At home, the space is small, the sound is reflected, it will enhance the volume. In the square, the space is large, the sound did not meet obstacles, there is no reflection, so it sounds small.
Enhancing the sound volume with an amplifier is one way to do it, and in addition, the treble spreads over a large length and not wide enough. And bass propagation length is small, the width is large, so in the square, try to adjust the volume of the amplifier to the low-frequency sound, the effect will be better.