Dense solids.
Related Information:
Sound waves travel mechanically, by transferring their energy, molecule by molecule, through a transfer medium. So, the more dense the transfer medium (molecules closer to one another), the faster sound energy is transferred.
Different perspective:
Sound travels by vibrating the particles of the medium through which it travels. So sound travels best in steel as the particles are tightly packed, through wood or water but poorly in air, and not at all in a vacuum.
water
Denser material, higher speed.
Spongy materials are the most difficult for sound to travel through. Vacuum is the best acoustic insulation but it doesn't really count for the purpose of this question, since it is not a material but a lack of material.
Surprisingly no. Air is a gas which means that the molecules are far apart. Even a liquid is better that air for sound to travel through because the molecules are closer together. But, a solid is the best for a sound to travel through. This is because the molecules are very close together so the vibration is transferred much quicker though the material.
The best type of material that conducts sound the best would be any solid. Only because of the sound that hit the compacted atoms and it would travel the fastest.
It travels best through solids
Copper.
solid
It travels best through solids
Sound waves travel best through air than anything else.
the matter inside is bunched together so sound travels best through a solid.
liquids.
sound waves travel through best through solids because they are more dense, then liquids, and finally they travel the worst through gasses.