Drop G on a 6 string: G-D-G-C-E-A
Drop G on a 7 string: G-D-G-C-F-A-D

Why does the note on the 5th string change?
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Some confusion might arise from the fact that you typed it out as if a seven string had an extra high string. Makes more sense like this:

6-string: ---G-D-G-C-E-A
7-string: G-D-G-C-F-A-D

What you're referring to as the fifth string, is actually the second string on a six string guitar and third string on a seven string. Strings are usually counted as the high E being the first. So, actually, every string is different, not only the "fifth".

If we get rid of the seventh string, we get this:

6-string: G-D-G-C-E-A
"7"-string: D-G-C-F-A-D

The interval between third and second strings is a major third. Since we count the strings as the highest pitch being first, you'll notice that the third string on the other tuning is C, and on the other it's F. This is why there is an F in the other tuning and E in the other.
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Can I clarify this for myself?

As I understand it, drop G tuning on a 6-string is G-D-G-C-E-A. That's essentially baritone register, with everything down 7 half-steps (and the 6th string down 9). I'm guessing that would need heavy gauge strings (maybe even bass strings for the bottom 3?).

If it's G-D-G-C-F-A-D on a 7th string, that means the top 6 strings are just 2 half-steps down from standard (DGCFAD in place of EADGBE), and the low 7th string is an octave below the 5th string (same as 6th string on the 6-string drop G).

Yes?
That is how I understand it, Jon. but I don't care much for low tunings.
Quote by Jet Penguin
Theory: Not rules, just tools.

Quote by Hail
*note that by fan i mean that guy who wants his friends to know he knows this totally obscure hip band that only he knows about with 236 views on youtube. lookin' at Kev here
Drop G on a 6 string guitar is a fifth lower than drop D = D A D G B E. Tune all strings down a fifth and you will get G D G C E A

Drop G on a 7 string guitar is a whole step lower than drop A = A E A D G B E (notice how the top 6 strings are the same as a 6 string guitar tuned to standard). Tune all strings down a whole step and you will get G D G C F A D (same as D standard + a low G string).

It makes most sense if you treat a 7 string guitar as a 6 string guitar with an added low string. (Well, Kevätuhri already explained this.)
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Last edited by MaggaraMarine at Oct 11, 2016,
Kevätuhri, jongtr, MaggaraMarine Thanks all, I understand now.
Last edited by CurrentlyOnFire at Oct 11, 2016,
Agreed with what everyone said above (lol)

-----
Basically, the low string would normally be A in both tunings:

7: ADGCFAD (looks like standard D with a lower string a fourth down as is normal between strings; A-D, D-G, G-C, C-F are all perfect fourths apart)

However, in drop X tuning*, the lowest string gets tuned a whole step/tone lower than normal to X, so the (low) A string gets tuned down to G in drop G.

-->
6: GDGCEA

* not to be confused with double drop X tuning, where the two outer strings get tuned down a whole step/tone. (example: EADGBE -(double drop)-> DADGBD (double drop D, D the resulting note)
Quote by Kevätuhri
That is how I understand it, Jon. but I don't care much for low tunings.
Never tried them myself. I mean, except when playing traditional old EADG bass guitar, that is...
The furthest I've ever gone on 6-string is a few modal C tunings. I have nothing against baritone tunings in principle, but it's too much of a hassle to fit heavier strings on my 6-string, and I'm not about to buy more guitars just to have some set up in those tunings. I guess - like you - I find the conventional range of 6-string has more than enough variety to offer as a solo instrument. And in a band I wouldn't want to step on the bassist's toes.
Quote by jongtr
Never tried them myself. I mean, except when playing traditional old EADG bass guitar, that is...
The furthest I've ever gone on 6-string is a few modal C tunings. I have nothing against baritone tunings in principle, but it's too much of a hassle to fit heavier strings on my 6-string, and I'm not about to buy more guitars just to have some set up in those tunings. I guess - like you - I find the conventional range of 6-string has more than enough variety to offer as a solo instrument. And in a band I wouldn't want to step on the bassist's toes.

Same for me. The lowest I'll ever go is Drop C or C Standard. I don't see the appeal on anything lower than that.
Having said all that, here's something neat:
I think the confusion has to with how the lowest string (the one being Dropped) in relation to the rest of the string. Let's look at your example of Drop-G on both a 6- and 7-string guitar.

The 6-String Variation

Let's keep in mind that on a 6-string, the tuning that you're in is usually referred to the lowest string. Standard tuning would be E-Standard (EADGBE) while Drop D would would be the strings tuned to E-Standard except for lowest being dropped down to D (DADGBE).

Taking this, we'll use your case of Drop G tuning. The "base" tuning would be A-Standard (ADGCEA); to make it Drop G, we would drop the lowest string down to G making it GDGCEA.

The 7-String Variation:

Let's go back to how 7-strings are regularly tuned from a guitar shop or from the factory. It would be this: BEADGBE. The best way to look at it is as E-standard with the 7th string tuned a perfect 4th below the E-string (making the B and E strings an inverted power chord). Most people would call it B-standard since they're used to referring to "standard" tunings by the lowest strings, but I tend to think of it as a 6th string tuning with extra bass strings.

To bring it into the case of Drop G, this is where it'll be different. The tuning for it's respective "standard" tuning on a 7-string would be D-standard ADGCFAD; tuning the Low-A down would to G would give us our Drop G tuning on the 7-string (GDGCFAD).

The Shorter Difference:

Think of only the 6-string tuning when going between 6- and 7-strings. On a 6-string guitar, you would start from A Standard and go down to Drop G; on a 7-string, you would start with D-Standard (with the 7-string tuned to an A, like between the top 2 strings) and go down to Drop G. The 7-string just adds an extra bass string to standard tuning, so that causes differences between 6- and 7-string "Drop tunings."

PS: Sorry for typing out a lengthy response. I like to explain things a bit to hopefully make it bit easier for others to understand things about the guitar.
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