The Miteler Rebbe's Kapelya
This soulful niggun is attributed to the Mitteler Rebbe. In addition to his many talents, the Mitteler Rebbe inherited from his father (the Alter Rebbe, Rabbi Shneur Zalman, the first Chabad Rebbe) a great love for sacred music and Chassidic melody. His father had composed ten soul-stirring melodies, and the Mitteler Rebbe knew their powerful effect to rouse the singers and listeners to great heights of ecstasy and attachment to G‑d. He encouraged the singing of these and other melodies of his own composition at certain occasions of solemn and joyous gatherings. He even had an organized choir from among his Chassidim who led in the singing, called the Kapelya.
The Tzemach Tzedek explained that the purpose of the orchestra which played on certain occasions for his father-in-law, the Mitteler Rebbe, was to prevent him from reaching the state of termination of earthly existence (klos hanefesh). In his supreme service to the A-lmighty, the Rebbe could have literally expired unto G‑dliness.
This niggun Kapelya, one of the musical compositions of his choir by that name, is divided into four sections, symbolizing the four rungs on the ladder of approach and devotion of man to G‑dliness.