All given in Hz.
**********************************
f_4Harm_VM =
          1923.226
          1923.913
          1928.261
          1929.112
          1930.594
          1931.361
          1931.947
          1931.998
          1932.128
          1932.418
          1935.967
          1936.336
          1936.702
          1937.353
          1939.667
          1940.281
          1940.633
          1940.670
          1940.975
          1955.202
          1956.142
          1960.979
          1961.583
          1968.677
          1969.449
          1969.772
          1969.814
          1978.202
          1978.89
          1980.715
          1981.563
          
**********************************
  diff(f_4Harm_VM)
     0.6871
    4.3484
    0.8510
    1.4817
    0.7670
    0.5860
    0.0514
    0.1299
    0.2901
    3.5488
    0.3687
    0.3666
    0.6506
    2.3142
    0.6141
    0.3519
    0.0368
    0.3050
   14.2266
    0.9407
    4.8364
    0.6047
    7.0937
    0.7714
    0.3237
    0.0414
    8.3878
    0.6882
    1.8255
    0.8477
    
**********************************
max(f_4Harm_VM) - min(f_4Harm_VM)
   58.3374