If listening to music, an 80W hi-fi amplifier and a pair of 8-inch bookshelf speakers are very suitable for a 20-square-meter room. If you want to watch a big movie, you need to buy a dual-channel decoding amplifier with DTS, 5, 1 and power 100W, with a pair of 6,5-inch Yaling speakers in front of the main speaker and a 6,5-inch center speaker in the back.