Jaw, Tongue, Lips and Soft Palate

The jaw hangs from the skull at the temporomandibular joint just in front of each ear. Opening is a rotation plus a slight forward glide; the right feeling is that the jaw 'drops' and slightly back, not that it juts forward. Open vowels need about two fingers' width between the teeth, but not by lifting the chin: the head stays level, the jaw falls. A clenched or protruded jaw tightens the muscles under the chin, which are attached to the hyoid and therefore to the larynx.

The tongue is the biggest and most flexible part of the filter. Its root is the front wall of the throat; its body defines the shape of the mouth. Two numbers describe a vowel: how high the tongue is (F1) and how far forward (F2). The problem is that the tongue is rooted in the same bone that carries the larynx — the hyoid — so if the tongue pulls back and bunches up (tongue-root tension) the larynx goes up and back with it and the throat narrows. The rule of thumb: a singing tongue is wide and soft, with the tip lightly touching the lower front teeth on most vowels, and the area under the chin soft when you press it.

The lips are the end of the tube. Protruding and rounding them can lengthen the tube by more than a centimetre and lower all formants — useful for darkening and for helping to keep the larynx low; spreading them shortens the tube and brightens the tone. On high notes a small rounding of the lips (and modifying the vowel toward 'o' or 'u') often relieves the pressure that makes the larynx climb; at the same time over-pouting is another kind of tension, so look for a balanced, forward but easy shape.

The soft palate (velum) opens or closes the way to the nose. Raised, it seals the nasal cavity and the sound goes out through the mouth; lowered, the nasal cavity becomes a side branch which adds extra resonances and anti-resonances (nasal vowels, 'm', 'n', 'ng'). A raised, slightly arched velum is the usual aim in Western singing, which feels like the beginning of a yawn or an 'inner smile'. A simple test: sing a vowel and pinch the nose; the sound should not change if the velum is closed. Do not overdo it: a rigidly lifted palate is also tension.