This is the non-negotiable first step. You need a file that announces each channel individually.
The first step is a basic "ping" test to ensure your cables aren't crossed. 5.1 speaker test
Every modern receiver (Denon, Yamaha, Sony, Onkyo) has a built-in pink noise generator. This is the non-negotiable first step
If you are connected via a PC, you can use browser-based tools. Ensure your browser has access to your surround output. 5.1 speaker test