Understanding the Science of Sound: A Beginner’s Guide to Acoustics

Sounds bombard us from every direction in the modern world. It doesn’t matter if we’re in our homes, offices, or sitting in traffic halfway between the two. Even when we’re enjoying some serenity deep in nature, sound is all around us. Whether we perceive those sounds as pleasant or painful depends largely upon the pitch, volume, and other characteristics of the sound.

Through careful control, we can ensure that most of the sounds we hear at home and work are pleasant ones. A little knowledge of acoustics basics can go a long way toward creating soundscapes that calm our minds rather than stress us out. Let’s look at what we mean when we talk about acoustics, as well as how to use the key concepts to create more pleasant places in our lives.

Acoustics Basics: How Sound Waves Work

The first step in designing an acoustic plan for your indoor or outdoor space is understanding the basic way sound waves work. It all comes down to some simple physics principles and learning how to use them to perfect the sound in your space. Let’s begin with acoustics basics.

What is Sound?

Anyone who isn’t deaf understands what we mean by the term sound, but many of us don’t know exactly what it is or how the human ear and sound perception works. 

Sound is simply vibrational energy that travels through some medium (air, water, walls, etc.) and eventually reaches our eardrums. Once that vibrational energy reaches our ears, it vibrates those eardrums, which our brains pick up via the auditory nerve and interpret as sound.

Sources of sound can include anything that produces vibrations. The specifics of the source dictate things like pitch, frequency, and volume, and ultimately create a sonic experience that is unique to that source. This is why we can differentiate between percussive instruments, stringed instruments, and wind instruments, simply by hearing the sound they create.

What are Pitch, Frequency and Volume?

If you’ve ever taken music lessons or participated in your school’s choir, you’ve undoubtedly heard of pitch. This is a means of expressing the subjective way we perceive the sound of different rates of vibration, or frequency. 

All sounds travel at a specific frequency. A sound wave’s frequency is determined by the number of vibrations that repeat over a predetermined unit of time. In sound measurement, frequency is measured in Hertz (Hz), which represents the number of vibrations per second. 

When that frequency is very low, we hear a low pitch. When that frequency is very high, we hear a high pitch.

The strength of sound vibrations is expressed as volume. The more powerful those vibrations, the louder they sound. Both high and low pitches can become a real nuisance at high volumes or when prolonged over time, which is the reason we implement acoustical measures to minimize the impact of acoustics on communication and focus in the spaces where we spend the bulk of our lives. 

What is Acoustics?

Acoustics is the physics branch that deals with the way mechanical waves pass through gasses, liquids and solids. As it pertains to design, this includes understanding the way sound waves move through space and reflect off of surfaces, as well as designing indoor and outdoor spaces that are primed to absorb and reflect waves to help eliminate acoustical issues.

How Acoustics Affect Our Lives

Understanding the science of sound and acoustics basics isn’t limited to scientists and those in the music industry. There are very practical uses for this knowledge in our everyday lives. We may already understand the importance of acoustics in home theaters and recording studios, but proper acoustics are also essential parts of controlling noise distractions in offices and making our homes more peaceful places.

Acoustics Basics: Common Acoustical Issues

Acoustical issues are more common in spaces that share a certain set of traits. Rooms with lots of hard surfaces, high ceilings, and a lack of materials to counter the effects of those hard surfaces and high ceilings will usually suffer from the most prominent acoustical issues. There are a couple of incredibly common acoustical issues that we regularly deal with in untreated spaces: echo and reverberation.

What is Echo?

The first acoustical issue that people commonly experience is echo. Nearly all of us are familiar with the concept, but many people are surprised to learn that even miniscule amounts of echo in indoor spaces can create communication issues. 

Echo is caused by sound waves traveling through space, slapping against a reflective surface, and returning to the source. The simplest way to eliminate echo is to introduce soft and absorptive materials to the reflective surface, giving it more absorbency. This allows a portion of the sound waves that strike those otherwise reflective surfaces to get absorbed, preventing them from returning back into the room. 

What is Reverberation?

Reverberation, or reverb, is another common acoustical issue, and is closely related to echo. When sound waves reflect off of floors, walls, and ceilings, they will continue to ping pong around the room until something absorbs them. As they gather in the space, these sounds actually become louder and more disruptive.

Adding materials that absorb and diffuse sound waves is a great way to combat potential issues, but remember that balance is key. A space that is too absorptive will still experience acoustical issues that make communication difficult by leaving the room sounding overly quiet. 

Acoustics Basics: Treating Rooms for Better Sound

Now that we understand some acoustics basics, we can dive into the world of acoustical treatments. This is not the same thing as soundproofing, which involves stopping sound passage between one space and another. Acoustical treatments involve removing sounds inside the space, creating a better atmosphere for concentrating, communicating, and relaxing.

For a proper acoustical treatment, we must take the sound properties of the offending noises into account to successfully remove them from the equation. That’s because we treat high frequencies a little differently from low ones. Let’s look at some easy ways to improve the acoustics of your space.

Add Materials for Sound Reflection and Absorption

The basis for acoustical treatment centers around sound reflection and absorption. Since echo and reverberation are created through reflections that bounce back and forth across a space, the main ways we combat them is by absorbing and redirecting sound waves at prominent reflection points. We use a handful of common tools to accomplish this. 

Acoustic Panels

One product that is regularly used in the acoustic treatment of indoor and outdoor spaces is the acoustic panels. They come in all shapes and sizes, but the main purpose of acoustic panels is to absorb sounds in the middle to high frequency ranges through their dense, porous construction, and convert the vibrational energy of sound waves into heat energy through a process called sound damping.

Acoustic panels are most effective when placed in areas where direct sound reflections could result in echo and reverberation, and ultimately, excess noise. This means that if the main source of sound in the space is human speech, panels placed on walls in the range of 3-6 feet above the floor will deliver the best results. If a set of speakers in a music studio is the main source of sound, panels placed at the same level as those speakers will be most effective in creating a good acoustic environment for music studios.

Bass Traps

For lower frequencies that are not well handled by standard acoustic panels, bass traps may be required to tackle the issues they create. Bass traps are generally placed in the corners of rooms, where bass waves tend to build up and amplify. There are different types of bass traps available, and they are divided into two general groups: porous absorbers and resonant absorbers.

Porous Absorbers

The cheaper and easier to use of the two options is the porous absorber. This type of bass trap works in largely the same way as acoustic panels. They are made of dense, porous materials that help absorb some of the lower frequencies. Unlike traditional acoustic panels, both types of bass traps work best when placed a distance from the wall, rather than right up against it.

Resonant Absorbers

Resonant absorbers are able to better remove bass waves from rooms, but the way they do so makes construction and usage more difficult, which can represent a barrier to entry for some people. One trait that makes them so desirable is that they can be tuned to tackle specific trouble frequencies. This makes them more effective in a narrow range, but less effective outside that range.

Sound Diffusion

One of the most effective ways to redirect sound waves is to place sound diffusers at reflection points. Diffusers are available in a number of different shapes and sizes, but each type serves the same basic purpose. That purpose is to redirect sound waves and eliminate the back and forth that causes the acoustical issues that increase the volume of the noise in the space.

Treating Your Own Spaces

Understanding sound and acoustics basics is a necessary first step toward creating better sounding spaces in our homes and offices, but more in depth knowledge is required to get the results we’re after. The simplest way to properly treat any indoor space is to work with professionals. We have the products and experience to help you get the biggest bang for your buck, and can save you loads of wasted time. If you’re ready to take your media room to the next level or host more lively dinner parties without all the noise, reach out for a consultation.