In my opinion, if you have a musical background, musical ear or understand pitches and notes, then you will start to hear differences in tubes. All human based. But, I do believe 100% that Elk also are in tune with pitches, resonance and the like, and this is why people will say that elk run from calls when they call (people suck and don't create the right pitches/resonance). There's a definite correlation to how good someone calls, to calling working these days. That and people get so amped up they got 1 bugle response that they start trying to force the issue like human nature wants to do and they forget about Elk nature in that Elk rarely start piping off bugles on 20-30 second intervals. So the human does this and tells their hand to the elk. And voila, "bugling doesn't work."
This plays right into the people that buy into the, "i'll keep moving until I find an elk that wants to play" mentality. They're too impatient to bugle and sit for 15 mins waiting, then slowly ramping a bugling bull up.