This study investigates the effects of frequency variance on duration perception, using musically trained subjects. In the experiment three silent duration intervals were examined (4.75, 5.00, and 5.25 seconds); each interval was preceded and followed by tone markers. The onset marker was preceded by seven discrete tones one second apart, on the frequency 174.968 Hertz. This established a pulse or an external standard time measure. The subjects made judgments as to whether the offset marker fell "before," "on," or "after," the pulse. The offset marker had a variable frequency. In the study, the direction of the frequency change, the distance of frequency change, and the mathematical intervallic relationships of the two frequencies show possible influence on duration perception.