We used a Byzantine Music piece performed by a well recognized chanter in order to derive experimentally the mean frequencies of the first five tones (D – A) of the diatonic scale of Byzantine Music. Then we compared the experimentally derived frequencies with frequencies proposed by two theoretical scales, both representative of traditional Byzantine Music chanting. We found that if a scale is performed by a traditional chanter is very close in frequency to the frequencies proposed theoretically. We then determined an allowed frequency deviation from the mean frequencies for each tone. The concept of allowed deviation is not provided by theory. Comparing our results to the notion of pitch discrimination from psychophysics we further established that the frequency differences are minute. The Attraction Effect was tested for a secondary tone (E) and the effect is quantified for the first time. The concept of the Attraction Effect is not explained in theory in terms of frequencies of tones.