Audio Sample Rate - BrowserTrace Deep Dive

1. Technical Classification

Web Audio API JavaScript Client-Side Hardware Attribute

Audio sample rate detection uses the Web Audio API to query your system's default audio sampling frequency. This value:

Reflects Hardware: Determined by audio device and driver settings
Easily Readable: Simple AudioContext.sampleRate property access
Rarely Changes: Stable unless audio settings or devices change
Limited Values: Typically 44100 Hz or 48000 Hz on most systems

2. Background & Purpose

Sample rate represents how many times per second audio is sampled for digital processing. Understanding sample rates is fundamental to digital audio.

What Is Sample Rate?

Sample rate (measured in Hertz/Hz) is the number of audio samples captured or played per second:

Higher = Better Quality: More samples capture more detail
Nyquist Theorem: Sample rate must be 2x highest frequency to capture
Human Hearing: 20 Hz to 20,000 Hz (20 kHz)
44100 Hz Standard: Captures up to 22,050 Hz (above human hearing)

How Browsers Access Sample Rate

const audioContext = new AudioContext();
const sampleRate = audioContext.sampleRate;
// Returns: 44100, 48000, 96000, etc.

The browser reports the default sample rate of your system's audio output device.

Historical Context

44100 Hz: CD Audio standard (1980s), still very common
48000 Hz: Professional video/audio standard (1980s+)
96000 Hz+: High-resolution audio (audiophile equipment)

3. Common Sample Rate Values

Sample Rate	Common Usage	What It Suggests
44100 Hz	CD Audio, Consumer Hardware	Standard consumer audio setup, most common
48000 Hz	Professional Video/Audio, Modern Devices	Professional equipment or newer consumer devices
96000 Hz	High-Resolution Audio	Audiophile equipment, professional audio interface
192000 Hz	Studio Recording	High-end professional audio production equipment
22050 Hz	Low-Quality Audio	Old hardware or budget devices (rare)
8000 Hz	Telephony	VoIP or telephony equipment (very rare in browsers)

Most Common: Over 90% of users will report either 44100 Hz or 48000 Hz. Unusual sample rates are relatively rare and more identifying.

4. Legitimate Uses

Web Audio Applications

Audio Playback: Ensuring audio plays at correct rate
Audio Recording: Web apps that record audio need to know sample rate
Real-Time Processing: Audio effects, filters, synthesis need correct timing
Game Audio: Synchronizing sound effects and music
Music Production: Browser-based DAWs and audio tools

Quality Adaptation

Streaming Services: Adapting audio quality to device capabilities
VoIP Applications: Optimizing voice call quality
Video Conferencing: Matching audio to device settings

Fingerprinting Component

While legitimate uses exist, sample rate is also collected as part of device fingerprinting:

Device Identification: Combined with other attributes for tracking
Hardware Profiling: Identifying audio equipment type
Bot Detection: Unusual values may indicate automated browsers

5. Platform & Hardware Differences

Default Sample Rates by Platform

Windows

Typical: 48000 Hz (Windows 10/11 default)

Alternative: 44100 Hz on some systems or with older hardware

Configurable: Users can change in Sound Control Panel

macOS

Typical: 48000 Hz (macOS default for most Macs)

Alternative: 44100 Hz on some models or configurations

Configurable: Changed via Audio MIDI Setup utility

Linux

Typical: 44100 Hz or 48000 Hz depending on distribution

Highly Variable: Depends on audio server (ALSA, PulseAudio, PipeWire)

User-Configurable: Often customized by users

Mobile Devices

iOS: Typically 48000 Hz

Android: Usually 48000 Hz, sometimes 44100 Hz

Limited Configuration: Users rarely change mobile audio settings

Professional Audio Equipment

Users with external audio interfaces or professional equipment may report higher sample rates:

96000 Hz: Common in mid-range audio interfaces
192000 Hz: High-end recording interfaces
Identifies Professionals: Musicians, producers, audio engineers

6. Privacy Implications & Tracking Risks

Privacy Risk: MEDIUM

While sample rate alone is not highly unique (most users have 44100 or 48000 Hz), it contributes to device fingerprinting when combined with other attributes.

Limited Uniqueness

Sample rate has relatively few possible values:

44100 Hz: ~50% of users
48000 Hz: ~45% of users
Other rates: ~5% of users

Alone, this doesn't uniquely identify you, but it narrows the pool.

When Sample Rate Becomes More Identifying

Unusual Sample Rates

If you have 96000 Hz or higher, you're in a much smaller group. This immediately identifies you as someone with professional audio equipment, which is valuable demographic information for advertisers.

Combined Fingerprinting

Sample rate is combined with canvas fingerprints, fonts, screen resolution, etc. The combination of all these attributes creates a unique identifier.

What Sample Rate Reveals

Audio Hardware Type: Consumer vs. professional equipment
Potential Profession: High sample rates suggest audio/music professionals
OS Configuration: Default or customized audio settings
Device Age: Older devices more likely to use 44100 Hz

Tracking Persistence

Stable: Sample rate rarely changes unless you change audio settings or devices
Cross-Browser: Same sample rate reported across all browsers
Incognito Ineffective: Private browsing shows same sample rate

7. Protection & Control

Limited Control Options

Sample rate is a fundamental audio property that's difficult to spoof or hide without breaking web audio functionality.

Browser Privacy Features

Tor Browser

Method: May standardize or block sample rate detection

Effectiveness: High - but may affect audio functionality

Firefox privacy.resistFingerprinting

Method: May standardize reported sample rate

Enable: about:config → privacy.resistFingerprinting = true

Effectiveness: Moderate

Brave Browser

Method: Fingerprinting protection may affect sample rate reporting

Effectiveness: Moderate with strict shields

System-Level Changes

Change Audio Settings: Adjust sample rate in OS audio settings
Windows: Sound Control Panel → Device Properties → Advanced
macOS: Applications → Utilities → Audio MIDI Setup
Linux: PulseAudio or ALSA configuration files

Practical Advice: Changing sample rate is impractical for most users and may affect audio quality. Instead, focus on comprehensive fingerprinting protection through privacy-focused browsers like Brave or Firefox with enhanced protections.

What Doesn't Work

Incognito Mode: Reports same sample rate
VPN: Changes IP but not audio settings
Clearing Cookies: No effect on hardware properties
Ad Blockers: Don't prevent sample rate detection

8. Learn More

BrowserLeaks Audio Test Test your audio fingerprint including sample rate MDN - AudioContext.sampleRate Technical documentation of sample rate property Wikipedia - Audio Sampling Understanding sample rates and digital audio Wikipedia - 44,100 Hz History and explanation of the CD audio standard EFF Cover Your Tracks Test your browser's overall fingerprint Firefox Anti-Fingerprinting How Firefox protects against fingerprinting Brave's Fingerprinting Protection Brave's approach to blocking fingerprinting MDN - Web Audio API Complete Web Audio API documentation

Your Audio Sample Rate