What is sample rate?

Sample rate is the number of times per second a digital audio system measures (samples) a sound wave, given in hertz (Hz) or kilohertz (kHz). At 44.1 kHz, the converter takes 44,100 measurements every second.

Why it matters: the Nyquist limit

A sampled signal can only represent frequencies below half its sample rate. That ceiling is called the Nyquist frequency. Anything above it, if it gets into the converter, folds back down as aliasing, which is why converters put an anti-aliasing low-pass filter in front of the sampler, as the sampling article explains.

Human hearing runs roughly 20 Hz to 20 kHz, so a rate a little over 40 kHz is enough to cover it.

Common rates

• 44.1 kHz: the CD rate.
• 48 kHz: the Audio Engineering Society's recommendation for most applications, and common for video.
• 88.2 kHz: used by some professional gear when the destination is CD.
• 96 kHz: recommended by the AES where higher bandwidth or relaxed anti-aliasing filtering is wanted.

These are the rates the sampling article lists as typical for music, along with the AES recommendation.

What streaming services want

Spotify's audio file formats page asks for a sample rate of 44.1 kHz or higher. It says it downsamples higher rates itself, so if you mastered above 44.1 kHz you should not downsample before delivery. Tracks delivered below 44.1 kHz are upconverted and are not eligible for lossless playback.

Sample rate is not bit depth

Sample rate is how often the wave is measured; bit depth is how precisely each measurement is stored. Changing bit depth is where dither comes in.

What we think

Pick one rate at the start of a project and keep it. 48 kHz is a sensible default if anything you make might end up under video; 44.1 kHz is fine for audio-only work. Higher rates cost disk space and CPU, and they do not add anything a listener can hear above 20 kHz. The bigger, more common mistake is mixing rates in one session and letting the DAW resample quietly. Check the rate of every file you import.