Digital Aliasing Sound Test

Background

Aliasing

Consider a digital audio system and a steadily rising sine wave tone.

At lower frequency, the tone is sampled with many points per cycle. As the tone rises in frequency, the cycles get shorter and fewer points are available to describe it.

At half the sampling rate, only two samples are available per cycle. We are at the limit stated by Nyquist. Still, those two samples are sufficient to reconstruct the original signal.

If the tone keeps on rising, the number of points per cycle becomes inadequate to represent the signal. Those samples will be misinterpreted by the digital-to-analog converter and will be associated with a wrong frequency. This phenomenon is referred to as aliasing.

The Test Files

Aliasing Check
44.1kHz Sample Rate

After the three beep tones, a -3 dbFS sweeping sine tone from 22 kHz (half the sampling rate at 44.1kHz) down to 1 kHz.

As the test starts by playing frequencies that are probably beyond your audible range, you won't hear anything for a moment, except the three starting beep tones. When the frequency under test reaches your audible range, a high pitched sine tone will be heard, steadily decreasing down to 1 kHz.

If your hear anything different, your sound system likely suffers from (severe) aliasing. In this test, aliasing will appear as frequencies increasing instead of decreasing.

To check whether aliasing is genertated by your browser's audio plug-in or your sound card, download the original file (click the download arrow) and play the test tone straight from your hard disk through your favorite audio application.
Alternate test
48kHz Sample Rate

Alternatively, you can try the 48 kHz version of this test. Beware: all other test files available on this site are 44.1 kHz.

Related pages

Other Aliasing Tests

External Links

Help Me Help You!

Is AudioCheck free? Not for me. Your support keeps this site running and growing without ads. Every donation gets rewarded with an access to • uncompressed .wav files downloads, for every test • sample rates up to 192 kHz, in the tone generator section • a suggestion box, on every page • no ads, never.

PayPal - The safer, easier way to pay online!
EU ← living in the EU?

If you already are a patron, please log in.


Ads will disappear with 3 visitors contributing today. Still missing 2...

My Recommendation

If you are looking for pretty nice headphones, here is my favorite in terms of 'best value for the money' : the HD668b. If money is not an issue, try the HD600.

My Other Websites

HearingTest​.online myNoise.net
Check out your hearing online, with this serious test!Audiophile-quality noises and soundtracks for every day use!