Nyquist Frequency

In-Depth Explanation

Nyquist frequency is the highest frequency a digital audio system can accurately reproduce. It equals exactly half the sample rate. At 44.1 kHz sample rate, the Nyquist frequency is 22.05 kHz. At 48 kHz, it is 24 kHz. Frequencies above this limit cannot be captured and cause a distortion called aliasing if not filtered out before conversion.

How Nyquist Frequency Works

Digital audio works by taking snapshots of a continuous sound wave at regular intervals. Each snapshot is called a sample. The number of samples taken per second is the sample rate. At 44.1 kHz, the system takes 44,100 snapshots every second.

The Nyquist-Shannon sampling theorem states that to accurately reproduce a frequency, you need at least two samples per cycle of that frequency. One sample catches the peak, and one catches the trough. If a sound wave vibrates at 20 kHz, you need at least 40,000 samples per second to capture it. This is why CDs use 44.1 kHz sample rate. It can reproduce frequencies up to 22.05 kHz, which covers the full range of human hearing (typically 20 Hz to 20 kHz).

If a frequency above the Nyquist limit enters the analog-to-digital converter, the system cannot capture it correctly. Instead of ignoring it, the converter creates a false lower-frequency signal. This is aliasing. A 30 kHz tone recorded at 44.1 kHz sample rate produces a false alias at 14.1 kHz. You hear it as an unpleasant whine that was never in the original sound.

To prevent aliasing, audio interfaces include an anti-aliasing filter. This is a steep low-pass filter placed before the analog-to-digital converter. It removes all frequencies above the Nyquist limit before conversion. At 44.1 kHz, the filter cuts everything above 22.05 kHz. The signal enters the digital domain clean and free of aliasing artifacts.

Higher sample rates push the Nyquist frequency higher. At 96 kHz sample rate, the Nyquist frequency is 48 kHz. The anti-aliasing filter can be gentler because it has more room to roll off. Gentle filters sound more transparent than steep ones, which is one reason some engineers prefer higher sample rates for recording.

Real-World Example

An independent artist records an acoustic guitar at home using a budget audio interface set to 44.1 kHz. The guitar produces harmonics well above 22 kHz. The interface applies its anti-aliasing filter to remove anything above 22.05 kHz before conversion. The recording comes out clean.

Later, the artist adds a distortion plugin to the guitar. Distortion generates new harmonics at very high frequencies. The plugin operates at 44.1 kHz, so its internal Nyquist limit is 22.05 kHz. The new harmonics above 22.05 kHz have nowhere to go. They fold back as aliasing artifacts. The guitar now has a metallic, harsh quality that was not there before.

The artist switches the project to 96 kHz. The Nyquist frequency rises to 48 kHz. The distortion plugin now has room to generate harmonics up to 48 kHz. The aliases that were landing at 14 kHz now land at 52 kHz, which is above human hearing. The guitar sounds smooth and natural.

This is why many producers track at 88.2 or 96 kHz when using distortion, saturation, or aggressive processing. The higher Nyquist frequency gives plugins more headroom to generate harmonics without aliasing. The tradeoff is file size. A 96 kHz project uses twice the storage and CPU of a 48 kHz project. For a 10-song album, that means 20 GB instead of 10 GB of audio files.

Why It Matters for Independent Artists

Understanding the Nyquist frequency helps you make informed decisions about sample rate. Most streaming platforms accept 44.1 or 48 kHz files. If your music does not use heavy distortion or saturation, 44.1 kHz is sufficient. The Nyquist limit of 22.05 kHz covers the entire audible range.

You should consider higher sample rates (88.2, 96, or 192 kHz) when:

• Using distortion plugins: Guitar amp simulators, tape saturation, and bitcrushers generate harmonics that exceed 22 kHz. Higher sample rates prevent these from aliasing into the audible range.
• Pitch shifting: When you pitch audio down, the high frequencies move lower. If those frequencies were aliased, the artifacts move into the most audible range. Recording at 96 kHz before pitching prevents this.
• Time stretching: Similar to pitch shifting, extreme time stretching can expose aliasing artifacts that were previously inaudible.
• Sound design: If you record foley or natural sounds for film or game audio, higher sample rates capture ultrasonic detail that can be pitched and manipulated later.

For most independent artists releasing music on Spotify and Apple Music, 44.1 kHz at 24-bit bit depth is the right choice. It sounds identical to higher sample rates on playback for most material. It saves disk space and CPU power. It matches the delivery format of every major streaming platform.

A practical rule: record at 48 kHz if you work on video content. Video software expects 48 kHz audio. Record at 44.1 kHz if you only release music. Record at 96 kHz only if you use heavy distortion or plan extensive pitch and time manipulation. Read our music production fundamentals for more on sample rates and recording settings.

Related Terms

• Sample Rate - The number of audio snapshots per second that determines the Nyquist frequency
• Aliasing - The distortion that occurs when frequencies exceed the Nyquist limit
• Bit Depth - Determines the dynamic range of each digital sample
• Bitrate - The total data rate of compressed audio, affected by sample rate and bit depth