Do you really believe this. My understanding is that any low signal level cable over 3 metres no matter how whoopdido is going to have high frequency roll off. And what about phase shifts and internal reflections within the cable itself.
I find it hard to believe there is no degradation.
No- I don't 'believe' it- I know it. I've run similar lengths for microphone signals myself- with no rolloff. Its helpful to keep in mind that a properly set up balanced line system is also low impedance (600 Ohms is typical) and the low impedance aspect allows you to run longer connections.