On Shabbat Beshalah (Exodus 13:17- 17:16), also called Shabbat Shira, we read the Song of the Sea (Shirat Hayam). Therefore, AJAM, the maqam known for its joyous and happy melodies, is applied according to ALL sources.  The melody of Maqam AJAM is familiar to many, because it is the Arabic equivalent to the Western Major scale. Excluding the Yom Tob festivals, this is one of only three Shabbats of the year that this maqam is applied. HAZZANUT: Shirat Hayam in Zemirot recited in unison. PIZMON SEFER TORAH: Rahum Ata (page 216).