2/4 Cut Time

There is certainly also a historical path behind it and they are not exactly the same

WAM wrote:

There is certainly also a historical path behind it and they are not exactly the same

I believe so too, and one probably needs to go to ancient music to know its origins. And, since I am not an expert in ancient music, I leave this part to those who know more than me. However, there are two things I am sure of: reading a fast tempo in "cut time" can be easier because it avoids the use of very small values and, secondly, from a purely rhythmic point of view, between 2/4, 2/2, 2/8, 2/16, 2/whatever-you-want ... there is no difference (just as there is no difference between 3/8, 3/4, 3/2 etc etc etc...).

Cut time historically precedes 2/4, simply because the most used unit of time in ancient (and Baroque) music is the minim, a direct consequence of so-called white notation, which is the most widespread notation of mensural music. The cut time signature, or the slashed C, actually derives from medieval time signatures of mensural notation, albeit in a "wrong" way. The durations within the measures were decided according to "Tempus" and "Prolationes", which are more or less today's beats and subdivisions. The tempus perfectus had 3 beats, the tempus imperfectus 2. The prolatio maior had 3 subdivisions, the prolatio minor 2. Perfect time with major prolation had three beats each subdivided by three, "similar" to 9/8. But here is where the mistake lies: every beat of 9/8 lasts a dotted quarter note; every beat of perfect time with major prolation lasts a "semibrevis". Prolation indicates how to subdivide the semibrevis, but it does not change its overall duration. Therefore, rather than 9/8, perfect time with major prolation corresponds to a 3/4 with a mandatory subdivision into triplets. Furthermore, the semibrevis compared to today's note values was longer... that is, figures with very short durations are "typical" of modern music. I am not talking about actual chronometric durations—a 2/2 can be accelerated as much as one wants—but I am talking from an exquisitely graphic, semiographic point of view. From this point of view, which can only be historical, obviously, a tradition of transcribing ancient and Baroque scores arises in which the semibrevis is transcribed as a minim :-) and therefore, a perfect time with major prolation (circle with a dot in the middle) becomes 9/4, a perfect time with minor prolation (circle without a dot) becomes 3/2, an imperfect time with major prolation (a C with a dot) becomes 6/4 and, finally, an imperfect time with minor prolation (a C without a dot) becomes 2/2.

Dell me if I haven't been clear.

I got lost on the prolation

Paulo wrote:

I got lost on prolation

Tempus = meter; prolation = subdivision;

Perfect time = in 3; imperfect time = in 2

Major prolation = ternary subdivision; minor prolation = binary subdivision.

So, for example, Perfect time with minor prolation is what we call "ternary movement with binary subdivision" (3/4, to be clear); imperfect time with major prolation is "binary movement with ternary subdivision" (e.g., 6/8); perfect time with major prolation is "ternary movement with ternary subdivision," such as 9/8.