What is it in a niggun that arouses? How does a tune manage to pluck the strings of the heart, elate the soul, transport one to other-world consciousness?
I believe it is because tune is the inner language, the primal tongue of the inner consciousness. When a child first detects the various sounds that surround him, it is first and foremost the rhythm, the taamim, the tone of expression that it picks up; it is this that will then form the basis of all his subsequent learning processes.
Rhythm is in the beat of the heart, the contractions of the lungs, the pulsating energy that dictates light and colour; the entire universe is governed by rhythm.
The holy Arizal writes that there are four main stages in revelation: the highest is ‘taamim’, the lowest is ‘oisyos’ – letters. Tune, or ‘taamim’ [notes] are the highest level of expression, even higher than thought. Lehavdil, the novelist, Viginia Woolf, recognized that ‘rhythm goes far deeper than words’ and actually dictates what words are used and in which order. Rhythm and beat, notes and tunes, are the deeper expressions of human consciousness.
On Shovuos, we read the Asseres HaDibros with the Taam Elyon, which changes the normal setting of the verses into ten recognisable ‘dibros’ – sayings. When we say the tikkun leil shovuos, the Arizal recommends that it is said with the correct cantellation.
At Maamad Har Sinai, one of the main things that are reiterated throughout the event of Revelation, was the Qol HaShofor. The Sound of the Shofar is the fiftieth gate, the stage beyond the counting seven times seven [seven has to do with the various different notes]. This sound started before Bnei Yisroel had assembled at the foot of the mountain, it sounded throughout Matan Torah and continued for some time afterwards [במשוך היובל המה יעלו בהר]. This is the culmination of the Sefiroh, the תספרו חמשים יום. It is the inner Voice that transcends numbers or spatial reality, it is the level of בשנת היובל הזאת תשובו איש אל אחוזתו.
After counting seven times seven, we stand at the foot of Mt. Sinai. Now, we are at that point of realising that G-d is all: He is One and there is nothing else. But reaching that point, we cannot count. We cannot speak. But we can hear the Qol Shofar, the transcendent inner vibration that pulls us close and purifies.
A good Yom Tov.
 Kings II 3.15