Why can music sound out of tune after sudden hearing loss?

First: if it's happening now, go today

Sudden sensorineural hearing loss (SSNHL, or "sudden deafness") is hearing that drops over hours or up to three days, usually in one ear. It's a medical emergency:

• See a doctor immediately, at urgent care or an ENT. Say "sudden hearing loss in one ear".
• Treatment works best early. US guidelines say doctors may offer steroids within two weeks of the loss starting. Treatment delayed by more than two to four weeks is less likely to help.
• Don't assume it's wax or a cold without a doctor looking. The two can feel similar at first.

About half of people with sudden hearing loss recover some or all of their hearing on their own, usually within one to two weeks. It affects roughly 1 to 6 people in every 5,000 each year, and probably more, since many cases go undiagnosed.

Why pitch changes along with hearing

Your inner ear sorts sounds by pitch along its length, and your brain reads pitch partly from where a sound makes it vibrate. An injury to the inner ear in one ear can shift that map, so the same note lands in a slightly different place and sounds like a different pitch in that ear. That is binaural diplacusis.

Because sudden hearing loss usually hits one ear, the two ears end up disagreeing. People notice it most with music: a familiar song sounds detuned, a singer seems flat, chords clash. Researchers have measured this directly: in one documented case of sudden hearing loss in one ear, the two ears heard the same tones up to 12% apart in pitch at high frequencies. That's about two semitones.

Does the pitch come back?

In that same case, the patient was treated with steroids. Their hearing thresholds recovered fully by four weeks, and the diplacusis went back to normal a little later. That's a single case, not a study, but it shows pitch can recover along with hearing.

When hearing doesn't recover fully, the mismatch can remain. There's no research yet on how it changes over months or years after sudden hearing loss, though adult pitch perception can adapt. Read what's known about whether diplacusis goes away.

After the urgent phase

Once a doctor has assessed and treated the loss:

• Keep your follow-up hearing tests. They show how much hearing has come back.
• Tell your audiologist about the pitch. A standard hearing test measures how quiet a sound you can hear, not what pitch you hear, so it won't show diplacusis unless you mention it.
• Track it yourself. Measuring your pitch mismatch the same way every week or two shows whether it's improving, holding or getting worse, which is useful to share with your audiologist.

That's what Harmonic Recovery was built for. It measures the gap between your ears in cents at six frequencies, with a setup that keeps measurements comparable over time. It also lets you practice with your own music, with a pitch hint in your better ear. It doesn't treat sudden hearing loss or replace your doctor's care. See how it works.