Background
Humans hear frequencies from 20 Hz up to 20,000 Hz. The lowest bound, 20 Hz, with a wavelength of nearly 20 meters, is a frequency we feel rather than actually hear. This test helps you benchmark the lowest limit of your audio system's frequency extension.
Because of their increased wavelength (nearly 20 meters at 20 Hz), achieving high output at low frequencies usually requires large drivers (subwoofers). Headphones or earbuds, have less trouble playing back those low frequencies despite their small size: by sealing your ear canal, they create a volume that acts as a pressure chamber. This phenomenon is totally different from what you hear when listening to a speaker playing in the open air. Without the cabin effect — another name for the same phenomenon — earbuds would produce hardly any bass.
A sealed space, or pressure chamber, lifts the low frequencies by 12 dB/octave below a frequency related to the dimensions of the enclosed volume. With an ear canal that is approximately 2 cm long, this magical frequency is located at about 5 kHz. With more than five octaves separating the bass range from this frequency, imagine the bass boost!
The Test File
| 10-200 Hz Sweep + Voice Over |
A -6 dbFS sweeping sine tone, from 10 Hz (supposedly inaudible) to 200 Hz (supposedly played back by all sound systems, including those smallish laptop speakers). On the top of the test tone, a voiceover tells you which frequency is currently playing.
Play back the file until you start hearing the underlying sweeping tone as it rises. The voiceover tells you the frequency you have reached. This frequency more or less represents the lowest limit of your audio system.
Beware of Harmonic Distortion
Frequencies lower than 20 Hz are beyond our frequency hearing range: our low frequency response test - which starts as low as 10 Hz - should remain inaudible until it reaches 20 Hz. If you hear frequencies below 20 Hz, suspect this test to be corrupted by Harmonic Distortion generated from your speaker or subwoofer.
Harmonic distortion can happen at any frequency, but is obvious at frequencies that are supposedly inaudible.
Check your subwoofer for Harmonic Distortion here.
Related pages
Other Subwoofer Tests
- Subwoofer Harmonic Distortion Test
- Subwoofer Transient Response Test
- Design your Custom Sub-Bass Sweeps
- Low Frequency Sound Localization Test
High Frequency Audibility Test
External Links
Help Me Help You!
Is AudioCheck free? Not for me. Your support keeps this site running. Any donation will be rewarded with • uncompressed .wav file download for every test (a download arrow will appear next to each sound icon) • increased durations and sample rates up to 192 kHz in the Tone Gen section • and, best of all, the removal of these pesky payment buttons below 😜
If you already are a patron, please log in.
Frequency Response Tests
Stereo Imaging Tests
Dynamic Range Test
Room Tests
Distortion Tests
