Two separate abilities
Absolute pitch is the ability to hear a note with nothing to compare it against and name its pitch. Relative pitch is the ability to hear two notes and judge the distance between them. The first is closer to reading a label attached to a sound; the second is closer to measuring. The distinction matters, because possessing absolute pitch does not guarantee accurate judgement of intervals, and plenty of people judge intervals precisely without it. Folding both under the single phrase "a good ear" makes it impossible to tell which one is under discussion, and that omission is behind much of the confusion in conversations about musical ability.
They are not equally easy to acquire
Absolute pitch has repeatedly been linked to musical exposure in early childhood, and acquiring it in adulthood is reported to be difficult. Training can improve an adult's ability to identify notes to some degree, though the immediacy shown by those who have had it since childhood appears hard to reach. Other contributing factors have been examined, including whether a speaker's language is tonal and whether genetic predisposition plays a part, but how much each contributes remains unsettled. Relative pitch sits in a different position: judging the distance between two notes is reported to improve with training well into adulthood, and that asymmetry has practical consequences.
Musical practice runs on relative pitch
Playing in an ensemble means continually matching your pitch to the other players. Working out a melody by ear goes faster by tracing intervals than by routing every note through its name. Transposing an accompaniment into a different key is manageable once chords are understood as combinations of intervals. All of this is relative pitch at work. That music theory is built on relative descriptions — scale degrees, chord symbols, figured bass — reflects the same fact: intervals, not absolute pitches, are the working currency. Absolute pitch can be a useful auxiliary, but it is not the foundation that music rests on.
When absolute pitch gets in the way
Absolute pitch is not a uniform advantage. Playing from transposed notation puts the written note name and the sounding pitch out of alignment, and having names arrive automatically is reported to interfere rather than help. Players of transposing instruments describe this friction, as do performers working with the different reference pitches used in early music. In an ensemble that has settled slightly flat, insisting on the pitch you remember can pull you away from everyone else. Absolute pitch attaches names to sounds; whether those names suit the situation is a separate question. Understanding this keeps the ability from being overvalued.
The myth that you need it
The idea that absolute pitch certifies musical talent is remarkably persistent. Performance, though, draws on a wide range of capacities: an ear for intervals, a steady sense of pulse, fine motor control, an understanding of how a piece is put together, and the attention needed to breathe with other players. Absolute pitch is not even one of those pillars — it is closer to a convenience that some people happen to have. Among people who have spent years in music, the reported proportion with absolute pitch is lower than popular belief suggests. Using it as a test of talent misreads what musicianship consists of.
Focus on what responds to practice
That relative pitch answers to training is the encouraging part. Repeatedly comparing two notes changes where your attention goes, and judgements grow finer. Reading that improvement as a gain in the underlying ability calls for caution, since whether the benefits of cognitive training extend beyond the trained task has been debated for a long time. A rising score is best taken, first of all, as evidence of familiarity with the task. The pitch perception test on Bench measures exactly this relative judgement: it narrows the gap between two notes step by step and records the smallest difference you could still hear. Used as a way to watch your own record move rather than to rank yourself against others, it earns its place.