Chances are the maker of the CD was trying to be cool and use "cycles" interchangibly with "hz." Unfortunately they are not interchangable. A cycle is one full swing of a AC waveform. From 0 to + to 0 to - back to 0. Hz is defined as cycles per second; the number of times that full swing takes place in a second. 300hz is a frequency. 300 cycles is 300 swings with no reference to time. It could take 5 seconds (60hz), 1 second (300hz) or 1/10th of a second (3000 hz). It's like revolutions and RPM when talking about an engine. Revolutions refers to the number of times the crankshaft turns. RPM tells you how fast it's turning.