I wouldn't just go by the sound. I killed a wily old bird last year that had 1 5/8" spur on one leg, and a broken spur (3/4) on the other. He was a smart and fat old beast with a big old paintbrush. His gobble sounded like a toilet flushing.

I've heard jakes that sound like Supertom.

Generally speaking, however, a jake will sound raspy and choppy. As noted earlier, a jake's tailfeather tips are longer, and not in a uniform half-circle when strutting. The middle feathers will be about 1-3" longer. Another sign is beard/spur length. A jake will have a short beard and stubby spurs.

There are exceptions here, too, as sometimes birds will lose their beards and start anew. Those will be mature gobblers with maybe a 2" beard.

You usually can tell, based on the totality of the facts. Jakes will also weigh less, generally.

If you see a strutter and his beard is in the grass, he has a big, pretty, round fan and a flock of hens around - it's no jake.