The "1st house" and "2nd house" in flute refer to the structure of the wind instrument. The flute is made from a section of wood with openings and sound holes at each end. There is a metal tube in the middle of the wood, which is divided into two parts: the treble tube and the bass tube.

- The 1 house (also called the soprano) is the longer part of the flute, which includes the mouthpiece and the first, second, third, fourth, fifth and sixth keys. This part is used to produce the high register of the flute.

- The 2-chamber (also called the bassoon) is the shorter part of the flute, which contains the seventh, eighth, and ninth keys as well as the basso key. This part is used to produce the bass range of the flute.

When playing, wind instruments produce sound by blowing in the breath and causing it to vibrate. The dividing point between House 1 and House 2 is the key combinations, but they are actually the same instrument, just with different key combinations and breath control to produce different pitches.