What Are Acoustics? Everything You Need to Know

Posted December 10, 2021 by in Lifestyle

If you’ve ever recorded or been to a live music performance, you’ve seen acoustics at play. But what does the term “acoustics” actually mean? 

In audio recording environments, acoustics is everything. That’s why professionals use anything that can improve the outcome, from acoustic felt panels to completely soundproofing a room during construction, there are many different ways to manipulate the acoustics of a given room. 

Continue reading to learn more about what acoustics is and how you can use it to treat your recording environment for the best possible outcome. 

Room Acoustics

Acoustics is the branch of physics that studies the science of how sound behaves. You can associate anything that humans or animals can hear with acoustics and musicians primarily use acoustics to study the audible range of sound. When discussing a sound’s behavior, scientists primarily focus on the sound wave’s ability to reflect in a given space. The way the sound wave behaves will alter the sound someone hears. 

What Is the Difference Between Acoustics and Audio?

To better understand acoustics, you should also understand the difference between acoustics and sound. Acoustics is the study of sound in a mechanical form, whether it be in air or some other medium. In the recording industry, the term audio refers to an electrical representation of an acoustic signal. Audio is a convenient way to transmit, manipulate, and store sounds but no one can hear audio waves unless they are translated into acoustic signals. 

Whenever we hear a sound, we are hearing acoustic waves, whether electronics were involved in the path from the source to our ears or not. 

How Do You Acoustically Treat a Room?

Every room has different acoustic properties you need to consider when trying to cultivate the sound you desire most. Two basic properties govern acoustics most: absorption and diffusion. Absorption refers to treating rooms with materials that have sound absorption properties. These materials can include foam, acoustic felt, heavy blankets, and rigid mineral-wool.

Because high-frequency noises travel faster and at shorter distances than low-frequencies, absorption works most effectively on high-frequency sounds by reducing flutter echoes. You can use sound absorption to reduce bright sounds in performance halls, practice rooms, and recording studios. On the other hand, low frequency is challenging to absorb because sound waves are much longer and conventional absorption isn’t as effective. For low-frequency sounds, bass traps work most effectively. 

Diffusion works differently than absorption, helping control the energy in a room and providing sound quality in the middle and high-range spectrum frequencies. Diffusion works using multi-faceted surfaces to scatter sound waves. The most common materials for diffusion are plastic, polystyrene, and wood. You can also use these materials for other acoustical treatments. 

Where Do You Place Absorption and Diffusion Technology?

Ideally, your room should take acoustical treatment into account. Unfortunately, that’s not always the case. Having a room composed with the same materials throughout, and incorporating a  unique design that accounts for attenuation is a strategic advantage for anyone trying to treat their room. 

That said, you don’t need a perfect room to achieve the sound you’re looking for. When trying to improve your sound within your room, you should try to use a couple beneficial sound measurement tools such as a sound meter, dosimeters, and octave band analyzers. 

To better understand acoustics, it’s helpful to familiarize yourself with the following terms: 

  • Amplitude: The size of sound vibrations. Amplitude is primarily responsible for determining the loudness of your sound. 
  • Frequency: The sound vibration’s speed that is measured in Hz and determines the sound’s pitch. 
  • Fullness: Refers to the amplitude of the reverb pertaining to the initial sound. 
  • Clarity: Refers to the sound achieved by reduced amplitude. 
  • Liveness: refers to a room with a long reverb time. Thus, a live room has long reverb times. 
  • Deadness: refers to rooms having a short reverb time. When your room is dead, it means you have a short reverb time. 
  • Intimacy: Rooms that deliver the first reverb to listeners within 20 milliseconds of the direct sound have intimacy. This has the result of listeners feeling closer to the performer. 
  • Warmth: Warmth is also referred to as brilliance and it describes the reverb time at low frequencies relative to higher frequencies. 
  • Texture: Texture is the interval of time between direct sound and the first reverberations it causes. The first five reflections need to reach the listener within 60 milliseconds for the noise to have a good texture.
  • Blend: The blend refers to the mixture of all sound performers and its uniform distribution to listeners. In live performances, the blend often requires reflectors to help properly distribute the sounds.

Outdoor Acoustics 

As you move away from a source of sound, it gets quieter. The same is true of virtually any energy wave. Whether it be light or radio waves, the intensity of energy is highest when it is closest to its source. Distance is the most important factor when calculating acoustics outdoors.

However, unless you are in a massive field or out at sea on an open boat, sound can run into things, so you need to consider acoustics when setting up outdoor recording.

Reflection

When sound comes into contact with other objects, some of it reflects. It behaves like light in this sense. The angle of incidence equals the angle of reflection. Large, flat surfaces act as mirrors for sound and bounce it back to its source. 

Absorption

Most materials absorb some sound. Any sound not reflected gets absorbed in some manner. It may be converted to heat or other forms of energy as it passes through a material. Absorption is frequency dependent and the balance between the amounts of absorbed and reflected sound vary substantially from low frequencies to high frequencies. 

Diffusion 

If the reflecting surface is not flat and smooth, the sound can reflect in different directions at once. The uneven surface produces several smaller surfaces that have different incidence angles, which result in varying angles of reflection. Diffuse surfaces are often used in architectural acoustics to eliminate or reduce the presence of distracting echoes.

Acoustics describe the properties of sound and how sound waves behave in varying environments. For practical applications, acoustics are most often used when trying to treat recording environments to achieve the highest quality sound possible.