What is soundstage in headphones and speakers?

Width, depth and height

Soundstage describes the space as a whole: how wide the music spreads from left to right, how deep it runs from front to back, and sometimes how tall it seems. Where each instrument sits inside that space is a separate quality, imaging, and the two vary independently.

Width starts in the mix, which places each source somewhere between the two channels. On speakers those positions spread along the line between the cabinets, so the angle the speakers make at your seat sets the basic width. The standard layout, the listening triangle, puts you at one corner of an equilateral triangle with the speakers 60 degrees apart. Wide recordings and reflections from the side walls can make the space seem to reach past the speakers.

Depth comes from distance cues in the recording. A distant source is quieter than a close one and reaches the microphones with more reverberation relative to its direct sound, and your ear reads both as distance. The Kiwi Ears Orchestra Lite shows that depth and width are separate: its review finds the width limited, closed-in even by in-ear standards, while the depth is well defined, so you can hear a source move closer or further back.

Height is the least dependable of the three. Two-channel stereo has no channel for it, and where a sound seems to sit vertically varies from one listener to another.

Where the space comes from

The recording decides most of it. An orchestra recorded with a pair of microphones in a concert hall arrives with the hall's reverberation and the players' layout. A studio track built from close-miked parts, each placed with a pan control, carries little space beyond what the engineer added with artificial reverb. A system presents that space, and some add a little of their own.

The Kiwi Ears Atheia is one that adds. It exaggerates the reverb in recordings, which its review hears as a larger-than-life, atmospheric presentation that can turn messy when a track gets busy. It also stages instruments and vocals a step farther away than usual, which adds to the sense of space and takes some intimacy away.

Tuning plays a part too. A dip in the upper midrange makes sources sound further away, which can read as a bigger stage. The HIFIMAN RE2000 PRO Silver has a recess around 2 or 3 kHz that its review hears as a little thin, and credits with a wider perceived soundstage.

Why headphones sound in your head

A real sound reaches each of your ears slightly differently. The ear nearer the source hears it a fraction of a millisecond sooner and a little louder, and your outer ears filter it in a way that changes with the direction it comes from. Your brain reads those cues as a position outside you, at a distance.

Headphones play each channel from right beside one ear. The timing and level differences between the channels survive, but the filtering matches no real direction, so the brain usually places the sound inside the head, on a line between the ears. Filter the signal through the listener's head-related transfer function, a model of how the head and outer ears shape sound from each direction, and it is heard outside instead.

In a 1991 study, Kawaura and colleagues simulated those transfer functions over headphones, and most sounds were placed outside the listener's head in the intended direction. They seemed closer than intended, and front and back were often confused near the center line. Adding the timing changes a head movement would cause cut that confusion sharply.

Binaural recordings, made with microphones in a dummy head's ears, and spatial-audio processing both work on this principle. Results vary between listeners, because the dummy's ears, or the model's, aren't yours. Crossfeed is a gentler step: it feeds a little of each channel into the other, as the far speaker would, which makes hard-panned mixes less extreme without adding the outer-ear cues that place a sound outside you.

Headphones still differ in how far out they get. The OneOdio Max 1 is a closed-back wireless model, and its review found that the music doesn't feel completely trapped inside the head, though the reviewer couldn't tell whether DSP was involved. The front-to-back position of the stage varies too. The HIFIMAN Edition XS review hears a very wide stage with everything a little further away than expected, vocals that seem to come from the back of the head and highs from slightly above.

Judging a stage from a review

A soundstage claim only means something against a comparison. "Wide" needs a reference headphone, a recording and a chain, and the useful reviews name all three. Check which dimension is meant too. A headphone can be wide and shallow or narrow with plenty of depth, and "intimate" usually means a small stage with sources close to you.

Level matters as well. Compare two headphones at the same loudness, since the louder one tends to win any comparison, which is why the comparisons in our reviews are level-matched.

You can check a stage at home with two recordings you know: a close-miked studio track and a live recording made in a hall. The hall should sound clearly bigger, with players set back behind one another. The difference between the two tells you more about a headphone's stage than either track does alone.

Buying for a bigger stage

Start with what you play. Large-scale classical and live recordings carry far more space than close-miked pop, so a big stage matters most to people who listen to them. Open-backs are generally heard as more spacious than closed-backs and suit a quiet room, and the best open-back headphones guide ranks the ones reviewed here.

In-ears usually present the smallest stage, and the reviews here often call them closed in, though a few reach wider than their size suggests. If you care more about where each instrument sits than about the size of the space, that is imaging, and its explainer covers what sharpens or blurs it.