An apparatus for objectively assessing in-situ an acoustic seal of an in-ear device in field environment conditions is disclosed. The apparatus comprises a controller unit operatively connectable to a sound source and to a sound measurement device, wherein the sound measurement device may be selectively engaged in a first position relative to an in-ear device to measure a first sound level outside the ear canal, wherein the sound measurement device may be selectively engaged in a second position relative to the in-ear device, such position occluding a passageway in the in-ear device, to measure a second sound level inside the ear canal, a supporting device that is mountable on the sound source, releasably supporting the sound measurement device thereon.
