Music has the unique ability to establish or alter the mood of the listener. The music of Jewish prayer is no different in that respect. Weekday services have their own mode and style, ranging all the way to the once-yearly nusach (musical arrangement) for Ne'ilat Sha'arim (Closing of the Gates) at the conclusion of Yom Kippur.
What does this have to do with the season of t'shuvah specifically?
The music of the Yamim Noraim (High Holidays, Days of Awe, or Ten Days of Repentance) is obviously unique to those days as well as extraordinarily beautiful. From the opening notes on Rosh Hashana eve, continuing through the previously mentioned ne'ilah, the drama and gravity of the days are established. Among others, at this time of year I find myself humming the familiar melody of the chatzi kaddish that marks the entrance to the hallowed hours of the mussaf (additional) services for Rosh Hashana and Yom Kippur, among other melodies. Allowing those sometimes chilling notes to escape my lips moves me into a mindset where I am instantaneously closer to God, a central feature of the t'shuva season.
To understand the power of the nusach, and the place it has in prayer makes us better daveners. On the side bar, I have listed a website entitled Virtual Cantor. If you have a moment, locate the recordings for the High Holidays, you will likely find familiar sounds. Allow yourself to be consumed by the power of nusach