Miele DA 5106 Operating And Installation Instructions page 48

Connection for air extraction
Extraction mode with external motor
To minimise noise from the motor in the
kitchen, the silencer should be
positioned in front of the external motor
 if possible, or, if the ducting is long,
above the exhaust socket on the
cooker hood . In the case of an
external motor located inside the
house, fitting a silencer behind the
external motor  reduces the noise of
the motor outside the house.
48