Helixnet : Why do I hear a robotic sound when listening to two channels at the same time

I have user that using a Helixnet Remote station (HRM) and when they listen to a 2 different PL channels there is a robotic sound (like phasing) , when they listen to either channel by itself , the sound is clean

The show caller is using a MS-704 unit , which is wired into a Helixnet / Arcadia system , the Sound ops is listening to both channel A and B from the MS-704

solution

If you have two analogue interface inputs into the system the system does not know that they are the same audio so it goes twice into the HelixNet mixer with (likely) different arrival times.

The HelixNet/IV Core does not guarantee synchronous of playout of interface audio inputs.

Once summed they will create something called a comb filter which then gets worse as you add more inputs with the same audio with different arrival times to the listener.

If instead of a MS/RM-704 the user was using a HRM they would not hear this, as only 1 copy of the audio would be arriving to the HelixNet listener, regardless of how many channels they would be talking on.