ZLA Sector 25/28 Feed-cannot hear pilots

[airtrafficjam]

Hi,

While listening to the Sector 25/28 feed for ZLA, I can clearly hear the controller talking. However, I cannot hear the pilots talking to the controller (most times there is nothing or sometimes there is static). Very rarely do I hear a clear reply back from a pilot.

Is this because the planes in the sector are out of range for the receiver that supplies the feed?