i was messing around trying to write a weird chord progression and i came across something i hadnt seen before. i played an E7 chord on the guitar but i played a D# on the b string, so the fingering would be 02014x. Sibelius' chord namer comes up with "D#maj7b9#5sus4/E" which is technically right, i suppose, but it feels more like an E chord. is there a chord name for something with a major 3rd, minor 7th, and major 7th, or is this too dissonant for a name to have been given to it yet?
Learners often seem to think that there is a one-to-one mapping from collections of notes to chord names, but it isn't so.
For simple chords this might be a reasonable enough position, but things get more complicated quickly. To take a couple of simple examples, consider a G13 chord (G B D F A C E). The same collection of notes might also be called a CMaj13 (C E G B D F A). It might instead be called an FMaj13(♯11) (F A C E G B D), or it might be called a Dm13 (D F A C E G B). Or consider an Fm6 chord (F A♭ C D), which contains the same notes as a D∅ chord (also called D half-diminished or Dm7(♭5): D F A♭ C).
So, how do you go about naming these chords? You have to look at the harmonic context in which the chords appear. If you are playing in a functional harmonic context, you need to look at how the chords are functioning. A chord containing the notes D F A♭ and C is probably a D∅ if you are playing in the key of C minor, especially if the chord following it is some type of G7 chord. On the other hand, if you are playing in the key of E♭ major there is a good chance that this chord is an Fm6, especially if the next chord is some type of B♭7 chord.
For the chord in question (E G♯ B D D♯) there is no common name. An option would be to consider this as its enharmonic equivalent (E G♯ B C𝄪 D♯, where C𝄪 = C♯♯) and to call it an Emaj7(♯13). Maj7(♯13) chords aren't the least bit common, so players may not be able to find a voicing quickly although they would know what you meant with this name. Since you found this chord by altering an E7 chord, it seems suspicious to me to name this alteration as an EMaj7 chord.
The chord itself is a hybrid of an E7 and a EMaj7, and you could name it based on how it is functioning when it appears. If your chord precedes an A or Am chord, it is probably functioning as a V chord, so it should probably be called some kind of E7 chord: you might as well just call it an E7(add 7), or E7(add ♮7), or E7(add D♯). If your chord follows some type of B7 chord it may be functioning as a I chord, and you could call it an EMaj7(add ♭7) or EMaj7(add D).
Slash chords are often used to communicate chords which are difficult to name using the standard nomenclature. Using this approach you might try B6(add ♯9) / E (E B D♯ G♯ C𝄪, omitting the 5th). One of the ideas behind slash chords is to name unfamiliar chords in terms of simpler chords, or at least in terms of more familiar chords. B6(add ♯9) / E doesn't seem like much of an improvement over EMaj7(♯13). Another option would be B13(♯9) / E (E B D♯ G♯ A C𝄪, omitting the 5th and 11th). This is pretty compact, and B13(#9) is fairly common. It is common to omit the 5th and 11th of a 13th chord, but you can't omit the 7th, so the A needs to stay. That means that this chord contains a note that was not in your original chord. If I was trying to name this chord I would decide if I wanted to include an A or not. I might even notate it this way and just not bother with playing the A.
If your chord shows up in the context of an E7, and the D♯ is just a note from the melody, I would just call it an E7 and be done with it. Similarly for an EMaj7 with a D just passing through.
All of this to say that there really isn't a simple answer to your question of how to name your chord. To some extent the way we name chords is personal, and you will find that chord charts can differ and still be correct. But for me your chord is something of a hybrid, and the name will depend on the context, and the way you voice the chord. The way you played it (02014x), and in the absence of other information, it sounds like it wants to be some type of EMaj7 to me, so I would probably call it an EMaj7(add ♭7). You could also play it as (02113x), which sounds like it wants to be some type of E7 to me. For this I lean towards B6(add ♯9) / E. But in the end it is up to you to decide how to best name the chord to communicate your intentions.
I always try to preach that chord labels should show how they function. It's hard for me to imagine a collection like this actually functioning like a chord with major and minor seventh, but assuming such a case exists, here's a thought:
Some analysts discuss the notion of a "split third" chord, where a harmony includes both a major and a minor third. For instance, the collection
D F F♯ A would be a "D triad with split third." (Some label that as
D!, with the exclamation point, but that always just seemed funny to me.)
The point being that you may choose to call this a "split seventh" chord.
All Western harmony can essentially be be broken down into 3 major components: tonic, dominant and subdominant. Tonic chords are the “home” sound of the key. In a major key, these are the I (root), iii and vi chords, the last of which is equivalent to the i chord of the relative minor key. Dominant chords provide resolution back to tonic chords, and are typically the V and vii-diminished chords. Finally, subdominant chords “prepare” the aforementioned resolution, and usually come before dominant chords. In major keys, these are the ii and IV chords. We can analyze your chord through these principals.
You said you’re playing some kind of E shape with both a major and minor 7th, along with a G#, the major 3rd. I’d agree that the root of the chord is E, as we typically consider the bass note to be either the root, 3rd or 5th of the chord; and if “E” was anything other than the root here we’d have a truly “outside” chord to write.
Since E is indeed the root, that means we have a chord with both 7ths, major and minor, present. However, this kind of chord does not fit into any of the defined categories of Western harmony, as the major 7th of a key is used either for color (being the major 7th extension of the root chord), or, more commonly, the leading tone of the key that resolves back to the root in a melody. Likewise, a minor 7th in a chord acts as a resolution to the third of the following chord in the current or new key. As you may have discovered, having both of these tones simultaneously creates an issue because neither 7th can perform its function.
So what is the chord? I’d classify it as atonal, or a cluster of sound. Again, since both 7ths are in the chord it would be difficult to say that your chord is a polychord, as most polychords are made up of two distinct triads or seventh chords, which is not the case here. Some might say, incorrectly, that this is an Em(maj7) chord, but that isn’t possible either because that chord is built from an ascending melodic minor scale, which does not contain a minor 7th. Really, you could argue all day about what kind of sound you have here, but I think it would be helpful for most musicians, chiefly those who are still learning the fundamentals, to think of chords in the three major categories accepted by Western musicians.
Frankly, when you start trying to analyze chords based on abstract extensions and theoretical harmony you tend to muddy the chords’ functions, which trump everything else. All chords can really be broken down into those three major categories - even in complicated jazz progressions - which are the absolute foundation of Western music.
The dissonance in this chord/voicing is strong medicine, but 'modern jazz' guitarists in particular have been milking it, either in passing, or to build tension, for at least forty years.
For analysis, you could go with Dasia's answer; for accuracy, you can't go past notation, but for writing a chart in the hope that a guitarist will recognise it on the fly, maybe that B13(#9)/E is the most player-friendly.