觀無量壽佛經義疏 3.6

3.6

「『又有樂器懸處虛空，如天寶幢，不鼓自鳴。』」如寶幢者，言其量也。四、樂音說法。

"‘There are also musical instruments suspended in empty space, like heavenly jeweled banners, which play by themselves without being struck.’" "Like jeweled banners" speaks of their size. Fourth, the musical sounds expounding the Dharma.