Three Ways to Describe Sound in Words

"Frequency, Amplitude, Waveform"

The most frustrating moment in sound work is when you don't like the result but can't articulate what the problem is.

While operating the VARCO Sound beta, I've noticed a clear difference in user feedback. Some write, "The sound is a bit strange," while others say, "The low end is lacking weight and the high frequencies are piercing, causing ear pain." The latter reaches the desired result more quickly in the next attempt. When you can pinpoint the problem accurately, the solution becomes precise as well.

This article aims to create that language. The necessary physics knowledge is less than you might think.

The Nature of Sound

Sound is a pressure wave that travels through the air as a result of the vibration of an object. When the diaphragm of a speaker moves back and forth, it compresses and rarefies the air, and when this wave shakes the eardrum, we perceive it as sound.

The graph of this wave is called a waveform. It's the wavy line you see in editing tools. There are two pieces of information you can read from it.

How to read Frequency and Amplitude from a waveform

Frequency, the Pitch of Sound

Frequency indicates how many times a wave repeats in one second, measured in Hz. The higher the frequency, the higher the sound; the lower the frequency, the lower the sound.

The range of human hearing is approximately 20Hz to 20,000Hz. In practice, this range is divided into three zones. Most of the conversation in sound work revolves around these three words, so it's good to keep this part clear.

• Low (20~250Hz) · The heaviness felt in the body. The impact of an explosion, the low rumble of a dungeon.
• Mid (250Hz~4kHz) · The place where the presence of sound lives. Dialogue, footsteps, and most of the body of impact sounds.
• High (4~20kHz) · Sparkle and clarity. The sound of metal collisions and the sparkle of magical effects.

For example, if a boss appearance scene feels flat, it usually means there's a lack of Low. Conversely, if multiple sounds overlap during a battle and it just sounds noisy, it's likely that sounds are crowding in the Mid, obscuring each other. Knowing this allows you to make actionable judgments like, "I need to reinforce the Low and tidy up the Mid" instead of just saying, "It's just not good."

The same goes for when you're disappointed with the results generated by VARCO Sound. If you can identify which range is the problem, you can change the prompt from "make it heavier" to something more specific like "make it a heavy low end." You can also determine which track among the results needs adjustment.

Amplitude, the Volume of Sound

Amplitude indicates how much the wave oscillates. In practice, the unit used is dB (decibels).

There are two important things to know. dB is a logarithmic unit, so an increase of 6dB roughly doubles the signal size. Additionally, in digital audio, 0dBFS is the ceiling. Exceeding this causes the top of the waveform to be clipped, resulting in distortion (Clipping). Be careful when layering multiple tracks; it’s common for each to be fine individually but to exceed the limit when combined.

The Four Basic Waveforms

Synthesizers create sounds starting from a few basic waveforms. Knowing the characteristics of each makes the third part easier.

1. Sine Wave: The purest sound with no harmonics.
2. Sawtooth Wave: A bright, piercing sound that includes all harmonics.
3. Square Wave: Contains only odd harmonics, giving a hollow retro game console feel.
4. Triangle Wave: A slightly brighter, mellow sound than Sine. It fits well with 8-bit style melodies.

The Secret of Harmonics and Timbre

Even if two sounds have the same pitch, a piano and a violin sound completely different. What creates that difference is harmonics.

Almost all sounds in the world are a combination of a fundamental frequency and its integer multiples. The mixture of harmonics determines the timbre. The difference between the sound of metal and wood, or a monster's roar, lies in the composition of harmonics. Sound design is closely related to sculpting these harmonics.

A Taste of Envelope

Sound grows and diminishes over time. The sound of a sword clashing bursts and disappears in an instant, while the ambiance of a dungeon gradually rises. This temporal change is called Envelope. The difference between impactful sound effects and dreamy background sounds mostly lies here. We'll cover the concept of ADSR in the third part.

Frequently Asked Questions (FAQ)

Q. What is the difference between Hz and dB?
Hz measures pitch, while dB measures volume. They are units measuring different properties.

Q. Is a sample rate like 44.1kHz also a frequency?
The units are the same, but the meanings are different. Sample rate refers to how many times sound is measured in one second when recording digitally. To reproduce the original sound, it must be measured at more than twice the audible limit.

Q. Do I need monitor speakers to make accurate judgments?
It’s nice to have them, but they are not essential. What’s important is to listen in various environments. Game sounds are played back in different environments like headphones, laptop speakers, and TVs.

You Need to Train Your Ear for Frequency Sensation

Try creating "a low rumbling explosion" and "a sharp metal clash" in VARCO Sound and listen to them alternately. You'll understand the difference between Low and High much faster than just reading about it.

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