A hearing instrument includes a main housing, an in-the-ear-canal sound receiving unit, and a sound emitting unit. The sound emitting unit may be located completely in the ear canal or may be linked to the ear canal by an acoustical tube. An acoustic blocker separates the sound emitting unit and sound receiving unit. The main housing is configured to be located outside of the ear canal and includes processing circuitry that is operable to process signals. The acoustic blocker is configured to at least substantially occlude the ear canal and acoustically isolate the sound emitting unit from the sound receiving unit.