Parents station is too quiet

Are a few weeks, the baby monitors now already in use and I am very pleased with the way the device works. The nightlight in the shape of the moon is very discreet and not too bright. The music box we have to undress. What I liked a lot that you can adjust the sensitivity on the parent station. The walkie-talkie feature is my older daughter super. However, the parent station is much too quiet, so two points are deducted. For the night and when one is alone while watching TV, it's super. But once you talk with more than one person, no longer hear the baby monitors, although it is set to the maximum volume.