And the goal would be to replicate the actual animal sounds as closely as humanly possible to what the animals say weather they are distress sounds or coyote vocalizations with as little distortions as we can . Every predator has heard distress sounds of a lot of different animals by the time they reach adult hood that's what they do for a living hunt and kill so for me it would be very interesting if there were tests done to tell which e-calls actually had the better reproduction of sounds and have the least un needed back ground noise . They can lock in on a mouse walking in the grass under a foot of snow from 10 feet away so I know that they can hear very subtle differences in tones and frequencies as well as back ground noises . This is an interesting thought that I have had in the past myself . I have tried a few different e-calls but with my limited range of hearing I wouldn't really call it a study of the sound reproduction , just an interesting trial for my own satisfaction .