Shunyata AES/EBU & S/PDIF Required Lenghts

[CGabriel]

Originally Posted by PHC1

The 1.5m is indeed the universally accepted magic length, at least with current technology. . Or odd multiples of it. So 1.5, 4.5, 7.5m

It does in fact have to do with the imperfect world of the transmitter, cable and receiver impedance mismatches. If there was no mismatch, the signal would be perfect with no reflections back at the receiver which is sending the next signal.

The reflection can arrive in phase or out of phase. typically the reflections are not a big deal and are not large enough to screw up the zero point which will determine if it’s a 1 or a 0.

The reflection that screws up the “edge” of the pulses can and does supposedly affect the timing of the clock which is derived from the signal and that is jitter. Not great for the accuracy or the resulting music signal on the other end.

As it stands, imagine a pulsing laser that is transmitting precisely timed signals but the receiver is reflective and sends the laser back to the source. Now that reflection is either leading or lagging the edge and length of the next laser pulse but is essentially extending the “time” of the event.

A water hose spraying into another hose and that hose then squirts the water back into the the first house is the visual example for impedance mismatch.

This is not my area of expertise but I think I understand the basics here. Stick to 1.5m as it was determined to be the lesser of the inaccuracy evils.

[SCAudiophile]

Great posts guys!