flute reed
簧 centers on the vibrating reed inside a wind instrument, specifically the thin piece that produces sound in a flute.
簧 combines 竹 (bamboo) with 黄, which likely contributes the sound. The character refers to the bamboo reed used in wind instruments.
The bamboo top 竹 covers the yellow 黄 reed inside a flute. Picture a bamboo flute with a thin yellow reed vibrating to make music.
For コウ, imagine a flute reed made of yellow bamboo that produces a deep 'ko' sound when blown: ko -> コウ.
reed (of a musical instrument)