(There's a bunch here, sorry. I've used bold text to outline the flow of the main content of the question.)
Basically, I'm transcribing the rhythms of a song, mostly in a 6/4 & 4/4 feel, though every now & then the music deviates into a small series of "glitchy syncopations," to put it one way. in the midst of all this, there's a single bar of 5/8 containing a normal (simple) quarter-note triplet (3 quarters in place of 2) followed by a single articulated 8th note. this got me wondering: if I used such rhythms in a composition which remained in 5/8 time extensively, and wanted to also incorporate a triplet which spans the entire 5/8 bar (a slightly more complex tuplet) how would I notate that?
The answer seemed simple at first to me: use 3 beamed eighth notes, spaced appropriately, topped with the ratio notation: 3:5. this indicates that there are 3 eighth notes in place of 5? correct?? (see image below)
However, when this figure is compared to the "simple" quarter note triplet mentioned before, there's a possible discrepancy in clarity concerning speed / duration: aside from the differences between note spacing of the components within each triplet, the 3:5 triplet in bar 2, below, (which SHOULD represent a slower/longer triplet than the one in bar 1) suggests that it is faster than the standard quarter-note triplet. which is fully untrue, and seems a tad too misleading for my liking.
Am I missing something crucial? like... if the meter is odd / imperfect / irregular, are the rules for notating tuplets altered? in other words, is my notation of the first, simple quarter-note triplet wrong? and is that notation (three quarters with a bracket) better suited for the triplet which spans the entire 5/8 measure?
Off the top of my head I know of one source: Alexander Scriabin's Prelude in C (Op. 11 No.1): the meter is 2/2, but the general feel is a subdivision of quintuple eighth-note groupings, accents often notated and implied on the 1st and 3rd notes of each quintuplet. The composer never uses tuplet symbols to indicate that 5 eighths take the place of 4 (at least in none of the scores I've seen) but the music makes the subdivision quite clear.
Anyways, in a few places the left hand plays a figure of 3 quarter notes, again, never notated with any tuplet signs, but implied to be a triplet pitted against the quintuplet: 3 quarters in place of 5 eighths (aka a normal quarter-note triplet pitted against the standard pulse of the time sig: 2/2), rather than a quarter note triplet taking the place of 4 out of 5 of the eighth-notes from the quintuplet... or any other rhythm. the distinction between these triplets may seem slight but I believe it makes a difference which one is observed.
I realize since the time signature is 2/2 and not 5/8, there may be a difference between this example and my hypothetical, but if my assumption about Scriabin's triplets here being 3:5 is correct, then my very first posited notation of the "simple" quarternote triplet in a 5/8 context may be fallacious, and I should be treating said "simple" tuplet with a more special approach. maybe the following:
Using the 8th-note triplet, explicitly labeled with a "3:4" ratio (above left), instead of the standard quarter note triplet notation, seems a clearer solution. its result is the same as (quarters)3:2 but leaves room for the usage of the 3 quarter grouping to represent triplet which fills the duration of a 5/8 bar, like my assumption of Scriabin. (above, right
One more possible notation:
Is this just one of those kinks in our system of notation? or is there a ~standard protocol based on precedence in sources? If you've read all this thanks so much.