I've been struggling to measure the duration of my field-recorded bat calls well (with decent amounts of reverberation). Manual measurements are common in my study field using spectrograms. Using a graphical user interface, the 'borders' of the bat call are manually outlined - and the duration is calculated. I suspect manual measurements won't be reproducible within and across observers - but this method remains rather dominant in my field. Finding a proper tool and assessing its utility to my bat calls may take a long time however.
I tried looking for a study comparing the effects of using spectrograms on such measurements but failed to find any for bat calls. Should I still go ahead with spectrogram based manual measurements, can anyone point me to related literature?