Diplacusis for musicians and singers

Why musicians notice it first

Most people would shrug off a small pitch difference between their ears. Musicians can't: you tune to a few cents, you hear when a chord's third is sour, and you know exactly how a recording should sound. A mismatch of a quarter of a semitone, which a non-musician might never notice, can make every chord you play sound wrong.

Musicians describe it as:

• an instrument that tunes perfectly with a tuner but sounds out of tune in one ear
• chords and harmonies that beat or clash when they shouldn't
• trouble singing in tune, or your voice sounding flat or sharp on one side
• ensemble playing where everyone seems slightly off
• in-ear monitors or headphones making it much more obvious

How common is it in musicians?

Less studied than it should be. A 2018 systematic review of hearing in professional musicians found that diplacusis was examined in only two studies, covering 380 players. About 6% had it, more in the classical players studied than in the pop and rock players. The same review found hearing loss far more often. Because diplacusis usually comes with some hearing damage, anything that damages hearing, including years of loud rehearsal and performance, raises the risk.

What causes it

Diplacusis happens when the inner ear of one ear maps pitch differently from the other, usually because of damage or fluid changes in that ear. For musicians, the usual suspects are:

• noise exposure: loud stages, rehearsal rooms, monitors, and one-sided sources like a drummer's cymbal or a violin under the chin
• sudden hearing loss, which needs a doctor straight away
• Ménière's disease and other inner-ear conditions

Loudness matters too: in damaged ears, pitch can shift more than normal as sound gets louder. So the mismatch may be worse at performance volume than in quiet practice.

Measuring it like a musician

You'll want numbers, and you can get them. Pitch mismatch is measured in cents, the same unit as your tuner. The method is pitch matching: a tone in one ear, then the other, adjusted until they sound the same. A careful measurement:

• plays the ears one at a time, never together
• matches loudness first
• tests several frequencies, since the mismatch is often worst in one register
• repeats each match, so you know your own normal variation

Try the free online pitch check for a first reading. Knowing which register is worst is useful: it tells you where to trust your other ear, or a tuner, rather than the affected one.

Practical tips

• Protect your hearing: musician's earplugs with flat attenuation, sensible monitor levels, rest after loud sessions.
• Tune with a tuner or your better ear when the mismatch is large, instead of fighting what the affected ear tells you.
• Check both ears separately when something sounds off, so you know whether it's the instrument or the ear.
• Get new changes checked. A sudden change in hearing or pitch needs a doctor quickly, and an audiologist can advise on protection.

Practicing with Harmonic Recovery

Harmonic Recovery was built by someone with diplacusis, around music. It plays your own songs clearly in your affected ear while the same music fades in and out in your other ear as a pitch reference. It also offers 3-minute higher-or-lower drills in cents, and a hearing check that tracks your mismatch over time. It's a practice and measurement tool, not a treatment, and no study has tested whether the practice reduces diplacusis. The measurement will tell you honestly whether yours is changing. See how it works.