What is an altered diminished chord?

I was playing today exploring some new chords in G minor and accidentally found a really beautiful chord, and when I searched it on google I found that it is called: F#dim6(b13,no5).

This confused me as I had no idea there was such a thing as altered diminished chords.

So far in my understanding, as soon as I alter a diminished chord it automatically turn into a minor7 or a dominant7. How come this F#dim6(b13) didn’t?

The chord is played like this:

Thick E-string: 2nd fret
D-string: 1st fret
G-string: 3rd fret
B-string: 3rd fret

• I agree with you this doesn't make sense. To best answer your question, perhaps you could include a link to where you found this chord reference. A look at that page might help figure out what is meant. Commented Jan 28, 2022 at 22:31
• Hmm... This makes even less sense now knowing the notes you're playing (G, Eb, Bb, D), since there is no F#. Commented Jan 28, 2022 at 23:26
• I don't know what an altered diminished chord is, but your chord is Ebmaj7/G. Commented Jan 29, 2022 at 0:49
• @piiperiReinstateMonica Altered Diminished Chord: n. A diminished chord on acid? Commented Jan 29, 2022 at 1:17
• @Aaron I put it in an answer. I tried to think, "why did this question come up, and what would the OP have had to do in order to not have this question". Kind of like, what's the real question behind this. Commented Jan 29, 2022 at 1:20

2x133x is a Gb Lydian augmented chord

In the context of Bb or G minor key, it's Gb6+5 or Ebm maj7 / Gb. The 2x133x chord does a bit of modal interchange, bringing in stuff from Bb major's parallel minor key Bb minor. If you switch between x1323x and 2x133x, it's a nice Pat Metheny'ish ending vamp.

If you're into chord=scale=mode thinking, then I'd say that 2x133x chord is like the third mode of the Eb melodic minor scale, or Gb Lydian augmented chord=scale=mode. Compared to Bb major scale that has Bb and Eb, when the 2x133x chord is sounding, you'll have Gb and Ab as additional flatted notes.

Here's a short tune which uses the chord to end in Bb major:

Notice how the outside-key sixth Gb-Eb resolves back to inside-key sixth F-D ?

• I wrote wrong. It should be: 2x133x
– j a
Commented Jan 29, 2022 at 8:27
• i think you answered my question. could it be that i was actually playing in melodic minor without realizing it? i thought i was playing in G-minor. but since i was experimenting i could easily have been mistaken. i actually just started learning about harmonic minor and melodic minor just recently, and i understand their chords are way different from major or minor families. and yes it definitely reminded me of pat metheny, thats why i was so intrigued to learn more because I really love his playing. i
– j a
Commented Feb 18, 2022 at 0:52
• @ja If you think you're playing "in a mode" or "in a scale", then you are. Otherwise you aren't. This is the difference between chord=scale thinkers and others - IF they think about every chord "being" some scale, then the chord=scale theory is a useful way for trying to understand and describe their thinking. But if they think, say, in terms of visual fretboard patterns, then some other description style could be better. Whether you're "in G minor", depends on how you feel and think about it. Also keep in mind that scale degrees change in modal interchange - now it's flat, now it's natural. Commented Feb 18, 2022 at 9:17

Identifying complicated chords out of context is a bit academic, but if you root 2x133x on F♯ or G♭, it’s definitely not any kind of diminished chord. By definition, a diminished chord is built from stacked minor thirds resulting in a minor third and flat fifth. By rooting the chord on F♯ or G♭, you’ve got a major third (in the form of A♯ or B♭, respectively) and you’re missing the fifth altogether.

While it’s common to eliminate the fifth when you have a crazy chord with extensions or altered extensions—the fifth is there as a strong harmonic of the root, anyway—you really can’t do it with augmented and diminished chords without changing their core quality.

Augmented chords are built from stacked major thirds, and that’s what you’ve got here if you treat the D as a ♯5. Between G♭, B♭, D, and E♭, it’s G♭+6 in root position.

Without context, an augmented sixth chord can also be analyzed as a minor major seventh chord, so you’re right that it could be called E♭mmaj7 in first inversion.

FYI, I used this website (of my own design) to explore all the possibilities.

• The OP did give some context, the key is G minor. Isn't that a lot of useful context already? The 2x133x chord clearly performs chromatic alterations to the basic scale of the G minor context. Click, click, the sharp/flat/natural switches on scale degrees move to different positions. Commented Jan 29, 2022 at 11:20
• The OP also made it clear that this chord was stumbled upon. It’s clearly chromatic, yes, so what to call the chord depends a lot on what comes before and after and no progression was given.
– trw
Commented Jan 29, 2022 at 11:45
• The stumbling happened in the context of G minor key. That should be enough to make a good guess at least. I'm a strong proponent of listening, as opposed to googling and calculating. If G minor is not enough context and makes the question academic, then I don't know what it is if you take the answers from some calculator. Engineering? Commented Jan 29, 2022 at 18:23
• You wrote an answer based on an assumption of context that I don’t think is there, or is at best tenuous, considering the OP’s confusion over what makes a diminished chord a diminished chord, so I wrote an answer from a different point of view. You seem quite upset over the use of a tool that can assist in analysis and learning. I don’t understand what you’re trying to get me to concede or correct.
– trw
Commented Jan 29, 2022 at 21:07