FIGURE 19. Comparison of the recording performance of four different recorder/microphone combinations on a set of nine advertisement calls of one individual of Bombina bombina at Schorfheide-Chorin Reserve, Germany. All recordings were made simultaneously at the same recording distance, and same calls were thus compared. Call variables were automatically assessed using SoundRuler software (see text for details on the methods employed). Recording equipment as follows: Tascam DR-05 digital recorder/Sennheiser K6+ME66 microphone; Edirol R09 recorder with built-in microphone; Macintosh iPhone 6 with built-in microphone and recording software; Sony D6C cassette tape recorder with Audiotechnica external microphone (recordings digitized with CoolEdit Pro software at sampling rate of 44.1 kHz). Rise time is the time from the start of a call to the point where it reaches the maximum amplitude. Shape-on is the ratio between the rise time and the total duration of a call. Other call properties as defined in the text. Boxplots show median (middle line), first and third quartiles (upper and lower box limits), and non-outlier range (whiskers).