Hayedeh (Persian: هایده) or Ma'soumeh Dadehbala (Persian: معصومه دده بالا), (April 10, 1942, Tehran, Iran – January 20, 1990, San Francisco) was a Persian classical and Pop singer with a contralto vocal range. In a career spanning more than 20 years, she had many hits. More than two decades after her death, Hayedeh is considered one of the most influential and iconic Persian vocalists recognized as one of the most popular 20th century singers. Hayedeh was born in Tehran. She is the older sister of another famous Persian singer, Mahasti. Hayedeh's professional career began in 1968 at the age of twenty six as a singer on a Persian traditional music Tehran Radio program called "Golhaa-yeh Rangarang" (Colorful Flowers)( گلهای رنگارنگ) directed by Davoud Pirnia. Hayedeh studied Avaz (Persian vocal music) with the famous Persian violinist and composer Ali Tajvidi. Hayedeh performed her first hit song "Azadeh" which was composed by Tajvidi on the lyrics of Rahi Mo'ayeri. Performing this work with Golha Orchestra in 1968 at Radio Tehran introduced Hayedeh's vocal talent to Persians who warmly received it. "Azadeh" which was composed by music by Ali Tajvidi, and was written by Rahi Moayeri was Hayedeh's first official hit. It was first performed in 1968 on Radio Tehran with the Gol-ha Orchestra and was later released by Ahang-e Rooz Records. In the 1970s Hayedah added Persian pop music to her Persian classical repertoire. In this period Hayedeh worked with several songwriters, such as Fereydoun Khoshnoud, Jahanbakhsh Pazouki, Anoushiravan Rohani and Mohamad Heydari. "Bezan Tar", "Gole Sang", "Norooz Amad", "Eyde To, Eyde Man" and "Soghati" were among her memorable works during this period.
Hayedeh's albums are ageless masterpieces and are still best sellers. Her songs are constantly played on Persian TV and radio channels. Many covers of her songs are sung by famous Persian pop singers. According to Prof. Erik Nakhjavani in Encyclopædia Iranica: "Analogues to Delkash, before her, Hayedeh sang with technical authority and passionate energy. Her laryngeal control made it possible for her to produce a series of graceful vibrato and glissando vocalizations required by the Avaz Persian vocal music. She could smoothly pass from the upper reaches of her alto voice to the lower, fuller, and darker range of the contralto. This mixture of strong laryngeal strength and learned vocal technique gave her alto-contralto voice a rare, powerful resonance and texture in the performance of the Avaz. Furthermore an acute sense for musical timing, the rhythmic flow of vocal music, affective musical phrasing, and poetic delivery enabled her to express and interpret effectively any songs she sang."