We make vocal sound by allowing breath from our lungs to set the vocal folds into vibration, creating a small, buzzy sound. We shape that into what we (and others) hear as our voice. There’s lots of reasons to relax into this.
If there’s any tightness or rigidity in the muscles of the larynx, the vocal chords can’t vibrate easily, limiting the range of motion (and pitch). If the muscles are tight, then you’re locked into a shape, losing control over timbre and tone. The voice sounds pushed, strained and strident.
In singing, if a voice is locked with tension, you can’t make a smooth transition from chest voice to head voice. That’s the “break” that you hear so much about. The vocal chords actually change shape to go from a slower to faster vibration rate. If you’re pushing your “belt” voice up, there’s a point where the vocal chords go into a short spasm to break out of the locked position into the higher range. It’s not a pleasant sound.
The goal is to let the breath do the work. Relax the throat. Allow the vocal chords to respond to the air flow.
This ain’t football practice. A little more push or force will not make it better. It will only work against you. Imagine a pianist or guitarist tightening up the muscles in their hands and then trying to play. There’s no flexibility or control. You need to be loose and supple. The same with your voice.
Work with your voice, not against it. Remember, we’re a wind (breath) instrument, not a muscle instrument. My vocal mantra is:
Take the breath low
Relax the throat
Let the voice float
Let go of push and strain in your voice. Your voice will sound richer, project farther, and create a much more effective impression. Push and strain will only hurt your voice and make you sound weak.