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3/4 vs. 3/8 vs. 6/8 vs. 12/8 etc.

Discussion in 'General Instruction [BG]' started by oniman7, Aug 26, 2012.


  1. I consider myself fairly knowledgeable ibn music theory, but similar time signatures have always tripped me up.

    Say for example that I'm playing a riff in 3/4 at 120 BPM. Couldn't i play that same riff in 3/8 at 60 BPM and have it come out the same?

    And 3/4 vs. 6/8... they both accent the third note, right?

    A little help would be great...
     
  2. Pacman

    Pacman Layin' Down Time Staff Member Gold Supporting Member

    Apr 1, 2000
    Omaha, Nebraska
    Endorsing Artist: Roscoe Guitars, DR Strings, Aguilar Amplification
    For this type of example, yes.

    No, 3/4 the metric stress is on the first note. 1 2 3 1 2 3. For 6/8 the metric stress is on the 1st and 4th notes 1 2 3 4 5 6. This of it like this, 3/4 is a waltz feel, but 6/8 is in two, but each beat is a triplet (1 and ah 2 and ah)
     
  3. Jazzkuma

    Jazzkuma Supporting Member

    Sep 12, 2008
    It usually has more to do with the phrasing, harmonic rhythm and feel. Sure it might sound the same if you count one way or another (without accenting) but an afro cuban groove will usually be 6/8 instead of a very fast 3/4 for a number of reasons (phrasing, harmonic rhythm, ease of playing/reading and feel). When you dance to afro cuban 6/8 you dance in two and not a very fast three (that would look and feel very weird).

    Same way as enharmonics, sure a B natural is the same as a Cb but we use them in different situations. Cb when spelling out the scale and its respective degree (and usually in classical) but if you are reading a chart or are at a gig then most of the time they will write a B natural for easy of reading.
     
  4. Those would still be accenting every third note, I think...

    But if I'm reading you correctly, 3/4 is a feel based on 3, whereas 6/8 is a feel based on 2 sets consisting of triplets?

    And 12/8 I've been told is felt as triplet/swing feel as well, so is it typically just a compound of 6/8?

    I've recently written a song where the rhythm goes 1 + 2 + 3 R 4 + R + 2 +

    So the groups themselves are broken down into 5 beats, 2 beats, and 3 beats.

    I wrote it in 12/8, but what would be the difference between that and 6/4, and how would I know which is the technically correct way to write it.
     
  5. For example, this song I've read is in 6/8: (at least the first part -- it gets heavy and a little weird later on). I count it (using the cymbal beats) as 1 2 3 4 5 6, but it also would make sense to me to count it as 1 and ah 2 and ah.

    Of course, as I'm typing this, it's making more sense to me as I count it out in 6 instead of 3... Maybe I just needed to look at things a different way.
     
  6. stringtapper

    stringtapper

    Jun 24, 2009
    Denton, TX
    Pacman's example used two bars of 3/4 (1 2 3 1 2 3) vs. one bar of 6/8 (1 2 3 4 5 6).

    As to the other question, 12/8 is quadruple compound meter; it has four beats with each beat subdivided into three eighth notes. 6/4 is normally a simple meter, six beats per measure with each beat subdivided into two eighth notes.

    6/8 is duple compound, 9/8 triple compound, and 12/8 quadruple compound. The analogous simple meters are 2/4, 3/4 and 4/4.
     
  7. So as 6/8 is sort of 2 sets of 3, 9/8 is 3 sets of 3, and 12/8 is 4?
     
  8. stringtapper

    stringtapper

    Jun 24, 2009
    Denton, TX
    Exactly.

    2/4 = Duple Simple
    3/4 = Triple Simple
    4/4 = Quadruple Simple

    6/8 = Duple Compound
    9/8 = Triple Compound
    12/8 = Quadruple Compound

    Simple = beats divided into two units
    Compound = beats divided into three units
     
  9. So what if I were to make it complicated and do 8th note triplets in 2/4? Since the 8th note triplets make up two 8th notes, that should still come across as 2 quarter notes, albeit counted as "1 and ah 2 and ah". Good so far?

    Would it still be a simple even though it's divided into three units? Or is it still units of 2 because it's 2 triplets?
     
  10. dtiii

    dtiii

    Apr 22, 2009
    nyc
    Say for example that I'm playing a riff in 3/4 at 120 BPM. Couldn't i play that same riff in 3/8 at 60 BPM and have it come out the same?

    When you say ‘come out the same’ I presume that you mean at the same rate or speed. If this is so then I will say no because pulse assignment in accord with rate is a factor that needs to be considered, as well as maintaining the proportion of note values from one signature to the next.

    Working in 3/4, let’s use two measures of quarter-quarter-eighth-eighth as the example rhythm. According to the time signature the quarter note is the pulse unit. Set the metronome at 120bpm and proceed with the conventional counting method:

    1 – 2 – 3& | 1 – 2 – 3& ||

    Now set up the same rhythm in 3/8, keeping in mind that you need to maintain the same rhythmic proportion as the first. The eighth note is the pulse unit in 3/8 time, so eight-eighth-sixteenth-sixteenth would be the newly written rhythm. Now set the metronome to 60bpm. Again using the convention:

    1 – 2 – 3& | 1 – 2 – 3& ||

    Notice that you are moving twice as slow as the first. In order for your hypothesis to be correct you would keep the rate the same for each at 120bpm.

    And 3/4 vs. 6/8...

    While the math adds up the same, 3/4 and 6/8 are not the same. They are two different types of meters; 3/4 is a simple meter and 6/8 is a compound meter. The difference between the two is that a pulse in simple meter divides naturally by two and a pulse in compound meter divides naturally by three.

    Simple meters give all the info right on the surface.

    • top number tells how many beats in the measure
    • bottom number tells which note gets the pulse or beat

    Here are nine simple meters that fall under the ‘more-or-less common’ umbrella:

    2/8, 2/4, 2/2
    3/8, 3/4, 3/2
    4/8, 4/4, 4/2
    Compound meter requires a bit of footwork in order to figure it out.

    • top number divided by 3 equals number of beats per measure
    • bottom number divided by two and add a dot tells which note gets the primary pulse

    It’s actually easier than it seems. Take 6/8 time.

    - 6 divided by 3 is 2, therefore there are two primary pulses per measure (divide by 3 because pulse divides by 3 in a compound meter)

    - 8 divided by 2 is 4. The 4 represents a quarter note value. Now add the dot. The pulse note in 6/8 time is the dotted quarter note.

    On a secondary level we can experience compound meter in a ‘simple’ way. The numbers can be as literal as simple meter:

    6/8

    • 6 beats in the measure
    • Eighth note gets the beat

    While this seems so much easier, it does nothing to communicate the primary characteristic of what a compound meter should feel like in a conventional sense – bigger pulses dividing by 3. (Bridge to Three Blind Mice) Also, when getting into a meter like 9/8 or 12/8, counting out every eighth note as a pulse becomes quite cumbersome… one, two, three, four, five, six, sev, eight, nine, ten, lev, twelve over and over does not sit as well as one-ta-ta, two-ta-ta, three-ta-ta, four-ta-ta.

    Here are nine compound meters that fall under the ‘more-or-less common’ umbrella:

    6/16, 6/8, 6/4
    9/16, 9/8, 9/4
    12/16, 12/8, 12/4

    While this is all convention it doesn’t address every nuance of meter distinction. Bottom line… I think it’s important to have a foundation of the conventions. At the same time, the convention may not serve the immediate need so be prepared for alternative views and other ways to use/express this stuff.
     
  11. dtiii

    dtiii

    Apr 22, 2009
    nyc
    A triplet is a type of tuplet, which is an imposed division. Playing eighth-note triplets in 2/4 time means to play three eighth notes in the span of two, so they would be faster. The simple meter is maintained.
     
  12. dtiii, I read everything you posted, but I've got a weird fever virus thing and can only concentrate in short bursts. I promise I will get back to that, and almost all of it made sense to me :D Thanks for that.

    But now, because my problem is distinguishment, let me ask another annoying question that I'm sure I should know the answer to.

    Say again that I'm playing in 2/4 and playing straight eighth note triplets.

    I would get 1 and ah 2 and ah 1 and ah 2 and ah

    But what's to stop that from being 6/8? 1 2 3 4 5 6 1 2 3 4 5 6.

    Would it depend on the accompaniment? Or would one modulate to the other? My gut instinct tells me that if it was straight triplets, it would be counted in 6, where as if it was standard eights with a triplet section, it would be in 2?

    I'm gonna get this at some point.
     
  13. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    2/4 with a triplet feel would be much the same as 6/8.

    There isn't really any single "correct" time signature for any piece of music - it's just about convention/convenience/ease of writing and reading/et cetera.
     
  14. dtiii

    dtiii

    Apr 22, 2009
    nyc
    Like bassybill is saying, it isn’t about being correct in terms of there being a single option. Granted, there are norms and conventions – a waltz is in 3/4, rock and roll is in 4/4, a march is in 2/2 – but nothing is in stone and there are always exceptions to the norms. In my experience, notating a shuffle blues seems rather arbitrary. It’s typically notated in one of two ways:

    • 4/4 with a direction at the top stating in some way ‘play with shuffle feel.’ This is where the notation of three beamed eighth notes in the span of each beat would correctly be called triplets because the natural division of the quarter-note beat is two eighth notes.

    • 6/8 or 12/8 maybe stating ‘shuffle’ at the top. Here the division of the dotted-quarter pulse, three eighth notes, is not considered a triplet because it is the natural division in this type of meter.

    Which one is correct? If the three-feel within each pulse pervades throughout then I would argue the latter. At the same time, there isn’t anything wrong with the former. I’ve seen it both ways and I will even add that I have probably seen 4/4 as the more common means. (Probably because notating the pulse in this style as quarter notes may be more conventional than dotted-quarters) It really comes down to the individual notating the music. What I wouldn’t consider is 3/8 because it falls too far out of the convention even though it is possible to notate a shuffle using that time signature.
     
  15. That's actually helping me a great deal. It did help answer another question I had about why some groups of 3s are triplets in one time signature and straight notes in others.

    So now that we've got that out of the way... I'm curious about the need for time signatures like 2/2 and 8/8
     
  16. dtiii

    dtiii

    Apr 22, 2009
    nyc
    I will say that when it comes to choosing a time signature it depends upon how the composer wants the pulse perceived in a particular meter - duple, triple, quad, or some other. 2/2 serves a march well because we have two feet – left-right, left-right, 1-2, 1-2, etc… The half-note pulse gives the composer some room with which to work in regard to note division. Arlen’s “Over the Rainbow” is notated in 2/2. It’s a lofty melody for which the broader 1-2 count works better than 4/4 in order to express the affect of the lyric. At the same time, looking at Joplin rags you will see 2/4 as the time to accommodate a two-step dance.

    In regard to 8/8, take note that it didn’t make it into my ‘more or less common’ signatures. I’ve only seen it once. (Not that that means much, it’s just my experience) I walked on a gig and the leader handed me a sheet for “In a Sentimental Mood.” The repeating bass figure played under the head was notated in 8/8. I asked why 8/8 and he responded that it was a one-bar phrase with an eighth-note pulse. It worked fine. I didn't see a need to argue it... especially because he was paying me. :)
     
  17. Russell L

    Russell L

    Mar 5, 2011
    Cayce, SC
    Yes. But there's more to it than that. The feel of 6/8 is two beats per measure, 9/8 feels three (like 3/4, but with every beat having three), and 12/8 feels like 4/4, but with three notes per beat.
     

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