I hear from lots of players that they don’t have a lot of success with blowing Ro. The fact is, it’s hard to get the sound you want. I’d say there is no one at all who could get a sound they’d be satisfied with 100 times out of 100 tries.
Indeed,if there were someone who did, that would simply mean that they aren’t trying to improve. At any level you play at, you should always be striving to improve. This means it’s natural not to be satisfied with your sound.
How,then, do you get this better sound? If you can’t get a good Ro until you are fully warmed up, then that’s possibly a sign that you have too much tension in and around your mouth.
In other words, you are using so much muscle to blow at full power that the muscles around your mouth need to warm up before they are up to the task. This way of blowing tires you out quickly.
Try to relax as much as possible, so that you will be able to play for longer stretches. To do this, increase the inner volume of your mouth. Some images you can try for this are blowing with your mouth shaped like you are taking an in breath, or like you are trying to suppress a yawn.
Something similar can be said for those who have trouble with the higher octave. One way to produce a high octave note is to increase the speed of the air coming out of your mouth.
If you do this by tightening up the muscles around your mouth to decrease the sizeof your lip opening (particularly the vertical space between your lips), you will end up with a lot of white noise in your sound.
To get a smoother sound, try using the image of “blowing lots of air farther, just like trying to blow out a candle beyond arm’s reach.
It’s also effective to try blowing notes as softly as you can in the high octave. One important part of the practice of blowing Ro is learning how to relax your mouth.