Cents/Hz confusion/conversions

[k.swafford@genie.geis.com]

 In two posts, Steve Brady wrote:

 >Reflecting on this episode, I was reminded that most musicians
 >confuse cents with hz, so it's good not to take them too literally.

 and:

 >             IMHO, he had probably checked the pitch of his marimba
 >with a Korg tuner, saw that it was 4 CENTS sharp, and took that to
 >mean that it was at 444. It was really at 441, of course...

      I think that this is a useful idea that I intend to file in the
 back of my head for future use.


      Cents to herz conversions are complex.  Newton Hunt posted a few
 cents/hz equivalencies with his Accu-Tuner instructions some time
 back.  I was surprised to find, when I looked recently, that the
 Accu-Tuner manual lists only a few of these equivalencies.  So, here
 is another list:



                CENTS/HZ (ACCU-TUNER) CONVERSION CHART

               Frequency(Hz) to Cents Deviation (Offset)

                          A4 = 415Hz = -101.3c
                          A4 = 430Hz =  -39.8c
                          A4 = 435Hz =  -19.8c
                          A4 = 440Hz =    0.0c
                          A4 = 441Hz =    3.9c
                          A4 = 442Hz =    7.9c
                     May God (and the PTG) forbid:
                          A4 = 443Hz =   11.8c
                          A4 = 444Hz =   15.7c


                    Cents Deviation to Frequency(Hz)

                         A4 = -50.0c = 427.5Hz
                         A4 = -25.0c = 433.7Hz
                         A4 = -15.0c = 436.2Hz
                         A4 = -10.0c = 437.5Hz
                         A4 =  -5.0c = 438.7Hz
                         A4 =   0.0c = 440.0Hz
                         A4 =   5.0c = 441.3Hz
                         A4 =  10.0c = 442.5Hz
                         A4 =  15.0c = 443.8Hz

      All figures were rounded to the nearest tenth and were calculated
 using formulae distributed by Steve Fairchild, RPT, at the PTG
 national convention in San Francisco in 1981.  (Talk about a man
 truly ahead of his time!)
      You are welcome to delete the editorial comment in the middle of
 the table.    @8^)>
                                             Kent Swafford