4. Frequence level
George Archibald had suggested that one of the differences might be the pitch at which the individuals are calling; to study this, for the J and the K-RC each 14 calls have been quantitatively evaluated by computer calculation of the "powerspectrum" (= individual acoustic fingerprint), and the main frequency (which is not necessarily the one with the highest amplitude, but the highest strong basic frq used.
The resulting "acoustic fingerprints" are documented in the graphic attachments (due to the program which I have developed, and due to standardization, I am showing only frequencies between 600 and 1200 Hz); nonethless, the others are available if necessary.)
As can be seen in the Excel sheet table, the results are in average:
it is interesting (I have never seen this before), that in 3 pairs the f is calling ar a lower pitch than the m; in no sonogram from Korea something like this can be seen.
This difference (about 100 Hz between respective males and females, and also about 100 Hz between m and f both in K and J) might be simply due to size, which itself might be due to food ressources, and / or to the genetic basis.