Bob -- This was discussed about a decade ago. Somewhere in my records I have a more-exhaustive summary, but here is an approximate formula for speed of sound against temperature
http://www.sasked.gov.sk.ca/docs/physics/u5b22phy.html v = (331 + 0.610t) m/s which suggests for each degree C temperature rise a wind becomes 1200 log(1 + .610/331) ==> 3.19 cents/degree celsius There is a counteracting effect of the instrument flattening due to the expansion of the tube increasing length, but IIRC my ancient calculations this effect for brass is only about 1/20 the magnitude of sound velocity change. 7 degree F is a little less than 4 degrees C, so expect a sharpening around 12 cents. Of course, this ignores the effects of your breath cooling as it travels down the tube, at a rate that depends on how much you have been blowing very recently, the difference between the external temperature and your body temperature, and indeed on the velocity of the air stream (which depends on dynamics, tessitura, etc. etc.). _______________________________________________ post: [email protected] unsubscribe or set options at https://pegasus.memphis.edu/cgi-bin/mailman/options/horn/archive%40jab.org
