Rob Kiddell writes: > On behalf of someone offline, I'm looking for the chart that comes with > most electronic tuning machines that converts hz frequency to cents. >Essentially this person needs the chart to check the aural >temperaments of his students (including me) with a vintage Conn strobotuner. >If anyone has the data stashed somewhere electronically, a copy would help >immensely. Failing that, if anyone knows where to obtain one of these >charts, that would be appreciated as well! > Bob: Here is the general method for converting beats to cents with a computer. I have given the syntax in "C" since that is the computer language I use, but this can be done with a spreadsheet too. // first figure the beat ratio: beatRatio = (beats + hertz) / hertz; // next use a log10 function to convert to cents: cents = log10(beatRatio)/log10(2.0)*1200.0; For example, to figure the cents offset for one beat sharp of A440 is: beatRatio = (1.0 + 440.0) / 440.0 Then plug that number into the log10 function above and you get about 3.9 cents. (Credit where it is due: these formulae are from Steve Fairchild, RPT) >(BTW, I ended up passing a dry run at the tuning test, under three >RPT's, but lack of CTE's up here means I'll have to test again. At >least the teaching worked!) Congratulations on passing your "dry run" tuning test. Taking a pre-test for the PTG tuning test dramatically increases the likelihood of passing the real test, in my experience giving the test. I wonder though, about using a "vintage Conn strobotuner" for checking aural tuning. These instruments are generally only accurate to 0.5 cents at best, and the tuning test needs to be scored with an instrument that is accurate to 0.1 cent. I think the Conn could easily give a false reading as to whether a student would pass the test or not. It would only be useful as a very general guide. A good aural tuner can hear errors of as little as 0.2 cents, _maybe_ 0.1 cent on a good day, so the 0.5 cents accuracy would be a problem IMO. A better check would be to use an Accu-Tuner, which has resolution to 0.1 cent (and accurate to 0.04 cents). If you can tune very close to an FAC, Chameleon, or other good aural tuning recorded in an Accu-Tuner, that will avoid having to do all those hertz to beats calculations! Hope that helps. Dean ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dean L. Reyburn, RPT Sanderson Accu-Tuner REYBURN PIANO SERVICE, INC. Authorized Distributor 2695 Indian Lakes Rd, NE "Software Solutions Cedar Springs, MI 49319 USA for Piano Technicians" NEW Toll free: 1-888-SOFT-440 email: dean@reyburn.com Fax: 616-696-8121 Check out Accu-Tuners and our software on the web: www.reyburn.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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