Ether is the highest element, and is nearest to us, for it surrounds us and is within us.

The sound of ether is self-contained, and it holds all forms and colors. It is the base of all sounds, and is the undertone which is ever continuous. Its instrument is the human body, because it can be audible through it. Although it is all pervading, yet it is unheard. It manifests to man as he purifies his body from material properties. The body can become its proper instrument when the space within is opened, when all the tubes and veins in it are free. Then the sound which exists eternally in space becomes manifest inwardly also. Ecstasy, illumination, restfulness, fearlessness, rapture, joy and revelation are the effects of this sound. (Hazrat Inayat Khan)

Quote from the Omananda website (elementals)