I had a DK Grey Fox distress sound when I first started calling predators in the early-mid 90’s. I had no idea what I was doing and thought it was a junk sound. As time went on and I had some success with rabbit sounds and Johnny Stewart gray fox pup distress. I rarely ever played the DK sound after that until bunch of years later when I converted the sound file from cassette to an mp3 and loaded it on my Minaska Bandit caller for kicks. First time I made a set with it I called in a grey in the middle of the day here in Central NY.
The best stuff out there?… I don’t think so. Effective?… In the hands of someone with some experience and knowledge of predator hunting/calling… It can be.
Sorry to hear of his passing.