The frequency parameters of call type 1 lie between 30 -- 38 kHz , have most energy at 33 kHz .
The frequency parameters of call type 1 lie between 30 -- 38 kHz , have an average duration of 2.5 ms .
The frequency parameters of call type 1 lie between 30 -- 38 kHz , have most energy at 33 kHz and have an average duration of 2.5 ms .