I'm using a -25Db attenuator cable (this one) to connect an audio mixer to my camera. Now, I've tested the cable by connecting my DAP to the camera, and it works just fine. But when I connect the attenuator cable, even without an audio mixer plugged-in, I hear background noise. When I turn on the audio mixer but don't have any input sources for it, the noise is even louder. When I connect a radiomic to the mixer, the loud noise is still there, coupled with the audio from the microphone.
Can someone help me figure out what's going on here? Am I somehow using an attenuator cable incorrectly? I doubt it's faulty considering that connecting a DAP to my camera results in a good, clean signal and no noise on the line.