The disclosure relates to an inlet member for a microphone system in a hearing instrument, such as a hearing aid, wherein the inlet member has a main body portion having a first portion and a second portion, the second portion being provided with a first recess for accommodating a microphone comprising a snout for conducting sound energy into the interior of the microphone, wherein the first recess is provided with a sound channel formed for engagement with the snout of the microphone, where the sound channel at the end hereof facing away from the microphone is acoustically coupled to a third recess in the first portion, the third recess being defined by wall portions that provide a seal to corresponding inner surface portions of a hearing instrument, in which the inlet member is mounted.