購買擴音機

Go to Mongkok MTR Bank Centre Exit. There is quite a number of AV shops in the building on the left (the one with Body Shop on the G/F). But be careful when you buy. Make sure you carry away, make sure that you see the goods and test it before you pay.

For speakers, not sure of the quality of your speakers. But I would say you better use the Celestian as the front speakers for better sound reproduction, especially for music.