I have dual RCA cables that I'm trying to plug into a mixer using RCA to TRS adaptors. They don't sound good, there is cancelation, and I know I need RCA to TS adaptors--they are in the mail.
My question is--what exactly is happening with the signal from a wiring perspective? I understand that the TRS adaptor is expecting red, black, and shield, but the RCA is only supplying two of those.
I want to know exactly WHY it sounds bad.
* UPDATE / EDIT: I am now using RCA to TS adapters and the sound is fixed -- as expected. *
It's a Mackie mixer and the line in is balanced / unbalanced. I assume that the line in will expect TRS to be balanced, and TS to be unbalanced. I am assuming that the RCA cable's signal is doubled and put into both the tip and the ring. The mixer is treating Tip and Ring as a balanced signal, but it's not polarity-reversed like a balanced signal, instead it is a duplicate signal, causing cancelation.
The rest, I'm not sure if it's relevant but: It starts with an iPod, TRS headphone out carrying unbalanced stereo, split with a Y adapter to dual RCA, dual RCA cables are both adapted with a RCA to headphone TRS, which are each adapted from headphone TRS to 1/4" TRS before going into the mixer line in. It doesn't matter if I put them into the stereo pair channels or mono channels, it doesn't matter if I only plug in one of the cables or both.