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Specifications can help you compare products — or confuse you completely. Some numbers are genuinely useful; others are marketing. Below, each spec is explained with what it means, what’s a “good” value, and how much weight to give it.
Frequency response (Hz)
Frequency is pitch, measured in hertz (Hz). Human hearing roughly spans 20 Hz to 20,000 Hz (20 kHz), and the top end falls with age. Frequency response describes which frequencies a device can reproduce and how evenly.
| Range | Frequencies | What you hear |
|---|---|---|
| Sub-bass | 20–60 Hz | Rumble you feel: organ pedals, film explosions, electronic bass |
| Bass | 60–250 Hz | Kick drum, bass guitar, warmth |
| Midrange | 250 Hz–4 kHz | Vocals, guitars, pianos — most musical information |
| Presence | 4–6 kHz | Clarity and articulation; too much sounds harsh |
| Treble / air | 6–20 kHz | Cymbals, sparkle, sense of space |
A range like “40 Hz–20 kHz” is meaningless without a tolerance. “40 Hz–20 kHz ±3 dB” tells you it stays within 3 dB across that range. For speakers and headphones, measured graphs from reviewers are far more informative.
Decibels (dB)
The decibel is a logarithmic unit used for loudness, gain and ratios. Key rules of thumb:
- +1 dB: a just-noticeable difference for many listeners.
- +3 dB: twice the power, a clearly audible step.
- +6 dB: twice the sound pressure (voltage).
- +10 dB: sounds roughly twice as loud and needs ten times the power.
dB SPL measures sound pressure level: a quiet room is around 30 dB SPL, conversation around 60 dB, and prolonged exposure above about 85 dB can damage hearing.
Impedance (Ω, ohms)
Impedance is the electrical resistance a speaker or headphone presents to an amplifier (varying with frequency). Speakers are commonly rated at 4, 6 or 8 Ω. Lower impedance draws more current, so your amplifier must be rated for it.
Headphones range from about 16 Ω (IEMs, portable headphones) to 300–600 Ω (some studio and audiophile models). High-impedance headphones need more voltage, which phones may not supply.
Sensitivity and efficiency
Sensitivity says how loud a speaker plays for a given input — usually dB SPL at 1 watt (or 2.83 V) at 1 metre. A speaker rated 90 dB plays twice as loud in power terms as one rated 87 dB. For headphones, it’s given in dB/mW or dB/V.
| Speaker sensitivity | Meaning |
|---|---|
| Below 85 dB | Low — needs a powerful amplifier |
| 85–89 dB | Average — most bookshelf speakers |
| 90–94 dB | Easy to drive |
| 95 dB and above | Very efficient — suits low-power and tube amps (e.g. horn speakers) |
Power (watts)
Amplifier power should be quoted as continuous (RMS) power per channel, into a stated impedance, across 20 Hz–20 kHz, at a stated distortion (e.g. “50 W per channel into 8 Ω, 20 Hz–20 kHz, 0.05% THD, both channels driven”). “Peak”, “max” or “PMPO” numbers are inflated and can’t be compared.
Speaker power ratings describe how much power a speaker can handle, not how much it needs. Read how much power you need.
Distortion and noise
- THD (Total Harmonic Distortion): unwanted harmonics added to the signal, as a percentage. Modern electronics are usually far below 0.1%; speakers and headphones have much higher distortion, especially in the bass.
- THD+N: distortion plus noise.
- SNR (Signal-to-Noise Ratio): how far the signal is above background hiss, in dB. Higher is better; 90 dB+ is very good for most electronics.
- Dynamic range: the span from the quietest to the loudest signal a device can handle.
- Crosstalk / channel separation: how much of one channel leaks into the other.
Digital specs: bit depth, sample rate, bitrate
- Sample rate (kHz): samples per second. 44.1 kHz (CD), 48 kHz (video), up to 192 kHz or more in hi-res.
- Bit depth: precision of each sample. 16-bit ≈ 96 dB dynamic range; 24-bit is standard for recording.
- Bitrate (kbps): data per second. CD is 1,411 kbps uncompressed; lossy streams are often 128–320 kbps.
More detail in our DACs & streaming guide.
Understanding the EQ (equaliser)
An EQ boosts or cuts specific frequency ranges. Most headphone apps, streaming apps, receivers and DAWs include one.
Cut before you boost
Reducing an annoying frequency often sounds more natural than boosting others, and avoids distortion.
Make small changes
2–3 dB is usually enough. Large boosts eat amplifier headroom and can cause clipping.
Know the bands
Too boomy? Cut around 100–250 Hz. Harsh? Try 2–5 kHz. Dull? A gentle lift above 8 kHz.
Use one EQ at a time
Stacking EQs in the app, OS and headphones makes problems hard to find.
Graphic EQs have fixed bands (sliders). Parametric EQs let you set frequency, gain and width (Q) — more precise and used for headphone correction profiles.
Receiver and soundbar settings
| Setting | What it does | Good starting point |
|---|---|---|
| Speaker size (Small/Large) | Whether a speaker gets full-range bass or bass is redirected to the sub | “Small” for all speakers when you have a sub |
| Crossover | Frequency below which bass goes to the subwoofer | 80 Hz (THX standard); higher for small satellites |
| Distance / delay | Aligns arrival time from each speaker | Set by room correction or measure with a tape |
| Channel levels | Balances loudness of each speaker | Set by room correction or an SPL meter app |
| Sub phase (0°/180°) | Aligns sub timing with main speakers | Choose whichever gives fuller bass at the seat |
| LPF for LFE | Upper limit for the film’s bass channel | 120 Hz |
| Dynamic range compression / Night mode | Reduces the gap between loud and quiet | On for late night, off for full cinema impact |
| Dynamic EQ / Loudness | Adds bass and treble at low volume to compensate for hearing sensitivity | On for casual low-volume listening |
| Room correction | Measures the room with a mic and corrects response problems | Run it, then fine-tune by ear |
Subwoofer controls
- Gain / level: start low and increase until bass blends, not dominates.
- Low-pass filter: set to LFE/bypass when using a receiver’s crossover; set it manually (e.g. where your speakers roll off) when using a stereo amp.
- Phase: flip between 0° and 180° (or use a variable dial) while sitting in your seat; keep the setting with the fullest bass.
- Auto on / standby: turns the sub on when a signal arrives.
Headphone and Bluetooth settings
- ANC levels / adaptive ANC: adjusts noise cancelling to surroundings.
- Transparency / ambient: lets outside sound in.
- Codec selection: on Android, choose AAC, aptX or LDAC in developer settings; LDAC has quality/stability modes.
- Spatial audio / head tracking: virtual surround that can make films and some music more immersive.
- Multipoint: connects to two devices at once (e.g. phone and laptop).
- Low-latency / game mode: reduces delay for video and gaming.
Frequently asked questions
Which spec matters most for speakers?
No single number. Measured frequency response (on- and off-axis), sensitivity and impedance together tell you most of what matters — plus how they sound in your room.
Is lower impedance better for headphones?
Not better, just easier to drive from phones and laptops. High-impedance headphones can sound excellent with an appropriate amplifier.
Should I use the loudness button?
At low volumes, yes if you enjoy it — it compensates for the ear’s reduced sensitivity to bass and treble at low levels. Turn it off at normal or high volume.