Headset input crosstalk, or how to mitigate the effects of common ground resistance
through 4-wires cable splitting at ~1 mt from the connector.


One meter of thin cable has indeed some resistance. But you can eliminate this almost altogether by splitting close to the connector, which makes the circuit look like this:







simulate this circuit &ndash; Schematic created using CircuitLab

Note: R1-R5 are the resistances of the copper cables.

In other words, a shorter common wire will have less internal resistance and thus less crosstalk.