Is ke chakkar me mat pado. 12 inch speaker ke liye bahut bada output transformer lagate hain. Transformer ki cost pure amplifier ke cost se jyada hoga. Gaan PA amplifier ke liye hi dedicated sound output transformer use karte hain. Horn speaker, chunga ke liye. Uska kaam alag hai, 1 km 500 meter door door tak same quality maintain hota hai, awaz dabta nahin hai.