Great questions Roland!

To take advantage of the phantom mix mode in audio conferencing, you
will engage it in the DM mixer the DMTH4 is feeding, ie the DM1612,
DM84 etc.

First remember to put the mixer into phantom mix mode - for the
DM1612, DM1624 and DM812, that is the Configure choice on the top
banner, then click phantom mix mode.

There are two scenarios - the first is when the local microphones are
not amplified at all within the room. In this case, enable all the
microphones in the room for routing to the amplifiers but change the
crosspoint to Phantom mode. Make sure that the crosspoint is at or
about 0dB level. It MUST be engaged (green not grey).

Scenario two is local amplification of the microphones - the mics are
amplified in the room - mix minus perhaps. If any microphones are
OFF at the cross points for mix-minus, chenge them to enabled but in
phantom mode.

Make sense?

Gordon