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Author Topic: 30 dollar train wreck  (Read 122 times)

Offline Dibbs

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Re: 30 dollar train wreck
« Reply #15 on: December 02, 2020, 03:13:11 PM »
Personally, I feel bore smoothness makes a perceptible difference as do most (all?) instrument makers but I've never experienced it personally or seen any studies.

In Acoustical aspects of woodwind instruments p11 Nederveen states

"The velocity of sound in the tube is slightly different from that in free space because of the action of friction and heat exchange of the air with the wall.  In practice this causes a damping and a change in frequency."

Friction is obviously greater if the surface is rough so, on the face of it, one would expect bore smoothness to affect both tone and intonation.  However he later (p15) calculates the thickness of the boundary layer to be ~0.05mm at 1000Hz.   He calculates this purely from the viscosity and density of air.  There is no "roughness" parameter. 

I don't know what to make of that.  Maybe the calculation assumes a perfectly smooth bore surface because the roughness effect is considered negligible but he states no such assumption.

Offline Airflyte

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Re: 30 dollar train wreck
« Reply #16 on: December 02, 2020, 07:12:01 PM »
So plastic Bundy's and Vito's technically have the best bore surfaces "teamed up" with inferior bore dimensions?
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