I played an open aperture for years. It produced a good tone (although no better than my current embouchure). I could play to high A above high C. For me it required too much work to maintain my sound, range and endurance. It also needed more mouthpiece pressure to play high than I wanted to use. That led to endurance concerns when I played long shows with multiple sets. I also sometimes had lip swelling the day after a hard gig. That required a lot of warmup. I didn't play full-time and I couldn't spend 4+ hours a day to maintain my chops.

The other approach was taught to me first by one of Jakes' students then by Jake. It required everything to change.

It was not possible to use the spread aperture and simply back off the mouthpiece pressure. Nor was it of any help to add lip curl to spread chops. It simply didn't work.

When I changed to a closed aperture and started using lip buzzing like Mendez then it was possible to add lip curl, and lip  compression and back off the mouthpiece pressure. That increased my range and my endurance.

Jake told us to make playing mental rather than physical. He often said 15 minutes of smart practice was better than 4 hours of hit and miss.

Due to his health Jake himself stopped practicing and playing during his lessons. He did still record. After several years of this Jake stopped playing entirely. He said that he wanted to stop before anyone noticed any flaws in his playing. I had already left him by then but Mike Vax told me of one of Jakes' trumpet parties about 2 years before his death. Mike went to the hall closet and took out Jakes' horn. He landed it to Jake and told him that he should play at least once for his current batch of students. Mike says that Jake played with fire, passion, and the beautiful sound that he always had. To the best of our knowledge Jake had not played a note in 2 years. I know that Keith Wood (who helped on Jakes' book) lived with him. And Jake didn't play for at least a year.

When asked about how he could play so well Jake replied that "Playing is mental and air not physical." If he had needed hours a day of practice that would not have been possible.

Jeanne advocates letting the tongue support the lower lip. Claude Gordon taught anchor tonguing. That forward tongue position helps open aperture players greatly. This happens in a couple of ways. One it closes part of the aperture hole allowing the player to fill the aperture with a lesser quantity of air. Remember the aperture has to be filled up or the tone suffers. A big aperture needs a great deal of air. The tongue helps to cut that amount down to a manageable size. The tongue also helps to prevent the dropping of pitches or tone variation on long tones.
 

I've converted hundreds of players to a closed embouchure setting in the last 2 years. So far everyone likes it better than their old style. Will they become the next Maynard Ferguson? Well I have a couple of students who might but 98% will not. It does let them play with a big full sound and increased endurance with only having to spend an hour a day in practice. For the player who can't spend 4-8 hours a day practicing a closed aperture is the best thing going. (I am working on a new concept.)

Even some players who did spend a lot of time playing used a closed setting and some lip curl. Don Jacoby (Get your CD from Donovan You really have to hear him play Napoli). Mendez, Harry James. How about todays players Dennis Najoom plays this way as does Arturo Sandoval. Arturo is a lip buzzer. He has the loudest, strongest double C lip buzz you will ever hear. These are closed aperture players.
 

(Before the CG group chimes in, I teach and write about embouchure development. I deal with the physical side of playing, the mechanics. Arturo does use and teach free lip buzzing.)

Information about my trumpet & embouchure books.
http://www.BbTrumpet.com
 
Best wishes
Clint 'Pops' McLaughlin