# When using Functional Chord symbols, how can we distinguish between a Dominant 7th chord and a Major 7th chord? [duplicate]

In the key of F major (for example), we can have the chords C7 and Cmaj7.

C7 = C-E-G-Bb and Cmaj7 = C-E-G-B

Using Functional Chord symbols, the basic tonic chord is "I", and the basic Dominant chord is "V".

How should we distinguish between a Dominant 7th chord (i.e. C7) versus a Major 7th chord (Cmaj7) using the Roman Numeral Functional Chord Symbols?

• It is actually answered here: Difference between V7 and Vmaj7 chords? music.stackexchange.com/questions/94401/… So this topic should be closed as a duplicate question. – Lars Peter Schultz Mar 21 at 22:29
• It is the same subject matter, but under the surface, the earlier question seems to be asking and answering why RNA doesn't represent chord quality, and OP's new question is asking specifically how to use RNA to distinguish between chord qualities. Vote how you will, but in my opinion they seem barely different enough to coexist as valid questions on this site that provide different information. – user45266 Mar 22 at 1:25
• @user45266 the earlier question in the link I provided clearly answers the question how to distinguish between a Dominant 7th chord (i.e. C7) versus a Major 7th chord (Cmaj7) using the Roman Numeral Functional Chord Symbols. There is even an answer in the headline of that link. – Lars Peter Schultz Mar 22 at 7:10
• @LarsPeterSchultz While I agree that your link does provide a solution to this question's presented problem, I'm not entirely convinced that it provides the only answer... I'll try to explain my logic: – user45266 Mar 22 at 10:09
• OP's question asks "How to write RNA in a way that distinguishes between the 7 and maj7 chord qualities?", and your linked question is "In a mix of RNA and jazz chord symbols, what is the difference between the 7 and maj7 symbols?" Those are very similar questions, but your link is describing one particular notation system that does happen to work to provide a solution to OP's question. But I don't believe that the answers given in your link are a comprehensive enough answer to this question for this question to be rendered a duplicate of the one you have suggested. – user45266 Mar 22 at 10:13

## 3 Answers

In key Fmajor, the only diatonic chord out of the two is C7 - C dominant 7. Cmaj7 isn't there. It is in key C major, but that's not part of the question.

Using RN, in key F, V (or V7) is C7 (C E G B♭), so Cmaj7 would not (in my experience), be a chord that would rear its head.

• Just to add and clarify, there ARE two maj7 chords in any major key but they are the I and the IV. In F that’s Fmaj7 and Bbmaj7. – John Belzaguy Mar 21 at 22:26

In the key of C major, Cmaj7 would be I7. C7 is a bit trickier, but in almost any role it is being used in, it should be written as V7/IV. That way, it is obvious that the Bb is present rather than the B, and it also is representative of the chord's function - the V7/IV chord wants to go to the IV chord (F), where I7 (Cmaj7) is a tonic chord and very comfortable where it is. But that's only for the key of C, where C7 has an easy functional label. Roman Numeral Analysis was built for functional harmonies (see final paragraph for details), and thus it doesn't do nearly as well with non-functional chord sequences. So how would we go about doing this in F, or any other key where the two chords don't lend themselves to functional analysis?

The following workaround is not consistent with how the Roman Numeral Analysis was originally formatted, but you could also decide to always use 7 for chords with a minor seventh interval and specify maj7 if the major seventh is present (the I chord then being Imaj7, rather than just I7). This is consistent with how modern chord symbols address the issue, however.

For another potential idea, recall that much of Roman Numeral Analysis draws from the old tradition of shorthand Figured Bass notation, and the "7" symbol in Figured Bass comes from the intervals above the bass note: spelled out fully, that would be (7 5 3), but shortened to (7). Figured Bass symbols referred to diatonic notes by default, and so does RNA. When FB wanted to represent a non-diatonic note, it would be written as an accidental (there were many methods of marking chromatic alterations in FB, but let's stick to the accidental symbols for their contemporary relevance). In Figured Bass shorthand, in a minor key, (6 3#) meant to play the note which was a third above the specified bass note, but raise it one half-step, while also playing the note a 6th above the bass note.

So in F major, Cmaj7 could be written in FB as (#7) with the C specified as the bass note. Interpreted into English, this reads "play the intervals of a diatonic third, diatonic fifth, and raise the note that is a diatonic seventh above the bass by one half-step". This would not be standard in traditional Roman Numeral Analysis, but FB chromatic alteration notation applied to RNA chord inversion symbols could be a logical solution to the problem as long as it was understood correctly (and bonus points for historical accuracy).

There are still some situations in music where this would not solve the ambiguity, but be advised that if one is running into many ambiguous notation scenarios while using RNA, well... why use RNA in that case? The RNA system was built around functional harmony, and using it for nonfunctional analysis is inefficient. RNA doesn't have to explicitly encode the quality of the seventh, because the idea of reference to a key center is baked into the RNA system, allowing RNA to simply designate diatonic notes and denote other notes as alterations. In contrast to this, modern chordal symbols were designed to always be unambiguous independent of harmonic context. This is why Roman Numerals can break down outside of clear functional harmony: the RNA symbols have a hard time working around muddied or unclear key centers because they were optimized for analysis of tonal harmony.

If we are in the key of C then CM7 is I7, while C7 is the secondary dominant of F (V7/IV). Example: Violin concerto Am by Bach 2nd movement andante.

So if we are in F:

C7 = V7 (dom7)

and when a CM7 occurs (e.g. in a fifth fall sequence) there will be an extension or modulation to the key of C and we will analyse I7. (e.g.Bach Inventio 8 in F).

A special case is the Blues where we always mean: b7

when writing I7 or IV7 (like V7).