Advantages of Cents Notation Examining the semitone A to B-flat at different points in the range of the piano will illustrate the fact that if expressed in cents, every equal tempered semitone is the same. Expressed in Hz difference, every semitone is different. The interval value in cents expresses the ratio of the frequencies, which is the same for every equal tempered semitone. Included with the semitone intervals above is an evaluation of the deviation in Hz needed to equal 5¢, the nominal just-noticeable difference for these pitches. Note that the range represented by 5¢ increases from less than a tenth of a Hz at the low end of the piano to about 10 Hz at the top end of the piano. If f 1 = Hz and f 2 = Hz then the interval is cents. Just noticeable difference in cents