We hear this expression from voice teachers all the time. What does it really mean, and how does a singer "open" their throat? First of all it's true that when the vocal tract is free from constriction and therefore open the singer creates a resonant sound. I liken this variation in resonance of the closed versus open throat to taking a guitar and stuffing its body with rags. If you strum the guitar it loses its sound and the strumming becomes muffled. If you remove the rags you hear the beautiful sound of the guitar strings resonating. We function in the same way. When our throat is "closed" or constricted our sound is muffled. When our throat is open we hear the splendor of our voices. No pushing or forcing of our voice is needed to sound good. In fact, pushing only closes the singer's throat more.
I think of the throat in 3 dimensions and this helps the student understand what an open throat really is. Like any physical structure the throat (which is basically the vocal tract and larynx) has three dimensions. It opens in a vertical, horizontal and front to back space.
The vertical space, also known as the "low larynx", happens in two ways. When we breathe in a relaxed abdomen (think belly) and pelvic floor (think bathroom muscles) the larynx gently goes down. This doesn't happen with a clavicular breath. This is also known as a tracheal pull. The other way to effect the vertical laryngeal position is tonal concept. If we think of making a deep sound (such as Yogi bear, Julia Child, or an opera type of sound) the larynx positions itself lower. This happens on an unconscious level depending on what type of music we are singing. If we think of a pop or broadway belty type of song we will sing with a higher larynx, typically at the height we use for normal speech. A low larynx opens the throat more in a vertical sence than a low one, but both types are legitimate ways of using the voice and are used for different styles. A larynx that is too high due to constriction will result in a tight and strained sound. Low breathing will set a good laryngeal position no matter what the style.
The horizontal space (which is the space around the vocal cords themselves) is not as often thought about but is of vital importance. Called by Estill teachers as "retraction" it is needed for all styles of singing. It is the space in your throat created by the silent inhale and exhale. Try breathing through your mouth silently and exhaling silently as well. Now try a noisy inhale-exhale and you can feel the difference.
The third dimension is the one of depth. This rarely taught concept has personally transformed my voice as well as the voices of my students. Breathe through your mouth and feel cool air going down the back of your tongue and down into your throat as if there was a space you could sense between the back of your tongue and your cervical spine. This is a channel for your sound. Perhaps one you never thought of.
If you can feel the spaciousness created by a silent breath in the last two dimensions (horizontal and front to back), as well as keep your breath going into a relaxed low body space for the low larynx dimension, you will be singing with an open throat. We set up the conditions of the open throat with each breath we take as singers. Talk about "inspiring"!