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Piano note

A1 55.00 Hz

A1 is piano key 13 of 88, MIDI 33, at 55.00 Hz. It sits in the deep left-hand register, felt as much as heard.

  • Key 13 of 88
  • MIDI 33
  • -36 semitones from A4

A1

Frequency, piano key and harmonics

A1 is piano key 13 of 88, MIDI 33, at 55.00 Hz. It sits in the deep left-hand register, felt as much as heard.

Frequency55.00 HzA4 = 440
MIDI33
Piano key13 of 88
From A4-36 st
Period18.182 ms
Wavelength6.24 m343 m/s
HarmonicFrequencyNearest equal-tempered note
1 · fundamental55.00 HzA1 (+0 ¢)
2×110.00 HzA2 (+0 ¢)
3×165.00 HzE3 (+2 ¢)
4×220.00 HzA3 (+0 ¢)
5×275.00 HzC♯4 (−14 ¢)
6×330.00 HzE4 (+2 ¢)

Piano playback uses the nearest piano sample, played faster or slower, plus a sine wave at the exact pitch. The sine button is the exact equal-tempered frequency. Neighbors: G♯1 and A♯1. Arbitrary pitches and alternate A4 tunings belong on the calculator.

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Hear the note. Then name the interval.

Interval and chord drills in the app are built on this same piano and this same tuning.

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  • EQ & compressionDaily drills on drums, bass, guitars and full mixes.
  • Intervals & chordsPiano training that uses the same note names as these pages.
  • Studio toolsMetronome, tone generator and tap tempo live in the app too.

Explore the cluster

G♯1 One semitone down. Lower neighbor → A♯1 One semitone up. Upper neighbor → Note calculator Retune A4 or type any frequency. Open calculator →

FAQ

A1 questions

What frequency is A1?

55.00 Hz when A4 is 440 Hz. Change the reference on the note calculator if you need another tuning. This page does not change.

What MIDI note is A1?

MIDI 33. Piano key 13, counting A0 as key 1 and C8 as key 88.

How loud should I listen?

Keep the tone at a conversation level. These pages can generate steady tones and noise, which fatigue your ears faster than music. If anything rings or feels uncomfortable, stop and turn the volume down.