Audio Basics: What Every Engineer Must Know About Frequency (Hz) and Volume (dB)

In music production and audio engineering, it doesn’t matter how good your analog gear is or how new your plugins are: if you don’t understand what sound actually is, you will never make a clear mix.

This is especially true in a genre like psychedelic trance, which demands a razor-tight low end and meticulous sound design. Here, this knowledge is the foundation of everything.

In this article, we dig deep into the two most important elements shared by both analog and digital (DAW) environments: frequency (Hz) and volume/amplitude (dB).

1. Sound Is a Wave in the Air

Every sound we hear in daily life is a wave, created by air vibrating. To control these waves, audio engineers break them down into two main elements:

• Frequency: determines how high or low a sound is.
• Amplitude: determines how loud a sound is.

Controlling these two elements precisely is the first step in mixing and sound design.

2. What Is Frequency (Hz)?

Frequency (Hz) is the unit that tells us how many times a sound wave completes a full back-and-forth cycle (vibration) in one second. The more vibrations, the higher the sound; the fewer, the lower.

The limits of human hearing

The range of sound the human ear can perceive is generally said to be 20 Hz to 20,000 Hz (20 kHz). In music production, we organize this range of around 20,000 frequencies into several sections:

• Sub-bass (20 Hz – 60 Hz): Deep low end you feel in your body more than hear with your ears. The bottom of a psytrance kick and the core of the bass live here.
• Bass / low end (60 Hz – 250 Hz): Where the foundational energy of a track gathers. If this area gets muddy, the whole track sounds blurred.
• Midrange / mids (250 Hz – 2 kHz): The band most packed with the “real” body of vocals, synth leads and instruments.
• Highs / treble (2 kHz – 20 kHz): The band that controls sparkle, air and how well a sound cuts through.

3. The Essence of Volume and Amplitude (dB)

The unit for loudness is the dB (decibel). The decibel is a slightly unusual unit: 1 dB or 2 dB is not an absolute quantity, but a relative ratio that tells you how far a level is from a reference point.

And the way that reference point is treated is very different in analog gear and in digital (DAW) environments.

The digital reference: dBFS

Inside a DAW (Cubase, Ableton Live, Logic Pro and so on), the reference is 0 dBFS (decibels relative to full scale).

• 0 dB is the absolute ceiling: In the digital world, 0 dB is the ceiling above which no louder sound can be represented.
• A world of negative numbers: That’s why DAW meters always show negative values, such as -6 dB or -12 dB.
• Clipping: If the level goes even slightly above 0 dB, the top of the waveform is chopped off flat, producing harsh, crackling digital noise (digital clipping).

The analog reference: dBu / VU

The world of real analog mixers and compressors is different.

• 0 dB is only a guide: On an analog meter, 0 dB (or 0 VU) is simply the recommended level at which that piece of gear sounds cleanest and best.
• Pleasing distortion (saturation): Analog gear doesn’t break down the instant it goes past 0 dB. Instead, as you push beyond it, the sound gently compresses and gains musical, warm harmonics (distortion).

4. Why You Need to Understand This Difference

Many modern DAW plugins faithfully model legendary analog hardware — SSL-style channel strips and 1176-style compressors, for example.

If you feed these plugins a signal that is right at the top of your DAW’s meter (say, -1 dBFS), the plugin “thinks” it is receiving a signal far louder than the analog original could ever handle. The result is heavy distortion and a muddy sound.

That’s why, even in a digital environment, the analog-era philosophy of gain staging is essential: always pass the signal to the next effect with appropriate level and headroom to spare.

Summary: Your First Step as an Engineer

• Hz (hertz) is pitch. Be aware of the role of each band — lows, mids and highs.
• dB (decibels) is loudness. The digital ceiling is 0 dBFS, and you must never exceed it.
• By applying analog-style level management even in the digital world, you can create dramatically clearer mixes.

In the next article, we’ll look in detail at how to manage these levels inside your DAW, with the technique known as gain staging.