Question: What genre of music  did Loudest Whisper debut on a vinyl record format characterized by a speed of 33 ⁄ rpm, a 12 or 10 inch (30 or 25 cm) diameter, and use of the "microgroove" groove specification?
Sentence (from "The Children of Lir (Loudest Whisper album)"): The album was released on LP record in Ireland by Polydor Records in 1974 in a limited edition of 500 copies.
Relevant evidence: Yes