The Beatles · Let It Be
One After 909
One After 909 is in B major at 184.6 beats per minute.
Tempo
185 BPM · Prestomedian of 271 analyses · 91.2–184.6 across the middle eight tenths- Key
- B major5 sharps · the key most of the analyses agreed on
- Agreement
- 97%share of analyses that agreed
- Analyses
- 271people who ran the extractor
- One beat
- 325milliseconds, 60,000 ÷ BPM
- Tuning
- 450.5Hz · +41 cents from A 440
- Dynamics
- 3.19dB the level wanders from its average
- Loudness
- 0.913Essentia's 0–1 scale, not dB
- Danceability
- 1.13Essentia's danceability, 0–3
Source: AcousticBrainz, dump of 2022-06-23 (CC0) · MusicBrainz core data, 2026-09-17 (CC0) · how each number is measured. Measured up to 23.06.2022 — AcousticBrainz stopped collecting in 2022, so nothing released after that date is here.
What the numbers say
271 independent analyses of this recording were submitted to AcousticBrainz. All but a handful of them — 97% — put it in B major, a key signature of 5 sharps. The tempo printed above is the median of the 271 readings; 76% of them land within 2% of it, and the middle eight tenths of them run from 91.2 to 184.6 BPM.
At 184.6 BPM one beat lasts 325 milliseconds, so a sixteenth note is 81.3 ms and a dotted eighth 243.8 ms — the delay times for this recording. Counted half as fast it is 92.3 BPM, counted twice as fast 369.2. A score would mark that Presto, by the ranges this site uses.
The analyses put the reference pitch of the recording at 450.5 Hz, which is 41 cents above concert A at 440 Hz — far enough that playing along at 440 Hz will sound wrong. That is a fact about this transfer of the music, not about how it was played.
The dynamic complexity of the recording measures 3.19 dB: that is how far the level wanders from its own average, so a small number means a loud, flat master and a large one means a recording that still breathes. Its average loudness is 0.913 on Essentia's 0-to-1 scale, which is not decibels and is not comparable to a streaming service's number.
10 other recordings here are in B major; the ones listed below are the closest in tempo.
Beats per bar are not in this dataset. AcousticBrainz's analysis reports a tempo, a key and a loudness, and no time signature at all, so this page does not print one — a 4/4 here would be a guess dressed as a measurement.
Keys that fit with B major
Each of these differs from B major by at most one accidental, or shares its tonic. That is the whole of what a mixing wheel encodes; here the relations are named instead of numbered.
Delay times at 185 BPM
| Note value | Beats | Milliseconds | Hertz |
|---|---|---|---|
| Whole note | 4 | 1300.1 | 0.77 |
| Half note | 2 | 650.1 | 1.54 |
| Dotted quarter | 1.5 | 487.5 | 2.05 |
| Quarter note (one beat) | 1 | 325 | 3.08 |
| Quarter triplet | 0.667 | 216.7 | 4.61 |
| Dotted eighth | 0.75 | 243.8 | 4.1 |
| Eighth note | 0.5 | 162.5 | 6.15 |
| Eighth triplet | 0.333 | 108.3 | 9.23 |
| Dotted sixteenth | 0.375 | 121.9 | 8.2 |
| Sixteenth note | 0.25 | 81.3 | 12.31 |
| Sixteenth triplet | 0.167 | 54.2 | 18.46 |
| Thirty-second note | 0.125 | 40.6 | 24.61 |
Half time 92.3 BPM · double time 369.2 BPM. Every row is one beat (325 ms) times the fraction in the second column.
Closest in key and tempo
- Downblink‐182B major185BPM
- River Runs, New Grown PlumsNeil DiamondB major172BPM
- When We DanceStingB major167BPM
- In One EarCage the ElephantB major165BPM
- UptightGreen DayB major164BPM
- For Your Eyes OnlySheena EastonB major164BPM
- I’m a BelieverSmash MouthB major164BPM
- For No OneThe BeatlesB major164BPM
- I Wanna Be SedatedRamonesB major163BPM
- Kentucky WomanNeil DiamondB major163BPM
Recordings in B major, ordered by how near their tempo is to 185 BPM. A calculation, not a recommendation.
All songs in B majorAll songs at 185 BPMThe Beatles
MusicBrainz collapses 105 recording ids into this one. Recording id e1f05d06-06ad-4f22-9c81-c94c0f44fe41.