How does one choose the correct time signature to match the tempo and vice versa?

Question

I am having quite some difficulty trying to determine the correct time signature as well as the tempo to match the rythm of the song I am trying to write for. It's not so much that I don't have an understanding of these concepts in theory, but in practice I can't get a grasp of it.

I have what I think may be a 3/4 time signature, though I do know for certain it's three beats of some note duration, it definitely has a ONE two three - ONE two three type of rhythm.

Though, I can't decide whether each beat is a 4th note at a faster tempo, or an 8th beat at a slower one.

For instance, these two 'beats' are identical, apart from the BPM and time sig, but the feel of it, and the paste of it are the same.

Here, the BPM is set to 210, but the note length span across for 1/3 of a bar.

Here, the BPM is reduced by 1/3 of it's initial value, 210 to 70, but the note length are also 1/3 of what they were, taking up 1/3 of, erm, a section of a bar?

When using a metronome, the bottom one sounds like the right tempo. However, my mentality is that without the metronome, then the bpm is the same anyway, not officially but within the song. But what I like about the bottom image is that it seems that the song itself would be easier to handle, since more content spans less distance, thus it seems I could get a better idea on what happens where in the song, since I can just 'see everything', or at least a lot more.

At the same time however, this is my first song, so am not really inclined to trust my own opinion just yet. So, am wondering if at first, if it even matters if I play a 210 bpm with longer notes, or 70 bpm but with the note lengths cut by 2/3's. Or, if this is of importance, how come, and what can I do to hone my skills in this particular area within music?

Answer 1

Tempo and Time Signatures really don't have anything to do with each other. A time signature is how you group, count, and accent beats and tempo is how fast the beat is. Changing the tempo as you are doing does not affect the time signature at all.

3/4 or 3/8 or even 3/2 will group the beats in the ONE-two-three pattern you want and as a composer the tempo is a big, independant element you need to think about. There's no right or wrong answer. Your piece will feel different at different tempo and I suggest you play with your options to find out what you think is best and listen to songs in 3/4 to get a feel for how they sound and how the tempo they are at affects them.

Another time signature you may want to try is 6/8 which is felt as ONE-two-three-FOUR-five-six where beat 1 and 4 are accented, but 1 is perceived as stronger. 6/8 a similar, but slightly different feel to it then 3/4 and it's another thing you can consider and again listen to different examples to hear how they work.

At the end of the day it is your piece of music and you have to like it.

Answer 2

Dom is absolutely correct on the musical end.

My question is more concerned upon technique and common/good practice, thanks though! :)

From a best practices standpoint, I would say the 70bpm setting is the correct one.

If you are just composing in the software, nothing else, it wouldn't matter. If you want to start syncing to drum machine plugins, video, external time based FX, etc.you want to use an "expected" value for the BPM. This will also makes it a bit easier to collaborate with others.

The default BPM on virtually every software package is 120bpm in 4/4 time. Which is really kind of fast for many songs. In 3/4 time you would need to set it at 80bpm to get the down beats (the one) flying by at the same absolute time interval (i.e measured in milliseconds), because there are less beats to the bar.

So for a moderate tempo song, 70 sounds exactly right and will make it easier to set things like delay plug ins that allow you to use time signatures to set the repeats.

Answer 3

Music is structured sound - while it usually has meter, there's no need for music to have time signature or tempo markings to exist. Time signature is just a tool to help everyone involved in the music making process. The best practice is to choose the one that most simplifies your music thoughts.

For example:

The composer chooses the time signature to bring out key parts of the measure. 6/8 is played with every other beat accented, and it's really a "fancy" type of a 2-based meter. 3/4 is played with every third beat accented. 9/8 is a fancy version of 3/4. 3+3+2/8 is a "lumpy" version of 4/4, but will dramatically affect the way the piece is played. Writing 3+3+2 tells performers "You can expect this structure throughout," so in some cases it's the right answer because it's the least complex choice. A piece written in 3/8 but full of dotted eighths might sound identical to a piece in 2/4. Write it in 2/4 if it's less complicated. Or switch back and forth.

Beyond that, you can write the same piece in 3/8, 3/4, or 3/16. It's really up to the composer, but dictated by the level of subdivision going on. If you're in 3/4 and find yourself writing lots of 64th notes, switch to 3/2 or 3/1 to simplify the notation. Conversely, if you're writing lots of dotted whole notes in 3/2, consider 3/4 or 3/8. In modern music, the quarter note and eighth note are the most comfortable so try to make your music revolve around them as much as possible.

To demonstrate that there's nothing intrinsically linking the meter and tempo, consider that our longest usual note, the double whole note, is called the breve ("short") because it was the shortest note in early western music. There has been intense rhythmic inflation going on for the last several hundred years, with tempos decreasing to compensate for increasing subdivision of beats.

If you're writing electronic music that no one will ever have to see a score for, then you don't need to worry about it. But the best practice is to use the tempo and the time signature to convey your thoughts as simply and accurately as possible.