How to read an FR graph without getting misled

Every product page on this site draws the same chart. Up the side is how loud each sound plays; along the bottom is pitch, running from the deepest bass (20 Hz) to the highest sparkle (20,000 Hz). That chart is the frequency response: a picture of what the headphone does to every pitch you feed it¹. It is the most useful single measurement a headphone will ever give you - and the most misread. Here is how to read one honestly.

The line is not flat, and it should not be

People expect a flat line - every pitch played at the same loudness - to be "correct". For speakers that is true, because a speaker plays sound across the room first and your ears shape it on the way in. A headphone fires straight into your ear canal, and the canal itself boosts some pitches - by as much as 10 dB (decibels, the loudness unit every audio chart counts in). So a good headphone is drawn flat only on a chart that has been adjusted for your ear first¹². If a chart shows wild hills and you cannot see a target line on it, trust those hills a little less.

The target line is the ruler, not the verdict

Serious charts draw a target line: the shape most people prefer. The best-known one is Harman's target, built from big listening studies - roughly two-thirds of tested listeners picked it as their favourite sound³⁴. Two honest caveats. One: "two-thirds" means a real minority prefers something different, and that is allowed. Two: the target is a preference map, not physics. A curve hugging the line reads as balanced; a curve deliberately above it in the bass is tuned for bass lovers. The graph tells you which one you are looking at - not which one you must enjoy.

On this site every chart says whether the curve is measured (recorded by a real lab setup) or an estimate (a labelled best guess at how the product is voiced at the factory, judging by its close relatives, replaced the day a real measurement arrives). Treat an estimate as a starting point, never a verdict.

measured target Anchored at the 200 Hz–1 kHz mean, the same anchor the product pages use.

Which peaks are real - and which are not

A peak (a hill above the target) is usually real. A 3 dB hill at 8,000 Hz is a bright, energetic top end you will hear every day. Dips are trickier: a very narrow dip may just be an artifact of where the measuring microphone sat, and a different lab would draw it somewhere else entirely²⁵. Community rule of thumb: before a narrow dip kills a purchase, check the same model on a second graph database⁶⁷.

What a graph cannot tell you

• How far away the music sounds. One microphone in one spot cannot capture the sense of space¹.
• Distortion at loud volumes, build quality, or how much the sample in the lab matches the one in the post⁸.
• Your ears. Your ear canals are a different shape from the rig's, so your own hearing of the same unit differs too. The graph is a map, not the territory.

A five-second reading routine

1. Is the chart adjusted for the ear? Find the target line first.
2. Bass (about 20-250 Hz): how far above the line? More lift reads as warmer - heavier, with more body; far too much and voices turn muddy, blurred as if underwater.
3. Mids (about 250-2,000 Hz): near the line means vocals and guitars sit forward; a scoop here reads as distant.
4. Treble (about 6-10,000 Hz): a narrow 10 dB spike promises harsh "s" sounds; a gentle rise promises air - an open, breathy quality in the highest notes.
5. Then check the label: measured or estimated?

Want to practise on real curves? Every measured product here has a live graph page - two contrasting tunings to start: the Truthear HEXA (near-neutral - close to an even, level line) and the SIMGOT EW200 (V-shaped - bass and treble lifted, vocals a step back). And once you can read the graph, you can correct toward any target yourself - the presets ship free.