakers are working except the subwoofer. When I connect RCA cable from the Subwoofer to the subwoofer pre-out of Denon Receiver 1 the sub starts buzzing. As I increase the Gain of the sub, the buzzing goes high and has set low frequency to LFE or other settings but still no luck. Even the Audyssey test setup did not detect it. I tested the subwoofer by connecting to my phone and laptop whether it's working or not but it works like a charm but not with Denon receiver 3700h with a loud buzzing sound. In the process of getting a subwoofer working
1. I tried getting different RCA cables from Amazon, insignia and etc which did not work.
2. Bought the best buy TruConnect ground loop isolator then connected the RCA cable from sub with GLI to receiver still the problem exists.
3. Tried plugging both Sub-woofer and receiver to same power outlet, different and surge extension outlet.
What am I missing to get the buzz to go away permanently and sub-working? I have been testing this for the last 2 days and sweating why this not working?