(music theory question) lydian, diatonic yay or nay?

(music theory question) lydian, diatonic yay or nay?

I read something interesting on Wikipedia under the definition of the word "diatonic": "… A diatonic scale can be also described as two tetrachords separated by a whole tone…."

Now the lydian mode has a half step between its tetrachords so it wouldn’t be accepted by the definition above and yet the lydian mode IS regarded as a diatonic mode so how does it work please?

Thank you

Re: (music theory question) lydian, diatonic yay or nay?

A diatonic scale is two tetrachords thus (in ‘D’ for convenience):
D E F# G (four notes a perfect forth apart)
And
A B C# D (also four notes a perfect forth apart)
Each mode starts with any note of this scale of two tetrachords.
Lydian would be rooted on G (G A B C# D E F#).
Therefore diatonic.
All ‘normal’ modes are.
Of course when any chromatacism is introduced to this modal process the theory gets a little more complex!

Re: (music theory question) lydian, diatonic yay or nay?

Trying to say it more clearly (because I had to read Yhaal three times before I realized he was absolutely correct):

Suppose you have a one row accordion which can only play notes in the scale of D major.

Then you can play a lydian scale on the accordion by starting on the note of G. Every note will be from the D major scale, but since you start at a different point, it doesn’t map exactly to the "two tetrachords separated by a whole tone" thing. That is, that pattern is still there in the notes, it just doesn’t match up with the start of the scale.

Re: (music theory question) lydian, diatonic yay or nay?

The problems of mixing scales and modes, and not recognizing the difference between a scale and a key. Lydian mode isn’t a diatonic scale because it isn’t a scale, it’s a mode.

A scale is just a circle of repeating notes. A diatonic scale is a circle of seven notes generated by consecutive perfect fifths. But importantly a scale doesn’t have a tonal centre - it doesn’t matter what note you start from, if you take eight steps round the circle you land up back where you started. But a key and a mode also specify a tonal centre. So if you take the diatonic scale built on D and start playing on the D (thus giving it D as the tonal centre) it’s D major. Start on B and it’s the key of B minor, start on G and it’s G lydian mode, but in each case it’s still the D diatonic scale. Technically lydian is a diatonic species, because it uses only the notes of a diatonic scale, but it isn’t a diatonic scale.

Re: (music theory question) lydian, diatonic yay or nay?

Excellent contribution thank you

Re: (music theory question) lydian, diatonic yay or nay?

Not quite sure how that "circle of seven notes generated by consecutive perfect fifths" works, Mark M.
I can see how if I start with, say, C I’ll get G - D - A - E - B - F#, which gives the notes of G major, but the F# doesn’t lead back to C and, with perfect fifths, it never will (it will get to B# with is close to C but not the same if the fifths are perfect) so not sure how the circle is completed.

Re: (music theory question) lydian, diatonic yay or nay?

It’s not a circle of fifths, only the first part of it. It is seven notes generated by consecutive fifths, (six of them, not seven, sorry) and then transposed down into alphabetical order. So starting from C you get C, G, D, A, E, B, F#. From there you don’t keep adding fifths, you transpose into alphabetical order giving C, D, E, F#, G, A, B, the notes of the G diatonic scale. From there you can arrange them in a circle (or keep repeating the pattern for higher and lower octaves.) From there, by starting on different notes you can generate all the G diatonic species - keys and modes that use the notes of the G diatonic scale. It is the same process and generating the chromatic scale from the circle of fifths, but only using the first seven degrees.

Re: (music theory question) lydian, diatonic yay or nay?

Thanks for the clarification, Mark.

Re: (music theory question) lydian, diatonic yay or nay?

Wikipedia is known for being mediocre when it comes to music theory. "Two tetrachords separated by a whole step" describes the diatonic MAJOR scale, but not ALL relative diatonic scales. The spacing of "two tetrachords separated by a whole step" stays the same for all diatonic modes, but doesn’t line up with the tonic of each mode. Lydian is definitely diatonic, if there are no other accidentals involved.

Re: (music theory question) lydian, diatonic yay or nay?

Does anyone have any examples of tunes in the lydian mode? Was looking to see if I could find any but I couldn’t find any lydian in the key/mode selection wheel in the search engine of the tunes section…

Re: (music theory question) lydian, diatonic yay or nay?

David L, Wiki is right on this one, a diatonic scale is always two tetrachords separated by a whole tone. The notion of a major diatonic scale is erroneous, because major and minor refer to keys, not scales. A scale is just a collection of notes, it doesn’t specify a tonic, so D major, B minor and G lydian are all the same (D diatonic) scale. Lydian is diatonic, but it is a diatonic species, not a diatonic scale, i.e. G lydian is a species of the D diatonic scale (which is the two tetrachords separated by a tone).

Re: (music theory question) lydian, diatonic yay or nay?

To construct the major scale from the fifths just start a fifth below the tonic F natural then it all follows nicely to give all the seven notes

Re: (music theory question) lydian, diatonic yay or nay?

"To construct the major scale from the fifths just start a fifth below the tonic F natural then it all follows nicely to give all the seven notes"

Except that the intervals aren’t always true when constructing a scale this way. If you start on F (the fifth) and keep producing notes by adding perfect fifths in the ratio 3:2 then the ratio between E and C will be 81:64 rather than 5:4 (80:64). So the third of the scale will be 1.25% sharp which is slightly worse than equal temperament.

Re: (music theory question) lydian, diatonic yay or nay?

Looking at it another way if you start with a note, say D, and then take the four simplest whole number ratios from that you get F#,G, A, B and D (not in that order). Those are the most consonant notes with the D.

That leaves two large gaps which is not very ‘general purpose’. The four semitone one you spilt roughly half way (E). The other is three semitones and how you split that gives you either the two tetrachords separated by a tone (C#) or a scale with a flat seventh (C natural).

Re: (music theory question) lydian, diatonic yay or nay?

I have recently decided that I will call something whatever I want as far as music theory is concerned. What I will not do however is to make this practice known outside my head, unless I want to lose it. A friend with whom I play for dancing, must always be using the correct terminology. Eg she does not play a melodeon, but a diatonic, button accordion. She is a lovely person, bless her, so I just let whatever she tells me flow in one ear and out of the other, while remembering enough to keep up my end of the conversation. I know how the tune goes, so I simply don’t worry about what mode it is in, but just "play that thing" as Johnny Dodds put it.

Re: (music theory question) lydian, diatonic yay or nay?

That’s interesting David50 thank you!

Re: (music theory question) lydian, diatonic yay or nay?

Mark M, I well understand what diatonic means. Yes, D major, B minor, and G lydian all share the same scale. You call that the "D diatonic scale", even though the D note is found in many diatonic scales. You are naming it by the major iteration. I did the same by calling it the diatonic major scale. B (natural) minor is the same diatonic minor scale. By the way, there is nothing special about the major iteration, so calling it the D diatonic scale doesn’t really describe it, unless you mention that it is the D major iteration.

Re: (music theory question) lydian, diatonic yay or nay?

No, I’m naming it for the root that the scale is built upon. The D diatonic scale is two tetrachords with a whole tone between, starting from D (which is why it is called the D diatonic scale). Starting from the twelve tone chromatic scale, which encompasses all keys and modes, you can construct twelve diatonic scales, each named for the starting note - the lowest note of the lowest tetrachord. But these are still just scales, just endless series of notes, they have no implied harmony, so cannot be thought of as major or minor. Within each of the twelve diatonic scales you can produce any key or mode depending on which note you pick as the tonic. It just happens that if you pick the tonic as the same note the scale is built on you produce the major key, but the scale is named first, you are not naming the scale after the key.

Re: (music theory question) lydian, diatonic yay or nay?

"Does anyone have any examples of tunes in the lydian mode?"

Whenever this mode is discussed, Richard Cook brings up a few examples (from the Scottish piping tradition).

Re: (music theory question) lydian, diatonic yay or nay?

And at least one from the Irish piping tradition! Borrowed from the Scottish, people say.

BTW it’s more than a few tunes in Lydian in the GHB world, because there are numerous old tunes, and new ones are being composed in that mode all the time. You hear that mode often in the GHB world and those tunes don’t attract any special notice from pipers. Highland pipers generally don’t think in terms of keys and modes anyhow, which makes it difficult to calculate how many Lydian tunes there are. GHB tunes aren’t listed or organised by key or mode (at least in any GHB collection I’ve seen.)

But it’s not only that. As I’ve mentioned I was amazed when I heard two Irish fluteplayers (both visiting the USA from Clare, as I recall) play quite a few tunes together. Very good players. The amazing part was that the note C natural evidently didn’t exist for these guys, which changed the tonality of many tunes.

All of the tunes that are generally heard in G Major, at least the tunes which include the fourth degree, were rendered in G Lydian.

Oddest perhaps was Rakish Paddy, generally in C Lydian, but now having its tonic raised to C# (without raising any other note).

Re: (music theory question) lydian, diatonic yay or nay?

I don’t want to get into a fight but I have always understood Rakish Paddy to be D mixolydian. Same set of notes obviously, it just depends on which note you consider the tune to be built on. If I play it by itself, I suppose I might start and end on C, but I would probably add the open D string below it, and if I was playing piano instead I would end on a D no 3 chord. Ending the melody on C would give the tune a more unstable ending anyway, like when you play an A tune and then end on the D and A string together. You could also just end Rakish Paddy on a D chord.
That there are so few Lydian tunes in the Irish tradition is a favorite topic of mine. I consider it to be a feature of the language, like that there is no sh in Spanish or ch as in loch or bach in English.

Re: (music theory question) lydian, diatonic yay or nay?

I agree, Rakish paddy is in D mix , it resolves to D , just like we assume to be it’s Scottish predecessor was in A mix . I don’t think there are any Lydian tunes in either reportoir , Scottish or Irish.
Other suggestions to further a debate?

Re: (music theory question) lydian, diatonic yay or nay?

Richard, are there any recordings of a particularly Lydian setting of Rakish Paddy (or Caber Feidh)? What about the written settings?
https://thesession.org/tunes/86

Anyone? All of them? Is it the mere shift from C to D that triggers the Lydian feeling, or is it something else? (I just hear it as a Dmix tune which happens to start on the C chord.)

Re: (music theory question) lydian, diatonic yay or nay?

My take on Rakish Paddy is that it modulates between C lydian and D ionian (or possibly mix). One surefire way to find the tonal centre is to put a drone under the melody. In this case there isn’t one note that fits the whole tune, you need a C under the first two bars and a D under the second two, and they keep alternating.

Re: (music theory question) lydian, diatonic yay or nay?

D7 fits fine instead of a C a lot of the time ….. through with caberfeidh there’s a lot of G ma j arpeggio (in their respective keys Both I and VII and I7 )
Although I don’t agree that it modulates between C Lyd and D mix it’s an excellent suggestion and that kind of ambiguity is rife in the tradition so it’s quite reasonable and possibly so . With pipe tunes the drones should be taken into account so even if it’s a C in the melody it’s surrounded by three octave of D !!

Re: (music theory question) lydian, diatonic yay or nay?

In Norwegian trad music you can find a number of lydian tunes.

Re: (music theory question) lydian, diatonic yay or nay?

Mark M, the classical definition of "diatonic" is a 7 note scale with two half-steps being as far apart as possible. The is no mention of a "root" note or name for a diatonic scale. There is no bias toward the ionian version. They are not "named" for the ionian tonic. A diatonic scale is not "built" on any particular root.

Re: (music theory question) lydian, diatonic yay or nay?

As you say, there certainly is no bias towards the ionian, and they are not named after the ionian tonic. That is the very point I made several posts ago when you were claiming they were named after the major key they contain.

However, a diatonic scale IS built on a particular root. If you start with the 12 tone chromatic scale, (which is a single scale containing all the diatonic scales and all the possible keys and modes) The chromatic scale has no beginning and no end, just a series of notes stretching from down where the earth shakes to up where the dogs can’t hear it. If you gap that scale with a TTSTTTS sequence you produce a diatonic scale. It still has no starting note and no ending note BUT depending on how the gapping sequence lines up with the chromatic scale we have twelve different diatonic scales, and for convenience we label them according to the note the TTSTTTS sequence starts on, but that label or ‘root’ doesn’t tell you anything about which note you should start playing on, or how you should harmonize the scale. Within each diatonic scale no one note is favoured over the others, you still have seven possible starting points. It is only when you choose one note as your starting point or tonic that you define the mode or key.

Re: (music theory question) lydian, diatonic yay or nay?

The diatonic pattern can be TTSTTTS, but it can also be TTTSTTS, TSTTTST, TTSTTST, STTSTTTS, STTTSTT, or TSTTSTT. There is nothing special about TTSTTTS and it does not "name" the diatonic scale, at least not in any music theory book or music dictionary (including Grove’s) that I have ever seen.

Re: (music theory question) lydian, diatonic yay or nay?

If they are named, how are they named?

Re: (music theory question) lydian, diatonic yay or nay?

Those are all exactly the same sequence of intervals, just starting from different positions. They define the mode but not the pitch (i.e. which diatonic scale they are applied to). A simple definition of a diatonic scale is ‘all the white notes on a piano, or any transposition of them’. Naming the scale tells you how far they have been transposed (with C being all the white notes.) Applying all your sequences starting on C gives you all the modes of C, but they are not all on the same scale - they all require some black notes. However, if you play seven white notes starting on each successive white note you generate all seven modes on the same scale, the one we call C.

Re: (music theory question) lydian, diatonic yay or nay?

FWIW I very often play Rakish Paddy droning the open D under the first two bars. It’s definitely what you would hear were you to play the tune on uillean pipes, as well.

Re: (music theory question) lydian, diatonic yay or nay?

I don’t know Rakish Paddy well, but I have been playing Caber Feidh for a while. Many GHB tunes are regarded as being "doube tonic", i.e. they often start with with two bars in A major (i.e. built around the notes A, C#, E) followed by two bars in G major (G, B, D), then back to A, then to G and so on (the two bar phrases can include passing notes outside the triads). A good example is The Inverness Gathering. Caber Feidh fits this pattern, but it’s unusual in that instead of starting in A, it starts with two bars in G, then goes up to A, down to G and so on. So even though it uses the notes of the A mixolydian scale, the tonality seems to be G. I think that regarding it as diatonic is more helpful than thinking of it as lydian.

Re: (music theory question) lydian, diatonic yay or nay?

Of course, one way of thinking about double tonic tunes is that they are (IV)-V-IV-V-IV-V-etc and never resolve to I, or modulate elsewhere.

(though I wouldn’t apply this logic to Rakish Paddy, which I’d consider very clearly Dmix)

Cabar Feidh is a good example of a tune that has to some extent been bastardised in order to fit on the pipes, but the bastardisation has taken on a quality all of its own. That third part with the C# is wrong in every sense, yet we’re so used to it in such an iconic tune that you couldn’t dream of doing away with it.

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Re: (music theory question) lydian, diatonic yay or nay?

A diatonic scale is a scale that can be played on a diatonic instrument without any of the fancy effort to get accidentals (fancy fingering/half-holing on the whistle or keyless flute, bending on the harmonica, pliers and file on the one-row melodion). On a D melodion, if you were to try to play a G major scale, you would be perplexed and confounded by the fact that there is no C-natural.

If you want to play tunes in G major on that instrument, you can:
- transpose the tunes to D
- only play G pentatonic tunes that avoid scale step 4
- play something harmonically pleasing when the C natural rolls around so your fellow session members don’t kill you
- play the C sharp when everyone else is playing C natural (quite popular in Quebec, and part of the joyful sensibility of that province’s music)
- play tunes in G Lydian mode
- play tunes in G that only feature C sharps as chromatic lower neighbors to scale step 5

I do want to quibble with the assertion that diatonic modes are two tetrachords (agree) separated by a whole tone (disagree).

Lydian based upon a D-major-native instrument has the lower tetrachord (G A B C#) separated from the upper tetrachord (D E F# G) by a half step (C# to D). Still diatonic. Still a mode. Also phrygian mode lower (C# D E F#) and upper (G A B C#) tetrachords are separated by a half step (F# to G), but are still classical modes on the diatonic scale.

There are quite a few pure Lydian tunes in the quebecois tradition, mostly written by box players in G, but embraced by fiddlers that don’t particularly like to spend too much time with lowered second fingers.