Voicing
Basic idea
Voicing is how the shape of your mouth and throat changes the sound.
What’s involved
Your tongue, throat, and soft palate change the shape and interaction of the spaces inside your mouth, throat, and nose. Those changes affect how the saxophone responds and sounds.
Philosophy
The saxophone isn't the only resonator. Your vocal tract and the saxophone function as one connected acoustic system.
Voicing is much more dynamic than embouchure. I keep my embouchure relatively stable because small changes there can have a large effect on the tonal character of the sound. Voicing changes much more freely and can affect the sound just as much, if not more. That is why you will notice that the Embouchure page frames everything in terms of stability and small changes, while this Voicing page is much more flexible and dynamic.