I have wondered the same thing until I came across a 112 and looked inside. If you look at this picture of this 112 reedbar currently for sale on eBay, you'll see a large block of steel bolted to the reedbar. Mine had a thin piece of brass shimstock between the steel block and the reed screws (I assume for full contact across all of them?). When I removed this block and played a few notes, they were very dull sounding and short-lived. Reinstalling the block and shim brought these reeds back to life. It was as if the reedbar casting was too thin and wimpy in this upper section. Adding mass must improve resonance I assume? The upper reedbar of the 140/200 series is indeed much more massive and maybe this is why. This makes me think of the old Hurdy Gurdy hand-crank tiny music boxes. Winding them in open air and they sound soft and wimpy, but placing them on a wall and they can fill the room.
