On Dec 1, 2011, at 11:33 AM, andy butler wrote:
The most common nominal level for consumer audio equipment is −10 dBV, and the most common nominal level for professional equipment is 4 dBu.
In most cases changing the volume setting on the source equipment does not vary the strength of the line out signal.
Not that Wiki knows it all.
The impedance of output +4 db seems to overload the line in on some of these consumer DJ devices.