For instance I have 4 notes in the first octave: C, E, G, B. How to know if it's a Cmaj7 or an Em/C? Can we count C as a bass note?

Edit: What if it were a progression of chords all having one C note in the bass? Like: C, Em/C, Fmaj7/C, Bb/C?

  • 4
    It can't be C7, that would have Bb in it. Could be Cmaj7 or Em/C. Depends on musical context more than on spacing.
    – Laurence
    Jan 13, 2017 at 20:23
  • Can you make clear if you mean the bass note (bass part) or the root of the chord? If we are talking about the bass part, it's just the lowest note. If you want the chord root, you must make a harmonic analysis of some kind. Jan 13, 2017 at 21:27
  • @MichaelCurtis I mean the bass part of the chords. Like in my previous question about Fm and Eb/F. Jan 15, 2017 at 6:19

4 Answers 4


C E G B in that order, bottom to top, will 9 times out of 8 be called C major 7. It is a very commonly used chord, and the C underneath, being the bass note, is also the root of the chord. E gives maj3., G gives p5, while the B on top provides the major 7th part. Cmaj7.

  • What if C were an octave lower? Jan 14, 2017 at 9:11
  • Still Cmaj7 ...
    – Tim
    Jan 14, 2017 at 9:19
  • Why? It should be Em/c Jan 14, 2017 at 9:25
  • 1
    In this case, it could be either. It will depend on context. I think if you took these notes in that order, in 100 songs, 99% would call it Cmaj7 in preference.
    – Tim
    Jan 14, 2017 at 9:29
  • 1
    When ALL the notes played in a chord fit into the normal tertian pattern, and make a commonly used chord, it will be called by that name. C E G B all make a well used chord of C maj7. Calling it Em/C is done, but more usually as a passing chord, using a moving bass line, such as Em, Em/D, Em/C, B7.
    – Tim
    Jan 14, 2017 at 10:23

NOTE/EDIT before you read this, I suggest you make sure you understand the Jazz 2-5-1 progression. Most non-classical or modern songs in some part owe their origin to Jazz; understanding 2-5-1 will help understanding what the chord "really is". In fact, Jazz 2-5-1 is probably the way to "hear" most songs that were not even written as jazz or before the jazz age.

A bass note is the lowest note in a scoring, period. Regardless of what clef it's on.

The root note of a chord and the bass note may not be the same. It's that simple. Otherwise life would be very boring for the tuba players.

As to what the chord is, that's more ambiguous and you'll have to learn context (what the key of the song is, how often the chord is used). An Am7 A C E G could also be construed as a C6 C E G A. Diminished 7th chords or Augmented chords are even more problematic as they are really 4 or 3 different chords at once (they are symmetrical). Here, especially with the diminished 7ths, you have to consider context. A standard Jazz progression in C leading home from an F is:

  • F
  • F#dim 7th
  • C/G (C with a G "bass note" :)
  • A7
  • D7
  • G7
  • C (home again!)

(Play it and you'll recognize it in a lot of songs). You could call the F# dim 7th an C dim 7th if you wanted to; it would be true but most scores won't write it that way. In short, the bass note is what it is but the chord is contextual. C

  • 1
    This answer gets to the point: the OP really is asking about chord inversions and you need to determine the harmonic context before making that analysis. If we have a ii-V-I progression in C, then a chord label of Cmaj7 makes sense. Jan 16, 2017 at 15:30

First, the bass note is the lowest note in the chord voicing. C E G B no matter how you voice it will be a Cmaj7. If the E was the lowest note, in pop-notation it would be Cmaj7/E, if it were G Cmaj7/G etc.

You are confusing different chords with inversions. You can put any note of a chord in the bass and it will still be the same chord.

Like Tim said, there can be exceptions, like in jazz sometimes they play chords lacking certain notes and you have to use your ear to figure out what note is the root, but C E G B is a straight forward Cmaj7


We tend to name chords for two potential reasons; to communicate the notes to play to another musician, or to analyse the harmonic progression of the piece.

The bass note is almost always the lowest note in the chord, when you consider all the notes played by everyone. It may not be the root note of the chord.

When you're trying to communicate, it's important to be as clear as possible. So we tend to choose the chord name that's easiest to read. We avoid using the bass note notation (slash chords), if there is a clearer alternative. Here's some examples:

  • Bb/G [G, Bb, D, F] should be called Gm7.
  • Em/C [C, E, G, B] should be called Cmaj7.
  • Fsus2/C [C, F, G, C] should be called Csus4.
  • C/B [B, C, E, G] should be called C/B, because it'll have some horrible name if you try and spell it as a B chord.

The simpler chords are easier to read quickly. There are some exceptions, but they are very much not the norm. Always choose the option that's the easiest to read.

If we're talking about harmonic analysis, we try and name the chord for its function. In that case, you might be a little less pragmatic. I'm not an expert here, and I don't think it's that relevant to your question, so I'm not going to say much here.

  • According to this my Eb/F is really good not like F7sus2+11(no5) or F7sus4+9(no5). Jan 16, 2017 at 14:31
  • 1
    @SovereignSun Yes, Eb/F is much clearer, so should be the preferred option
    – endorph
    Jan 16, 2017 at 21:03

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