Phosphorus bronze reeds just like the Hammond 44. I would assume that the wood would absorb some of the sound as wood normally does. I do not see any views of the actual rear of the keyboard and do not see any vent holes so I can only assume that the sound comes from between the keys and at the rear of the keys. The Hammond 44 and hyper have vent holes so there is plenty of volume. Just how low level it is. Though the volume level dose not really bother me. If you consider the Clavietta’s volume which is low the sound can still be amplified if needed. My Diamanté Wind Vox #001 is less than than that of the clavietta and the #002 version is even less. They were designed to be used with amplification and special effects so not a big deal for me. Now if I wanted to play in an acoustic group outdoors I would really consider the output.