Sound needs molecules bumping molecules to transfer the momentum and energy. There are no molecules in a vacuum. Defend your answer. Water and steel are much faster carries of sound than air. Low frequencies of sound are emitted by larger objects.
Larger objects have more inertia than smaller objects and therefore take more energy to vibrate.
Once vibrating though, they have a greater ability to transmit the energy through more air and are heard farther away than a smaller, higher horn. Distinguish between forced vibrations and resonance. Forced vibrations are ones caused on objects whose natural frequencies are not the same as the source object's frequency. It takes more energy to start a non-natural frequency than one that is natural. The emitted frequency can start the receiving object vibrating with a minimum of input energy.