Why macOS Resamples Your Audio

The Core Audio Problem

macOS uses Core Audio as its system-wide audio engine. This is great for compatibility — any app can play audio without worrying about hardware details. But it creates a problem for audiophiles.

Core Audio forces all audio streams through a mixer that operates at a single, fixed sample rate. If your system is set to 44.1kHz and you play a 96kHz file, macOS will resample it down to 44.1kHz before sending it to your DAC.

What Resampling Actually Does

Sample rate conversion (SRC) is a mathematical process that creates new samples from existing ones. Even with high-quality algorithms, this process:

• Introduces mathematical artifacts
• Can affect timing precision
• Removes the "bit-perfect" guarantee
• Defeats the purpose of Hi-Res audio

Why Apple Does This

Apple's design prioritizes simplicity and compatibility. By standardizing on one sample rate:

• Multiple apps can play audio simultaneously
• System sounds always work
• No sample rate switching delays
• Better compatibility with all audio hardware

For most users, this is fine. For audiophiles with expensive DACs and lossless music, it's a dealbreaker.

How to Check If You're Being Resampled

Look at your DAC's display while playing music:

• Playing a 96kHz track but DAC shows 44.1kHz? → Resampled
• Playing a 48kHz track but DAC shows 44.1kHz? → Resampled
• Every track shows the same sample rate? → Definitely resampled

The Solution: Match Sample Rates

To bypass resampling, your system sample rate must match the track's native format. You can do this manually in Audio MIDI Setup, but you'd need to change it for every different sample rate in your library.

Key Takeaways

• macOS resamples all audio to one sample rate by design
• This affects every audio app, including Apple Music
• Your Hi-Res tracks are being downsampled without you knowing
• The only fix is matching sample rates before playback