Proper breath control is essential in singing.
I find that many singers, men and women, get into their higher ranges and, feeling a need to become “loud”, make a common mistake.
When I first started my career I was a trumpet player and was recognized as having a very high and strong range.
To achieve this range and volume I applied a great deal of “pressure” by pulling my abdominal muscles in as I reached the higher phrases. When applying the same technique to my singing, I found myself straining and belting, usually off pitch, and usually tiring my voice out much faster than it should have.
As I watched and worked with some of the most gifted singers in the world in the pop and classical genres, I observed they did something extraordinary. They actually pushed out on their abdominal muscle as they reached into the high parts of their voices.
So I began to question these artists to find out why they used this technique and how they achieved their success.
What they told me was this.
The diaphragm muscle supplies enough air flow to reach any note and dynamic no matter where the note may be in a song or scale but most especially in the higher ranges.
This is achieved by gently pushing out on the diaphragm as one goes higher. If the high note is somewhat isolated and directly follows a lower pitch (it is a bit of a “jump” from one note to the other), then you can push out right on the highest note.
If the phrase is longer then simply push out gently on the entire phrase.
Note: This is not a permanent condition of singing, but rather a way to demonstrate that is is not necessary to excessively put upward pressure on the diaphragm by forcefully pulling in the abdominal muscles.
Try the new method, you might enjoy it more and have better results.