Hearspan

What Hearspan trains

Hearspan trains interval reproduction: hearing the distance between two pitches and rebuilding that same distance starting from a completely different tone. That is transposition by ear. The interval is what stays constant when a song is moved into a comfortable key, and carrying one to a new starting point is a different skill from recognising or naming it. Nothing here asks for a name, only for the same gap somewhere else.

How to play

Each round begins with a reference interval: two tones, A then B, played one after the other. Press Play reference as often as you need. Then you get a new starting tone, C, and a slider that sets a second tone, D. Move the slider, press Play C then D to hear your attempt, and keep adjusting until the gap C to D sounds like the gap A to B. When it does, press Lock in D.

The slider runs 700 cents below the starting tone to 700 above, in single-cent steps, showing the signed value you set. It starts each round at zero, which is unison, so every round begins from no interval at all. Direction matters: the reference may go up or down, and across the four rounds you get two of each in a shuffled order. The reference also narrows as you go, from about 350 cents in round one to roughly 160 in round four, and the margin you are allowed narrows with it.

How scoring works

Each round scores your error against that round's tolerance: land exactly on the reference and you score 100, land a full tolerance away and you score 0, with everything in between scaled in a straight line. The four rounds are averaged into your span accuracy out of 100. A round at 85 or above counts as spot-on and advances straight away; below that, the slider snaps to the correct interval and the reference is replayed before you continue. A final accuracy of 60 or more earns the day toward your streak.

What your score means

Read the accuracy as a rough band, not a verdict:

One session is noisy. The trend across many days is the honest signal.

Common mistakes

The most common error is matching the destination instead of the distance: you remember roughly how high B sounded and slide D toward that pitch, even though C started somewhere else entirely. The reference is a gap, not a note. Second, ignoring the direction: a downward reference reproduced upward is the right size and the wrong answer. Third, locking in after one comparison; playing C-then-D two or three times against a fresh reference costs nothing. Fourth, trusting the number on the slider instead of your ear: it tells you what you set, not what the reference was. Fifth, rushing the later rounds, which are narrower and less forgiving.

Practice progression

(5 min, beginner) play the daily four rounds, always hearing the reference immediately before your attempt rather than several adjustments earlier. (10 min, intermediate) use the practice tab, where the interval width runs from 120 to 600 cents and the round count from two to eight; intervals under 200 cents are a different task from wide ones. (weekly) pair it with Hearecho, which removes the reference entirely, and read the interval ear-training guide so the sizes you reproduce start acquiring names.

The science behind it

An interval is a ratio of frequencies, not a difference in hertz, which is why the same interval sounds the same wherever you start it and why it is measured in cents. Human hearing is far better at relative pitch than absolute pitch: most people cannot name a tone heard in isolation, yet can tell that two pairs of tones span the same distance. Reproducing an interval adds two demands on top of hearing it. You hold the reference in auditory working memory while you work, and you search for a match by producing candidates and comparing, which is the loop a singer runs when finding a note. The memory part fades within seconds, which is why replaying the reference late in your search helps more than replaying it early. See musical intervals explained and cents.

Limitations

Hearspan is a game and an informal self-check, not a clinical or diagnostic tool. It measures reproduction with a slider, which is not the same as singing or playing an interval, where the instrument or the voice adds its own difficulty. Browser audio and headphones vary between devices, so results are not strictly comparable, and four rounds reflect concentration on the day as much as ability.

Where it shows up

Carrying an interval to a new starting point is one of the most practical things an ear can do. A singer handed a song that sits too high transposes it down and has to keep every leap in the melody the same size from a new key; get one interval wrong and the tune is no longer the tune. A guitarist playing along with a recording finds the first note by ear, then follows the shape of the line rather than the absolute pitches. A capo forces the same move: the instrument shifts, the intervals do not. A backing singer improvising a harmony holds a fixed distance above the melody and moves with it note for note. Outside performance, a teacher demonstrating a phrase an octave lower is transposing on the fly, and listeners recognise the tune anyway, because a melody is stored as a pattern of distances rather than a list of pitches. That is why a song sung by a child and by an adult is the same song without a single shared frequency. Hearspan strips that down to one gap at a time.

Related reading & games

• Musical intervals explained: what stays constant when you transpose.
• The interval ear-training guide and the octave.
• Heartween and Hearecho: the midpoint and the memory versions.
• All ear-training guides.