# Tchaikovsky's sleeping beauty Op. 66 introduction measure 28

I was listening to the ballet sleeping beauty. In the beginning in the introduction, when there is a change of time signature. (measure 28) it felt like three beats. I looked up the score, and it changes to 6/8 I was wondering why it isn't 3/4?

Edit, I'm not ask the difference between 3/4 and 6/8, what I'm asking is an explanation in this piece when the tempo is slow what made the composer write in 6/8. Listening to the piece without looking at the score what pulses do you feel? I'm asking this because I transcribe old Cappella melodies by ear and have this dilemma when such I get to such a piece, it feels three pulses, is it 3/4 or 6/8?

• A look at the relevant score would help here!
– Tim
Commented Jul 30, 2023 at 12:27
• Why a composer wrote something one way and not another way is almost almost pure speculation. Commented Jul 30, 2023 at 14:00
• My question is more then why, the question is more for me to understand the difference between 3/4 and 6/8. With this piece all what I know is off, my perception of these time signatures needs to be relearned. Commented Jul 30, 2023 at 14:16
• That's explained here: music.stackexchange.com/questions/120343/… Commented Jul 30, 2023 at 14:23
• Does this answer your question? Does 3/4 time signature differ from 6/8? Commented Jul 30, 2023 at 17:17

Tchaikovsky wants phrasing in terms of groups of six rather than two groups of three.

Tchaikovsky certainly could have notated the passage in pairs of 3/4 measures (replacing the eighth notes with quarter notes, sixteenth notes with eighth notes, etc.) or even two measures of 3/8. Those would be essentially the same, differing only by the note-types used. (I leave aside discussion of implied/interpretive differences between 3/4 and 3/8.)

However, by notating in 6/8 (i.e., two measures of three combined into a single measure of 6), Tchaikovsky is saying that the second "measure" of three (beats 4, 5, and 6) is subordinate to the first. That is, beat four is weaker than beat one. Were the passage notated in three, it would imply that each beat one (i.e., beats 1 and 4) is of equal musical value.

A recording that sounds like 3/4, that well may be the choice of the conductor or just how the recording strikes the ear of the individual listener — someone else might hear the same recording in six.

The answers posted in comments explain the difference between 3/4 and 6/8, which is basically 3 beats (quarters) per bar versus 2 beats (dotted quarters) per bar.

The giveaway here is not until bar 30 where the woodwind melody is very obviously grouped into 3’s. Perhaps you are hearing the eighth notes as the beat and that is why it sounds like 3/4 to you.

• Isn't 3/4 also grouped in three? Normally what I know is 2 x 3 beats is a 6/8 time signature. Here I feel 3 pulses separate. Commented Jul 30, 2023 at 19:37
• @Nachmen Of course, 3/4 is groups of 3. This is a slow tempo so you are probably feeling the individual eighth note pulses as beats like I mentioned in my answer. The eighth notes are grouped in 3’s and there are two groups per bar. That means every group of 3 eighth notes is one beat and there are 2 beats per bar. Commented Jul 30, 2023 at 22:24
• This is what I want to understand why, is it a whim or is it music theory? I want to learn, this info is what I want to know. Because I transcribe old stuff by ear and I am never sure when the melody is in a slower tempo do I write it as 3/4, or 6/8? Commented Jul 31, 2023 at 6:09
• @Nachem In this and many cases it is the discretion of the composer, arranger or orchestrator. If you compose something it is your choice whether to write it in 3/4 or 6/8. If you are transcribing something it is up to you to make a choice as to how to write it. If published music exists for the piece you transcribe it may be different than what you chose. Commented Jul 31, 2023 at 6:29
• @Nachmen If you consider it, the short answer to your question of why 6/8 and not 3/4 is: Because that is what Tchaikovsky decided to use when he wrote it. Commented Jul 31, 2023 at 6:31

To add to other answers, the time signature influences how musicians will play the music — the subtle variations in timing and stress.  So the general answer to why Tchaikovsky chose 6/8 is simply: he thought it would give the effect he wanted.

(I once wrote a piece which simply didn't feel right — I later changed the time signature, and next time they performed it with exactly the feel I wanted.)

As to why 6/8 gives a different effect from 3/4 in this case, I think that's covered by other answers.  Both 3/4 and 6/8 have a triple time, but in 3/4 that's the primary beat, while in 6/8 it's a subdivision of an overarching duple beat.  How strongly you hear that duple beat is probably subjective, but without it the music would probably sound different.