I can play C pedal quite well but I found that I actualy change my embouchure when I do it. Does anybody knows how to doit with the same embouchure. On the other hand, i have read in the Arbam`s method that every single person has a diferent embouchure(i have a 2/3 upper lip, 1/3 lower lip) so why are the people who say some are wrong?

First of all, I'm no expert. I'm just a high school kid. Secondly, no, I don't know how to keep your embouchre the same... However, it is better to have the majority of the mouthpiece on ur lower lip because the lower lip muscle is stronger and if you have less of the mouthpiece on your lower lip, you increase te flexibility of your upper lip. I recently read this in the book "Embouchre Builder" by Lowell Little. Before this, I had a 1/2 and 1/2 embouchre. However, I tried a 1/3 or 1/4 upper, 2/3 or 3/4 lower and it instantly increades my range and stamina.

First of all, I'm no expert. I'm just a high school kid. Secondly, no, I don't know how to keep your embouchre the same... However, it is better to have the majority of the mouthpiece on ur lower lip because the lower lip muscle is stronger and if you have less of the mouthpiece on your lower lip, you increase te flexibility of your upper lip. I recently read this in the book "Embouchre Builder" by Lowell Little. Before this, I had a 1/2 and 1/2 embouchre. However, I tried a 1/3 or 1/4 upper, 2/3 or 3/4 lower and it instantly increades my range and stamina.

there are embouchures better than others, but use what you find to be the best. Pedal notes do improve range. But who said range was always playing highnotes? Range is low and high, and pedal notes improves range going downwards...and probably helps playing higher. But yea, pedal notes are a pain to get with your normal embouchure. You gotta bend man, BEND.

Yes, pedal tones will definitely help your range development. Slurring exercises will be of particular benefit.

Percentage of upper and lower lip inside the mouthpiece rim is going to vary from person to person depending on what is most comfortable for each individual.

Relatively, don't try to rush the process. For some it happens more quickly than others. For certain, it takes practice, practice, practice. For beginners at least 20 minutes per day, 30 minutes for intermediate, and 45 minutes or longer for advanced level.

I'm age 60 and started learning when I was age 9. On most days I practice two hours during the morning and two more during the evening I know students can't do that during the school year, so evening practice sessions become even more important. If you think an hour of band class will get it done, you're just kidding yoursefl. If I miss one day, I know it. If I miss two days the guy in the next chair knows it. If I miss three days, the conductor knows it. Daily practice is important.