The Plain-English Guide to Audio Specs: Impedance, Frequency Response, and SNR

Why Audio Specs Feel So Confusing

Walk through any headphone or speaker listing and you'll encounter a wall of numbers: 32Ω, 20Hz–20kHz, 110dB SNR. Manufacturers publish these figures because they describe real, measurable properties — but the labels are rarely explained. This guide translates the three specifications that appear most often into plain terms, so you can read a spec sheet with genuine understanding rather than guesswork.

If you've already worked through our smartphone spec field guide, you'll find the same decoding approach applied here to audio gear.

Impedance: How Hard Is the Driver to Drive?

Impedance (measured in ohms, Ω) describes the electrical resistance a headphone or speaker presents to an audio source. The higher the impedance, the more voltage is required to push adequate volume through the driver.

Consumer headphones typically range from about 16Ω to 600Ω. Earbuds and wireless headphones tend to cluster at the low end — 16Ω to 32Ω — because they're designed to run directly from a phone or tablet, which delivers limited voltage. Studio and audiophile headphones often start at 80Ω or higher and benefit from a dedicated headphone amplifier to reach their designed performance level.

A practical rule of thumb: if a headphone's impedance is 50Ω or above, check whether your source can drive it properly. Running high-impedance headphones from an underpowered source typically results in lower volume, reduced bass, and a thinner overall sound — not a flaw in the headphone itself, but a mismatch in the system.

Frequency Response: What Range of Sound Can It Reproduce?

Frequency response states the range of audio frequencies — from low bass to high treble — that a driver can reproduce, measured in hertz (Hz) and kilohertz (kHz). Human hearing generally spans 20Hz to 20kHz, so most consumer audio products list this range as their baseline.

The range figure alone tells you relatively little. What matters more is how flat the response is across that range — meaning how evenly the device reproduces all frequencies without boosting or cutting some more than others. A product that claims 20Hz–20kHz but rolls off steeply below 60Hz or above 15kHz may still produce bass and treble, just at noticeably lower volume.

Manufacturers rarely publish the full frequency response graph in a marketing listing, but independent audio measurement databases and review sites often do. A flatter curve generally indicates more accurate, neutral reproduction; a deliberately shaped curve may boost bass or cut harsh highs as a consumer preference tuning choice. Neither is inherently better — it depends on what you're listening to and whether you prefer accuracy or a particular sonic character.

Signal-to-Noise Ratio: How Much Hiss Is in the Signal?

Signal-to-Noise Ratio (SNR) measures the gap between a device's intended audio output and its background noise floor, expressed in decibels (dB). A higher SNR means the useful audio signal is much louder than any unwanted hiss, static, or electronic noise.

For consumer audio equipment — DACs (digital-to-analog converters), amplifiers, and wireless headphone electronics — an SNR of 90dB or above is generally considered adequate. Higher-end equipment commonly reaches 110dB to 120dB or more. In practice, most listeners cannot perceive noise at all when SNR exceeds about 95dB under normal listening conditions.

SNR becomes more noticeable at the extremes: very quiet passages in classical music, late-night low-volume listening, or in-ear monitors with high sensitivity. If you primarily listen at moderate volumes to music with consistent levels, SNR differences between 95dB and 110dB are unlikely to be audible in most environments.

For a parallel look at how display and connectivity specs work in consumer electronics, see our TV spec glossary.