From: WVE~ol.com Date: Fri, 27 Aug 1999 22:27:57 EDT Subject: =?ISO-8859-1?Q?Reed=20design,=20was=20Chromatic=5FRattle=5F&=5FH?= =?ISO-8859-1?Q?ohner=B4s=5F? In a message dated 8/27/99 4:07:11 PM Pacific Daylight Time, wpri~nsinc.com writes:
> ...hey, great! You just answered a question that I hadn't quite > formulated. So brass isn't the sacred "bell-metal" we've been led to > believe?
I think not. Copper alloys make great bells. Beryllium Copper (2% Be & 98% Cu) has a good resistance to fatigue but its brittleness makes offsetting/voicing the reed difficult. However bells radiate sound from the vibrating metal and the sound radiating directly from a harmonica reed is negligible. Bells must conserve the energy of the clapper strike and radiate it over an extended period of time. A reed has a relatively powerful source of energy continuously available....the airstream. What you hear is the chopping of the airstream as in a siren.
The main advantage of brass/bronze is that it is softer and machines (and tunes) more easily. The cutting tools last longer and that makes manufacturing cheaper.
> So we could have tougher material, less prone to metal fatigue > and still get the same sound?
Yes. Most accordions use steel reeds. It doesn't need to be stainless because players don't breathe into accordions. I don't have the statistics, but I don't think that accordion reeds fail as often as harp reeds. According to my materials texts, the proper grade of SS has a much better fatigue life than a copper alloy. I have never tested any reeds to failure under controlled conditions.
A SS reed equivalent to a brass reed that will sound the same pitch in the same slot and respond the same is a bit thinner where it bends near the rivet end and a bit thicker near the tip. This is because the modulus of elasticity of SS is greater than brass and the density of SS is less than brass.
> Now _you'll_ be the > blasphemer and I'll just sit back and get an education.
Blasphemer/skeptic/killjoy is a familiar harp-l role for me.
> So--did you make your own reed?
Yes. When I retired, it was my intention to make harps with magical sounds of exotic materials. Sadly, I found that, provided they were generally suitable for the application, differences of comb, cover, and reed materials had no perceptible effect on the harp tone. In the process, I made a little shoebox-sized horizontal mill for cutting reeds from virgin stock. In the last few weeks before SPAH99, I replaced the handwheels with stepping motors, hooked it to a used 486 PC and wrote a QBASIC control program for CNC control. I can now repeatibly cut curved & tapered thickness profiles and reproduce the same design much more closely. Before SPAH2K, I plan to design, cut, install, and tune replacement reeds for at least one whole chromatic.
My purpose is to experiment and not to make money. I may be reinventing the wheels already invented by the harp manufacturers. However, they won't share their proprietary technical knowledge. My limited empirical knowledge of commercial reeds I learned from reverse-engineering my Hohner harps.
