Can be heard. If you sing loudly in the middle of the night, you can hear it no matter upstairs or downstairs. The sound is circuitous and can spread through the cracks in doors and windows. The sound does not expand in a certain direction, but spreads in all directions. If the doors and windows are not tightly sealed, you can hear loud singing. In addition, in the newly built buildings nowadays, the floors are low, the floor slabs and partition walls are too thin, and the sound can even It will spread everywhere through vibrations.

Can be heard. If you sing loudly in the middle of the night, you can hear it no matter upstairs or downstairs. The sound is circuitous and can spread through the cracks in doors and windows. The sound does not expand in a certain direction, but spreads in all directions. If the doors and windows are not tightly sealed, you can hear loud singing. In addition, in the newly built buildings nowadays, the floors are low, the floor slabs and partition walls are too thin, and the sound can even It will spread everywhere through vibrations.