Funny. The Chuck Yeager drawl is what I thought of, when you mentioned the study. I think modern equipment brings the most out of a low baritone voice, but in the old days, when they had squeaky equipment, maybe the Chuck Yeager nasal voice came out better? In the early days of the phonograph, a tenor came out better. Even Bing Crosby, a great baritone, had to sing tenor until, they had hi-fi recording and playback equipment after the war. Two way radios were some of the last pieces of equipment, you listen to, that were made to sound better. I guess, they figured, it's often full of static anyway, so what's the use?