I am finding confusing information concerning guitar string 6's frequency. Many articles claim it to be E2. How can it be E2 when string 6 is E below middle C which is E3?

  • Given, that there are several octave numbering schemes, this is hard to answer. But the interval between strings is constant, so which octave has your fifth string?
    – guidot
    Apr 5, 2023 at 14:52
  • 4
    See also: Why is guitar music written one octave higher?.
    – Aaron
    Apr 5, 2023 at 16:05
  • @guidot I think it’s clear from context that the asker considers middle C to be C4. Apr 5, 2023 at 17:10
  • I am going by the common expression that middle C is C4 261.6 Hz.
    – ejbpesca
    Apr 6, 2023 at 10:52
  • 1
    @ejbpesca No, that's the small c, or C3, an octave lower. If you want to play a middle C, go to the B string, fret 1.
    – Divizna
    Apr 6, 2023 at 11:23

4 Answers 4


Empty guitar strings are:

  • great E, aka E2, ~82.4 Hz
  • great A, aka A2, 110 Hz
  • small d, aka D3, ~147 Hz
  • small g, aka G3, ~196 Hz
  • small b, aka B3, ~247 Hz
  • one-lined e', aka E4, ~330 Hz

Neither the high E nor the low E string is the small e (E3).
The high E (string 1) is the one-lined e' (E4), a major third above middle C and a fourth below chamber A.
The low E (string 6) is the great E (E2).

  • This answer addresses the question without any extraneous information. Thank you.
    – Wastrel
    Apr 6, 2023 at 14:12
  • 1
    Great E? Small D? One-lined E? This is a notation I've never heard of before; I'd be interested in learning more about it. Is it a guitar-specific thing, or a regional thing, or what?
    – Hearth
    Apr 6, 2023 at 14:49
  • @Hearth Regional, it seems. I'm afraid the numbered notation feels rather foreign to me in turn - that is something I've seen at the English-speaking internet and nowhere else. Wikipedia has an article, and a handy table in the Octave article.
    – Divizna
    Apr 6, 2023 at 15:42
  • @Divizna I had no idea Helmholtz did research into acoustic physics; I know of him for a few contributions to my field, electrical engineering. You say english-speaking; what language does your notation usually get used in? I'd guess German, as Helmholtz was German?
    – Hearth
    Apr 6, 2023 at 18:35
  • @Hearth I don't know. It's definitely the unambiguous standard in my country, and unsurprisingly, it seems to be the standard for German-speaking places, too. Other than that, beats me. If I were to guess, I'd place my bet on "the entire northern half of Europe from British Isles to Russia", but it's really just a largely uninformed guess and I may be completely wrong.
    – Divizna
    Apr 8, 2023 at 14:38

The guitar is a quasi-transposing instrument because it sounds an octave lower than written. When we read E3 on a score and then play the lowest string on the guitar, the sound that comes out is E2. When we read middle C on the score and play the third fret of the A string the sound that comes out is C3.

For transposing instruments, each fingering has two pitches related to it. There’s the “written” pitch, which means when we see that note in sheet music, we play that fingering. The other pitch related to a specific fingering is the “concert” pitch, which is the pitch (similar to frequency) that we hear coming from the instrument as the actual sound.

On the guitar, every fingering has a concert pitch that is an octave lower than the written pitch. So when we see middle C written on the page, we play the fifth string, third fret. And when we play that, what we hear is an octave below middle C.

Since every string and fret combination on guitar has two pitches associated with it, we have to give two answers to the question “is string five, fret 3 middle C?” It is and it isn’t. It is middle C written, but it’s an octave below middle C concert.

  • 3
    To be more concrete the guitar is what we consider a tenor instrument, which are notated in treble clef but sound an octave lower.
    – Lazy
    Apr 5, 2023 at 13:50
  • 4
    Why the phrase “quasi-transposing”? “Octave transposing” is a standard phrase and description for instruments like guitar, flute and piccolo to name a few. Apr 5, 2023 at 16:22
  • 5
    @JohnBelzaguy There’s no way to talk about guitar transposition without getting criticism for the terminology used, so I made up my own term - not to avoid criticism, but to own the criticism. Apr 5, 2023 at 17:09
  • 3
    It's a 'transposing instrument'. More specifically, an 'octave transposing instrument'. Nothing quasi about it.
    – Laurence
    Apr 5, 2023 at 20:55
  • 4
    In a sane world, guitar would be notated with an explicit octave-shifted treble clef — with a small subscript ‘8’ to indicate that the notes sound an octave lower than written — and there would be no ambiguity (nor any need to pretend that it's a transposing instrument)…
    – gidds
    Apr 6, 2023 at 15:37

Guitar is written in treble clef, but sounds an octave lower than written. Sometimes we use the 'treble (down 8)' clef which makes this transposition explicit.

There are (at least) two numbering conventions for pitch. One of them calls Middle C 'C4'. Another calls it 'C3'. But whatever you call it, guitar sounds one octave lower. enter image description here

  • Is there a functional purpose to not placing guitar notes to the staff at the correct position of their sound?
    – ejbpesca
    Apr 6, 2023 at 11:00
  • 2
    @ejbpesca Yes, you want them in the staff where they can be easily read, not a messy bunch of ledger lines below.
    – Divizna
    Apr 6, 2023 at 11:38
  • 1
    @Divizna That makes sense as to why you wouldn't write them as-heard on a treble clef. But for me, it just shifts the question - why not place the notes in the correct position on a bass clef? No extra ledger lines required. Apr 6, 2023 at 13:18
  • 1
    @NuclearHoagie I guess because way fewer people are literate in the bass clef than treble. (And when a guitarist makes the effort to learn a second system, they're likely to go with tabs.)
    – Divizna
    Apr 6, 2023 at 13:42
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    @NuclearHoagie treble clef is actually optimal in terms of the number of ledger lines needed to notate lots of guitar music, see music.stackexchange.com/q/101432/63781 and music.stackexchange.com/q/118892/63781 Apr 6, 2023 at 18:34

In standard tuning guitar string 6 produces E2.

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