Music in the Baha'i Temples (Yes or No?)

Bahāʾ-Allāh urges the recital and the melodious chanting of scripture in the Mašreq al-Aḏkār, especially by children and especially at dawn (Ketāb-e Aqdas, vv. 115-16, 150, pp. 110-11, 143-44; tr., pp. 61, 74). With regard to saying prayers at dawn, he states that this could be done anytime from dawn until two hours after sunrise (Ketāb-e Aqdas, p. 47; tr., p. 111). In writing to the prominent Iranian musician and Bahai, Mirzā ʿAbd-Allāh Farāhāni (ca. 1843-1918, see ʿABDALLĀH, MIRZĀ), ʿAbd-al-Bahāʾ encourages music in the Mašreq al-Aḏkār (Māzandarāni, Amr va Ḵalq, III, p. 364, tr. Compilation of Compilations, II, p. 76). Shoghi Effendi has stated that there should be no musical instruments used, only a capella singing by live singers (not recorded). The words sung should be from the Bahai or other scriptures (Shoghi Effendi, 1982, pp. 607-8).

https://iranicaonline.org/articles/mashreq-adkar