Any sound you hear is created by vibration and travels from the source to your ears in the form of waves (which are vibrating particles), these waves bounce off surfaces such as walls to create echoes and tails. If a sound has a low bass frequency it has a long wavelength allowing it to travel through materials easier, this is why if someone is playing music in another room you can hear the bass more than the other parts of the song. Frequency is also relative to to pitch so a high frequency means a high pitch and vice versa.
Sound is measured in decibels (db), when measuring analog sound, 0db is the quietest whereas when you are measuring digital sound then 0db is the loudest, it is important to know the difference between these two when talking about how loud something is. Regular digital audio peaks between -6db and -3db, when recording audio it is important to make sure your audio doesn’t go over 0db as this is the point when it starts to get distorted, maxing out at -3db lowers the chance of your recording going 0db and getting distorted.
acoustics is a branch of physics concerned with the properties of sound and the science that deals with the production, control, transmission, reception and effects of sound. The properties or qualities of a physical space determines how sound is transmitted in that space, for example a big hollow space will have lots of space for the sound waves to bounce off the walls and travel. Diffusion panels are a way of manipulating acoustics in a space, these panels are made with irregular surfaces such as triangles, this splits and disperses the sound, an example is sound proofing foam.