Decibel Shield
FAQ › Glossary
Hertz vs decibels: pitch and level
Hertz counts how many times a sound wave vibrates each second, which we hear as pitch: 100 Hz is a low hum, 4,000 Hz is a shrill whistle. Decibels measure the level of the wave, which we hear as loudness. They are independent, so there is no conversion between them; a sound has both a frequency and a level, the way a colour has both a hue and a brightness.
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Why people try to convert them
The ear is not equally sensitive at every pitch. A 100 Hz tone and a 1,000 Hz tone at the same decibel level do not sound equally loud; the low one seems quieter. That is why A-weighting exists, and why a hearing test reports a separate decibel threshold at each frequency. The relationship is a curve, not a formula that turns one unit into the other.
| Hertz (Hz) | Decibels (dB) | |
|---|---|---|
| Measures | Frequency: vibrations per second | Level: pressure relative to 20 µPa |
| Heard as | Pitch | Loudness |
| Human range | About 20 Hz to 20,000 Hz, shrinking at the top with age | 0 dB (threshold) to about 120 dB (pain) |
| Speech | Mostly 250 to 4,000 Hz | About 60 dB at conversational distance |
| On an audiogram | The horizontal axis, 250 to 8,000 Hz | The vertical axis, hearing level in dB HL |
Sources: NIDCD, Noise-Induced Hearing Loss; NIOSH, Noise and Hearing Loss.
Test both
The hearing age test sweeps frequency upward to find the highest pitch you can hear, and the online hearing test plots your threshold in decibels at each frequency, which is the audiogram. The speaker test tones page plays single frequencies so you can hear what a hertz value sounds like.
Can you convert hertz to decibels?
No. Hertz is frequency and decibels are level; a sound has one of each. Asking for the decibels of 440 Hz is like asking for the brightness of the colour red. Equal-loudness curves describe how loud a given level sounds at each frequency, which is the closest thing to a link between them.
What frequency is most damaging to hearing?
Damage depends on level and duration more than pitch, but noise-induced hearing loss typically appears first as a notch around 4,000 Hz on the audiogram, because the ear canal resonance boosts that region.
What is dB HL on a hearing test?
Hearing level: decibels relative to the average threshold of young adults with normal hearing at each frequency, so 0 dB HL is normal at every pitch. It is a different reference from dB SPL, which is why audiogram numbers cannot be compared directly to a decibel meter reading.
What is the highest frequency a person can hear?
Around 20,000 Hz in childhood, falling steadily with age; many adults over 50 hear little above 12,000 Hz. The hearing age test estimates where your own ceiling sits.