Method · measured
How we measure recordings.
Tabs give the tuning. The record gives the pitch. This is how TuneLit reads that pitch from a song, and how far to trust it.
The idea
From a record to a number
Every note in a song sits on a grid of twelve notes per octave. On a record tuned to A 440, the notes land on the grid lines. On a record tuned 21 cents flat, every note lands 21 cents below them. TuneLit measures that shift, in cents, and turns it into a reference A you can set on the tuner.
- Find the strongest notes. We take 90 seconds of each song, from 0:45, and pick out the strongest steady tones: the notes and the overtones that sit on the grid.
- Compare them with the A 440 grid. Each tone lies some number of cents from the nearest grid line. Drum hits, slides, vibrato and mains hum get little or no weight.
- Average on a circle. 100 cents above one note is the next note, so the distances wrap around like a clock face. A circular average handles the wrap, and one clear direction means the notes agree.
- Check the agreement. When the notes agree, confidence is high. Noise, speech, hum alone or music outside the 12-note grid stays low.
- Combine the songs. The album value is the middle of its songs, weighted by confidence. A song gets its own value only when it differs from the album by 8 cents or more, measured with good confidence and not contradicted by a second copy (CD or LP), or by 6 cents or more when the CD and the LP show the same difference.
The result is known within one semitone. The grid repeats every 100 cents, so E Standard 60 cents flat and E♭ Standard 40 cents sharp look the same. Which semitone the guitars sit on comes from interviews, the press and tabs; the measurement adds the cents. When the semitone is in doubt →
Accuracy
How close does it get?
- < 1 ¢worst error on 90 test songs: offsets from −45 to +49 ¢, clean, with noise, vibrato, drums or a phone-mic filter
- ≤ 4 ¢hard cases: distorted palm-muted chugs, vinyl and cassette wow, chorus, mains hum under the music
- 5.9 ¢median error on 21 real songs pitch-shifted to E Standard by hand; 17 of 21 within 10 ¢
The test songs are built in code with a known offset, so every error is exact. TuneLit's test suite fails if any of them is off by more than 2 ¢ clean or 4 ¢ in the other conditions, so these figures are checked on every change.
Real records are harder. The 21 hand-shifted songs include the error of the shifting itself. The worst one read 18.6 ¢ off, and the analysis flagged it as unreliable (confidence 0.09); among the songs it trusted, the worst was 12.4 ¢.
Limits
What can throw it off
- Turntable speed. A needle drop from a turntable running 0.3 % fast or slow moves by about 5 cents, so LP values can sit a few cents from the CD.
- Heavy distortion. Dense, distorted mixes give fewer clean tones. Confidence drops, as on St. Anger or Far Beyond Driven, and single songs scatter more.
- Live recordings. Bands retune between songs and drift on stage. We have not measured live albums; start from the studio value and trust your ears.
- Tape or tuning? A measurement hears the result, not the cause. It cannot tell a guitar tuned low from a tape that ran slow.
- Effects. Pitch-shift pedals move notes on purpose. Short passages barely count, but a song built on one can read oddly.
- Rounding. Values within ±4 ¢ count as concert pitch: nobody hears that against a band.
The semitone
Between two notes
The measurement knows the cents, not the semitone. Usually that is enough: a record 16 cents sharp of E is plainly E Standard. It gets hard when a record sits near the middle between two notes, 35 to 65 cents from the note the tabs name. A tuner set to A 440 can show either note, Dimebag Darrell named the note above, and tabs of one song can disagree by a half step.
The Great Southern Trendkill shows how that goes wrong. Tabs and the press call it C♯ Standard, and sources say Pantera tuned about 60 cents flat, so we first listed the album as C♯ 50 cents flat and Floods as C♯ 64 cents flat. The strings sit a half step higher: D, about 50 and 64 cents flat. An A 440 tuner reads that as C♯ +50 and C♯ +36, which is where the tabs' C♯ comes from. Both are fixed.
- Between two notes: 15 songs. Each is listed in the semitone the tabs, the sources and the audio check point to. If one sounds a half step off against the record, shift the tuner by a half step. Tunings the band itself named keep their semitone.
- Checked from the audio: 2 songs. A second check listens for the lowest open string: the bass and the guitars play it often, and the note just under it almost never. On songs it was not trained on, it is right 98 % of the time when it answers, and not sure 7 % of the time. When it disagreed with the tabs, though, it was right only 1 time in 4: a song that never plays its open low string fools it. So it moves a song only when a tab or a source points the same way: Drag the Waters in C♯ Standard and Hellbound in D Standard.
What we found
Metallica: what sources said, what we measured
Album values from the primary source, with the other copy in brackets, and the songs that differ by 8 cents or more. Every Metallica album and song →
| Album | Sources said | TuneLit measured | Equivalent A |
|---|---|---|---|
| Kill 'Em All (1983) | about +20 ¢ | +15.6 ¢ (CD; LP +16.9 ¢) | A ≈ 444.0 |
| Ride the Lightning (1984) | about +20 ¢ | +7.9 ¢ (CD; LP +2.8 ¢) | A ≈ 442.0 |
| · For Whom the Bell Tolls | about +50 ¢ | +45.5 ¢ | A ≈ 451.7 |
| · Fade to Black | about +20 ¢ | +21.7 ¢ | A ≈ 445.5 |
| · Creeping Death | about +20 ¢ | +22.4 ¢ | A ≈ 445.7 |
| Master of Puppets (1986) | A 440 | +2.1 ¢ (CD; LP +3.7 ¢) | A ≈ 440.5 |
| · Master of Puppets | A 440 | −16.8 ¢ | A ≈ 435.8 |
| The $5.98 E.P. (1987) | A 440 | +4.8 ¢ (CD; LP +2.6 ¢) | A ≈ 441.2 |
| · The Small Hours | A 440 | +21.6 ¢ | A ≈ 445.5 |
| ...And Justice for All (1988) | A 440 | +3.9 ¢ (LP) | A ≈ 441.0 |
| · One | about +20 ¢ | +19.3 ¢ | A ≈ 444.9 |
| The Black Album (1991) | A 440 | +5.2 ¢ (CD; LP +6.2 ¢) | A ≈ 441.3 |
| Load (1996) | A 440 | −1.3 ¢ (CD; LP +2.0 ¢) | A ≈ 439.7 |
| ReLoad (1997) | A 440 | +4.7 ¢ (CD; LP +5.0 ¢) | A ≈ 441.2 |
| · Devil's Dance | A 440 | −8.3 ¢ | A ≈ 437.9 |
| Garage Inc. (1998) | A 440 | −1.7 ¢ (CD; LP −5.7 ¢) | A ≈ 439.6 |
| · Whiskey in the Jar | A 440 | +10.8 ¢ | A ≈ 442.8 |
| · Helpless | A 440 | +6.5 ¢ | A ≈ 441.7 |
| · The Small Hours | A 440 | +21.6 ¢ | A ≈ 445.5 |
| · Killing Time | A 440 | +7.6 ¢ | A ≈ 441.9 |
| St. Anger (2003) | A 440 | −3.4 ¢ (CD; LP −9.6 ¢) | A ≈ 439.1 |
| · Some Kind of Monster | A 440 | −14.1 ¢ | A ≈ 436.4 |
| · Dirty Window | A 440 | +10.6 ¢ | A ≈ 442.7 |
| Death Magnetic (2008) | A 440 | −1.0 ¢ (CD; LP −3.8 ¢) | A ≈ 439.7 |
| Hardwired... to Self-Destruct (2016) | A 440 | +2.1 ¢ (CD; LP +2.7 ¢) | A ≈ 440.5 |
What we found
Pantera: what sources said, what we measured
Album values from the primary source, with the other copy in brackets, and the songs that differ by 8 cents or more. Every Pantera album and song →
| Album | Sources said | TuneLit measured | Equivalent A |
|---|---|---|---|
| Metal Magic (1983) | no pitch given | +14.6 ¢ (LP) | A ≈ 443.7 |
| Projects in the Jungle (1984) | no pitch given | −34.8 ¢ (LP) | A ≈ 431.2 |
| I Am the Night (1985) | no pitch given | −36.5 ¢ (LP) | A ≈ 430.8 |
| · Onward We Rock! | no pitch given | −45.6 ¢ | A ≈ 428.6 |
| Power Metal (1988) | no pitch given | −30.3 ¢ (CD; LP −30.7 ¢) | A ≈ 432.4 |
| · Power Metal | no pitch given | −1.3 ¢ | A ≈ 439.7 |
| · Over and Out | no pitch given | −21.6 ¢ | A ≈ 434.5 |
| · Down Below | no pitch given | −39.0 ¢ | A ≈ 430.2 |
| · P*S*T*88 | no pitch given | −21.8 ¢ | A ≈ 434.5 |
| Cowboys from Hell (1990) | A 425 (−60 ¢) | −20.6 ¢ (CD) | A ≈ 434.8 |
| · Cemetery Gates | A 425 (−60 ¢) | −32.1 ¢ | A ≈ 431.9 |
| Vulgar Display of Power (1992) | A 425 (−60 ¢) | −57.4 ¢ (CD) | A ≈ 425.7 |
| · This Love | A 425 (−60 ¢) | −72.8 ¢ | A ≈ 421.9 |
| · Hollow | A 425 (−60 ¢) | −70.4 ¢ | A ≈ 422.5 |
| Far Beyond Driven (1994) | A 425 (−60 ¢) | −44.1 ¢ (CD) | A ≈ 428.9 |
| · Hard Lines, Sunken Cheeks | A 425 (−60 ¢) | −60.3 ¢ | A ≈ 424.9 |
| · Shedding Skin | A 425 (−60 ¢) | −65.9 ¢ | A ≈ 423.6 |
| · Planet Caravan | A 425 (−60 ¢) | −63.1 ¢ | A ≈ 424.3 |
| The Great Southern Trendkill (1996) | A 425 (−60 ¢) | −49.5 ¢ (CD) | A ≈ 427.6 |
| · Floods | A 425 (−60 ¢) | −64.3 ¢ | A ≈ 424.0 |
| Reinventing the Steel (2000) | A 425 (−60 ¢) | −37.7 ¢ (CD) | A ≈ 430.5 |
| · Yesterday Don't Mean Shit | A 425 (−60 ¢) | −46.4 ¢ | A ≈ 428.4 |
| · Uplift | A 425 (−60 ¢) | −23.9 ¢ | A ≈ 434.0 |
Privacy
The audio stays with us, the numbers go on the page
We measured CD editions and needle drops of original LPs from our own library: 21 albums by Metallica and Pantera so far. The audio is never uploaded, stored on the site or published; only the numbers appear on TuneLit. For how the live tuner reads a single string, and how accurate that is, see how the tuner listens.
Questions
Can a measurement tell E Standard from E♭ Standard?
No. The grid repeats every semitone, so E Standard 60 cents flat looks exactly like E♭ Standard 40 cents sharp. The semitone comes from interviews, the press and tabs; the measurement adds the cents.
Why do the CD and the LP give different values?
Mostly turntable speed: 0.3 % fast or slow moves a needle drop by about 5 cents. Different masters can differ too. The album pages show both, and the Tune buttons use the primary source.
Is A 425 the same as 60 cents flat?
Yes, near enough. A at 425 Hz is 60 cents below 440 Hz. Setting the reference to 425 and tuning to E Standard gives the same strings as tuning every string 60 cents flat at A 440.