I know I talked a bit about this 283 posts ago – but I thought I’d add a couple of things.
The most common complaint I hear from amateur singers is that they run out of air before the ends of phrases.
Then they ask me to teach them how to breathe.
However, though taking in and using more air is a good idea, it won’t solve the problem if either of the following things are still happening:
Tongue cutting off sound. The English language is brutal for singers. If we’re pronouncing words the way we’d say them in rapid fire conversation, the tongue is in constant motion – and constantly tensing and blocking the flow of air and sound. So when we think we’ve run out of air, the truth is often that the tongue has shut off the air flow. This is particularly noticeable on high notes when we’re singing an ‘ee’ or an ‘ay’ vowel. The ‘y’ at the end of both of those has the tongue heaving up like a breaching whale. There’s no way you’re going to be able to squeeze more air past that whale in your throat.
The fix for this is tongue awareness – and complete devotion to clean, clear target vowels.
Air escaping in the sound. As long as air is leaking out in the tone, sustaining long phrases will be difficult. This is heard as breathiness.
This is an exercise that helps you realize that the voice is more like a combination string/wind instrument than just a wind one.
Sing a phrase.
Take a deep breath – then blow most of it out. Now sing that same phrase again. It should be more focused, and you’ll probably be able to sustain the phrase for almost as long as the previous time when you tanked up on air.
My theory is that the body realizes that you can’t afford to waste any oxygen, so it focuses the sound in order to use less air.
So the two main tricks for being to sing long phrases are very clean target vowels, and focusing the sound.
It’s very nice to have a large lung capacity and strong breathing apparatus musculature – but it’s not essential for singing long phrases.
Here’s the old post about building up breathing capacity.