Daren, Questcher, the reed chamber is sealed. air goes into the chamber and then release once the pad is opened below the reed. unlike the Clavietta where the air enters the air chamber then released after the pad is opened then to the reed.
Path of air
Eolina = air to Chamber to Reed to key release to sound hole to sound chamber then out of the Eolina .
Clavietta = air to Chamber to key release to Reed/direct to sound chamber sound exits out of Clavietta through the top of the keys.
Melodica-Me