An audiogram is a graph that plots your hearing sensitivity as frequency in Hertz against intensity in decibels, giving you a snapshot of how softly you can detect pitches from low rumbles to high consonants. After about twenty minutes in a sound booth, you walk out with a single page that documents the quietest tone you can hear at each pitch, for each ear, on a standardized scale. That page is what an audiogram shows: your hearing thresholds compared to normal, plotted so a clinician can spot patterns in seconds.
This walkthrough breaks down every mark on the page, from the frequency axis to the speech banana, so anyone holding their first hearing test results can spot what matters.
The Anatomy of an Audiogram Chart
An audiogram looks like a grid tilted on its side, and the grid carries more meaning than most first-time patients realize. Two axes do all the work: one tracks pitch, the other tracks loudness, and the symbols scattered across the grid tell the rest of the story.
The Horizontal Line: Frequency in Hertz
Frequency runs along the bottom of the chart from 125 Hz on the left to 8000 Hz on the right, measured in hertz (cycles per second). Lower pitches sit on the left, higher pitches on the right. A bass drum thump lives near 125 Hz, a baby’s cry sits closer to 4000 Hz, and the sibilance of the letter “s” lands somewhere around 6000 Hz. The axis uses a compressed scale so the speech-relevant frequencies (500 to 4000 Hz) get the most space.
The Vertical Line: Intensity in Decibels
Intensity drops down the left side of the chart from –10 dB HL at the top to 120 dB HL near the bottom. Quieter sounds sit higher on the chart, louder sounds lower. A whispered conversation lands around 30 dB HL, normal speech around 50 dB HL, and a chainsaw at close range pushes past 100 dB HL. The reference scale, dB HL (decibels hearing level), is calibrated to average young adult hearing so zero represents the threshold a healthy ear can just barely detect.
| Component | Position on Chart | What It Measures |
|---|---|---|
| Frequency (Hz) | Horizontal axis | Pitch from low (125) to high (8000) |
| Intensity (dB HL) | Vertical axis | Loudness from quiet (–10) to loud (120) |
| Right ear symbols | Across the grid | Air conduction thresholds, right side |
| Left ear symbols | Across the grid | Air conduction thresholds, left side |
Why Calibration Standards Matter
Calibration to ANSI S3.21 or ISO 8253 standards keeps the chart consistent from clinic to clinic, which means an audiogram produced in Ohio compares cleanly with one taken in Oregon. The FDA regulates audiometric equipment under 21 CFR Part 801.427, requiring calibration tolerances tight enough that a 25 dB HL tone in one booth sounds like a 25 dB HL tone in another. Without that baseline, two charts from two offices would describe the same ear in two different languages.
Decoding the Symbols and Lines on the Chart
The symbols are the shorthand that lets an audiologist read your chart in a glance. Each one points to a specific measurement made during the test, and together they draw a picture of how sound travels through your ear.
Air Conduction Symbols
A circle marks each right-ear air-conduction threshold and an X marks each left-ear one, representing tones delivered through headphones that travel the full ear. When you sit in the booth and raise your hand each time you hear a beep, the clinician marks the softest level you respond to at each pitch. A connected line of Os or Xs across frequencies shows how your hearing shifts from low to high, often sloping downward when high pitches get harder to detect.
Bone Conduction Symbols
Brackets or angled lines () indicate bone conduction responses, the tones sent through a small vibrator placed behind the ear that bypass the outer and middle ear entirely. Comparing air conduction symbols to bone conduction symbols reveals where a blockage lives. If air conduction shows a 40 dB threshold but bone conduction shows a 10 dB threshold at the same pitch, the gap points to a conductive problem in the ear canal or middle ear rather than damage to the inner ear or nerve.
Arrows and Unmeasured Points
Arrows pointing off the edge of the chart signal that a threshold was beyond the equipment limits rather than normal hearing. If the audiometer could not produce a tone loud enough for you to hear at a given pitch, the symbol rides the edge with an arrow showing direction. A rightward arrow on a 120 dB symbol at 1000 Hz means your ear could not detect the loudest tone the machine delivers, which carries different implications than a quiet, normal threshold.
Tip: ask for a legend key printed on your audiogram. Most clinics include a small reference box, and matching the symbols on your chart to that key takes the guesswork out of self-reading.
Where Normal Hearing Falls on the Graph
ASHA defines normal hearing as thresholds between 0 and 25 dB HL across all tested frequencies. When every symbol lands at or above the 25 dB line, your hearing is functionally healthy. Anything below that line on the chart indicates some degree of hearing loss.
The Shape of a Normal Audiogram
Thresholds clustered near the top of the chart at every frequency define a normal audiogram, with air and bone symbols sitting close together. Symmetry between the two ears and a smooth, gently rising pattern across the frequencies suggests healthy auditory function from the outer ear to the auditory nerve. A single dip at one frequency can still reflect noise exposure, aging, or early otosclerosis even when the rest of your thresholds look fine.
What Counts as a Deviation
Understanding the normal range makes any deviation immediately visible. A threshold of 30 dB at 4000 Hz in one ear while the other ear sits at 15 dB tells a clear story: the affected ear struggles with the pitch where consonants like “s,” “t,” and “k” live, even though low-pitched vowels remain easy. The WHO uses a similar classification framework, defining disabling hearing loss in adults as a threshold above 40 dB HL in the better ear for frequencies at 1, 2, and 4 kHz.
Those thresholds matter because they determine which everyday sounds fall inside or outside the range your ear can actually detect.
| Threshold (dB HL) | Classification | Everyday Impact |
|---|---|---|
| 0–25 | Normal | No difficulty in typical settings |
| 26–40 | Mild loss | Trouble with soft speech or distant conversation |
| 41–55 | Moderate loss | Misses parts of normal conversation without amplification |
| 56–70 | Moderately severe | Speech must be loud; group settings become difficult |
| 71–90 | Severe loss | Hears only amplified sound; relies heavily on visual cues |
| 91+ | Profound loss | Limited access to sound even with powerful devices |
The Speech Banana and Everyday Sounds
The speech banana is the banana-shaped overlay that sits across the middle of the audiogram, marking the frequency and intensity range covered by typical conversational speech. Plotting your thresholds against this shape shows at a glance which sounds of spoken language slip out of reach.
Vowels and Consonants in Different Zones
Vowels cluster in the lower, louder portion of the speech banana, around 250 to 1000 Hz at 40 to 60 dB HL. Consonants sit higher and softer, around 2000 to 6000 Hz at 20 to 40 dB HL. When your hearing loss dips into the consonant zone but leaves vowels untouched, you can hear that someone is talking without catching the words, the classic “I can hear but can’t understand” complaint that so many patients describe to their audiologist.
What Patterns Outside the Banana Predict
Loss above 2000 Hz predicts difficulty hearing consonants and clarity rather than volume, which is why a spouse’s mumbling across the dinner table is often the first symptom you may notice. The NIDCD reports that roughly 25 percent of adults between 65 and 74 have disabling hearing loss, and high-frequency loss is the most common age-related pattern. A slope that drops sharply above 2000 Hz is the visual signature of this pattern.
Tip: ask the audiologist to circle your thresholds directly on a speech banana printout. Seeing your results inside that shape turns abstract decibels into sounds you actually miss: doorbells, birdsong, grandchildren’s voices.
Reading Patterns for Type and Severity of Loss
Symbol placement tells you more than severity; it points to the underlying cause. Two patterns account for most audiograms a clinician sees, and learning to spot them turns the chart from a puzzle into a roadmap.
Sensorineural Loss: Air and Bone Match
Overlapping air and bone conduction thresholds signal sensorineural hearing loss, a type rooted in the cochlea or auditory nerve. Aging, noise exposure, genetics, and certain medications all target this pathway. Because both air and bone conduction land at similar thresholds, the symbols cluster together, often sloping downward toward the high frequencies.
Conductive and Mixed Loss: The Air–Bone Gap
Air conduction thresholds sitting noticeably lower than bone conduction create the air–bone gap that points to conductive or mixed loss. Fluid behind the eardrum, cerumen impaction, otitis media, or otosclerosis can create this pattern. Bone conduction bypasses the blockage, so thresholds measured by vibrator look better than thresholds measured by headphones. A mixed loss shows both an air–bone gap and thresholds beyond the normal range, pointing to problems in more than one part of the ear.
Classification by Degree
Six degrees,mild (26–40 dB), moderate, moderately severe, severe, and profound,set the scale clinicians use to frame urgency and next steps. High-frequency loss is the most common age-related pattern and is often the first sign you notice, sometimes years before a full diagnostic workup. The pure tone average (PTA), calculated from your thresholds at 500, 1000, and 2000 Hz, gives a single number that summarizes your everyday hearing ability and helps track change over time.
A single number is useful for tracking, yet it cannot tell you which conversations you struggle with or what to do next.
| Pattern | Symbol Relationship | Likely Cause |
|---|---|---|
| Sensorineural | Air and bone symbols overlap | Inner ear or auditory nerve damage |
| Conductive | Air symbols below bone symbols, both within normal range or near | Outer or middle ear blockage |
| Mixed | Air below bone, with both below normal | Combined inner ear and outer/middle ear issues |
| High-frequency slope | Thresholds drop above 2000 Hz | Aging or noise exposure |
Turning the Chart Into Real-World Decisions
An audiogram is a starting point, not an ending. The decisions that follow depend on reading the chart well, asking the right questions, and tracking changes over time.
How to Use the Audiogram at Follow-Up Visits
Slip the printed audiogram into your folder before each follow-up so the visit pivots around the chart instead of memory. Ask the audiologist to mark your results inside the speech banana so the affected consonants are visible, then ask which communication strategies address that specific pattern. A chart that shows a steep high-frequency drop calls for different solutions than a flat moderate loss across all pitches, and the right conversation flows from the symbols you can both see.
Matching Loss to Solutions
Use the degree and configuration of your loss to compare device styles, assistive listening tools, or referrals to an ENT. Mild high-frequency loss often responds well to receiver-in-canal devices tuned to amplify the 2000 to 6000 Hz region. Conductive loss with a clear air–bone gap may benefit from medical treatment rather than amplification, which is why the ASHA referral pathway points patients to a physician when the gap exceeds 15 dB at multiple frequencies.
Tracking Change Over Time
Recheck periodically because hearing thresholds shift slowly, and a baseline audiogram makes future change measurable. Noise exposure, cardiovascular health, certain medications, and aging each leave fingerprints on the chart. A second audiogram two or three years later reveals whether your thresholds have drifted, stayed flat, or improved after treatment. That longitudinal view turns a one-time snapshot into a tool for protecting the hearing you still have.
- Request a printed copy of every audiogram and file it in your personal health folder.
- Ask the clinician to circle affected zones on the speech banana overlay.
- Note the date and any changes in medication or noise exposure between tests.
- Compare new audiograms against the baseline using the same symbol legend.
- Bring a partner or family member to the appointment so they can hear the explanation alongside you.
FAQ
What does an audiogram show about your hearing?
A graph of frequency versus intensity plots the softest detectable sound at each pitch for each ear on the audiogram. It also distinguishes between air conduction (sound traveling through the whole ear) and bone conduction (sound bypassing the outer and middle ear) so the type of hearing loss can be identified.
How do you read an audiogram chart?
Start at the bottom of the chart and read pitch from left (low) to right (high), then move up to read loudness from soft (top) to loud (bottom). Find the symbols for your right ear (circles) and left ear (X marks), then trace how they sit relative to the 25 dB line and the speech banana overlay.
What is the normal range on an audiogram?
Zero to 25 dB HL across every tested frequency defines the ASHA-cited normal range on an audiogram. Thresholds at or above the 25 dB line indicate hearing within normal limits, while anything below that line signals some degree of hearing loss.
Can an audiogram detect the type of hearing loss?
Yes. Comparing air conduction symbols to bone conduction symbols reveals whether your loss is sensorineural, conductive, or mixed. An air–bone gap of 15 dB or more at multiple frequencies points to a conductive or mixed component, while overlapping symbols point to sensorineural loss.
What do the symbols on an audiogram mean?
Circles mark the right ear and X marks the left ear for air conduction. Brackets or angled lines indicate bone conduction thresholds, and arrows pointing off the chart signal that the threshold exceeded the equipment’s loudest output rather than showing normal hearing.
How accurate is an audiogram hearing test?
Audiometry is considered highly reliable when performed in a calibrated sound booth by a trained clinician, with test–retest reliability within 5 dB at most frequencies. Accuracy depends on your responsiveness, equipment calibration to ANSI or ISO standards, and a quiet testing environment.
