What Does a Dip at 4,000 Hz on Your Audiogram Mean?

A dip in your audiogram around 4,000 Hz, with better hearing at 8,000 Hz on either side of it, is called a noise notch. It’s the classic early sign of hearing damage from loud sound. It often appears before you notice any trouble hearing, because speech depends mostly on lower pitches, which makes it worth catching early: noise damage is permanent, but further damage can be prevented.

This article is general information, not medical advice. An audiologist or doctor should interpret your audiogram.

Why Noise Damages 4,000 Hz First

Hearing at pitches around 3,000 to 6,000 Hz is the most vulnerable to loud sound. Damage shows as thresholds that worsen at 3,000, 4,000, or 6,000 Hz and then recover at 8,000 Hz. Age-related hearing loss, by contrast, usually slopes steadily downwards with rising pitch, with 8,000 Hz the worst.

How It’s Recognised

Coles and colleagues’ guidelines for diagnosing noise-induced hearing loss set three requirements:

1. High-frequency hearing loss.
2. A potentially hazardous amount of noise exposure, at work or in leisure.
3. An identifiable notch or bulge in the audiogram at high frequencies, usually between 3,000 and 6,000 Hz.

Since the notch is only one of the three, a notch alone doesn’t prove noise is the cause, and a single test’s high-frequency results can vary from one test to the next.

What to Do About One

• Protect your hearing from now on. Turn headphones down, wear earplugs at concerts and with loud tools, and take breaks from noise; see How Loud Is Too Loud for Your Ears?
• Retest regularly, such as yearly if you work in noise, and compare each frequency with your earlier tests.
• See a professional for a full assessment if a notch appears or deepens, or if you have ringing in the ears.
• Act fast on sudden loss. A sudden drop in hearing in one ear needs urgent care: the American Academy of Otolaryngology–Head and Neck Surgery’s guideline on sudden hearing loss treats it as needing prompt assessment, since treatment works best early.

Following It in Kaizora

Each ear’s Hearing Threshold at 3,000 Hz, 4,000 Hz, 6,000 Hz, and every other frequency from 250 to 8,000 Hz is its own metric on the Hearing page, from audiograms you log or import from Apple Health. Charting the 4,000 Hz threshold over years shows whether a notch is deepening. Higher values are worse. Your Environmental Sound Level and Headphone Sound Level sit on the same page, so you can see your exposure beside your hearing.

The Short Version

• A noise notch is a dip at 3,000 to 6,000 Hz, usually 4,000, with recovery at 8,000 Hz.
• It’s an early sign of noise damage, often before hearing problems are noticed.
• Protect your ears, retest regularly, and get sudden hearing loss seen urgently.

Sources

• Coles RRA, Lutman ME, Buffin JT, “Guidelines on the diagnosis of noise-induced hearing loss for medicolegal purposes,” Clinical Otolaryngology 25, no. 4 (2000): 264–273. doi:10.1046/j.1365-2273.2000.00368.x
• Chandrasekhar SS et al., “Clinical practice guideline: sudden hearing loss (update),” Otolaryngology–Head and Neck Surgery 161, suppl. 1 (2019). doi:10.1177/0194599819859885
• National Institute for Occupational Safety and Health, Criteria for a Recommended Standard: Occupational Noise Exposure (1998).