When we listen to music or songs, even if we are not aware of it, many things are happening at the same time. One of the most important aspects is the rhythm, that kind of musical heartbeat, what moves our feet and shakes our bodies. And to organize or try to explain this phenomenon of nature, musical theory defined the concept of compass.

The rhythm and the beats

To begin with, perhaps it will be useful to talk briefly about musical rhythm.

Our personal relationship with time, with the duration of things and with our perception of all this is quite complex, but when it comes to music it seems that everything is simpler.

There is something innate in this whole affair. Perhaps because in the womb of our mothers we already hear the regular beat of her heart, or because of the recurring swaying of her steps.

The fact is that we are born with the ability to recognize those patterns, those recurring pulses that are the basis of rhythm, in general, and of the rhythmic combinations in music.

And, within the enormous variety of rhythms that we can hear around the world, a pulsation can be identified in all of them, something implicit, more or less evident, that sustains any rhythmic combination.

And that pulse, moreover, usually meets with others in repetitive blocks as well, in which some are perceived as stronger than others. We call those prominent or stronger pulses accents.

This set of ideas and their possible combinations give rise to what we know as musical metrics and one of its most important elements are the bars.

What is a musical compass?

So, a musical compass is a group of accentuated pulses in a certain way that are repeated in time.

Otherwise, based on a reference musical figure, a specific number of these figures will complete the measure, with the first one accented if there are no other indications.

Representation of the compasses

When writing a score or communicating with other musicians, we will use a certain terminology to talk about this matter.

When we see a compass indication, what we will find will be things like 4/4, 3/4, 4, 6/8, 12/8, etc…

If we look closely, although the numbers change, the structure of what is represented does not. We always find a number above or in front and another number below or behind

Fine. And what do these numbers mean?

We call the first or higher number the numerator and it determines how many musical figures appear in each measure of that type.

And the second number, or the lower one, is called the denominator and tells us what base musical figure we are talking about.

  • A 1 = round (four beats)
  • A 2 = white (two times)
  • A 4 = quarter note (one beat)
  • An 8 = eighth note (half beat)
  • A 12 = a semicolon (a cuarto de tiempo)

For example, what we know as 4/4 time signature means that each measure will consist of four black notes or four beats. The first 4 of the formula or representation, the numerator, indicates that this measure consists of four figures, and the second 4, the denominator, indicates that these four figures of that measure are black, also known as a beat.

simple and compound compasses

The first classification that we must take into account about the bars is that each beat or beat of the bars can also be perceived, in turn, with smaller beats or subdivisions.


A simple compass would be one whose reference figures can be subdivided into halves. For example, a 2/4 or a 3/4.

And a compound compass is one whose base figures are subdivided into thirds. For example, a 6/8 or a 9/8.

Types of time signatures

This may sound a bit confusing. We are going to explain it better and we will see a few types of compasses.

Binary compasses

  • 2/4 indicates a two – beat time signature that can be divided into halves during performance.
  • The 6/8 indicates a type of measure of six eighth notes that can be subdivided into two groups of three each. A binary compass with ternary subdivisions.

Ternary time signatures

3/4 time signature
  • 3/4 indicates a measure of three beats that can be divided into halves each of them. That is, a ternary compass with binary subdivisions.
  • The 9/8 indicates a measure of nine eighth notes that can be subdivided into three parts each of those three times. This would be a ternary compass with also ternary subdivisions.

Quaternary time signatures

4/4 time signature
  • The 4/4 will indicate, then, a measure of four beats that can be subdivided into halves each one of them. If we continue with the academic terminology, a quaternary time signature with binary subdivisions.
  • The 12/8 , for its part, indicates a type of measure that lasts twelve eighth notes, that is, four beats, which can be subdivided into three parts each.

We can check the many combinations that we have to compose music and, in reality, we have only mentioned some of the options, the most basic and recognizable.

If we add different accents than the ones that the western ear is used to or mix different measures in more complex sequences, we will still have more possibilities at our disposal.

Amalgam time signatures and other types of irregular time signatures, although they are probably not the most used in the music we hear on a daily basis, appear here and there regularly, often as an essential feature of some musical styles.

Flamenco styles, progressive music or many rhythms of African origin use keys and resources that, from the base, are supported by different recurring pulsations and accents, resulting in musical pieces and songs with characteristic rhythmic sensations.


As you can see, being aware of the fundamentals of musical rhythm is very useful to reach a more complete and profound understanding of this very special and powerful phenomenon that invades us and invites us to dance, to move, to express ourselves better, even.

This way of understanding and representing the metrics of songs and music often requires annotations or additional indications to better understand how a piece should be accented and interpreted. Thus, for example, saying or reading the word ” swing “, in a 4/4 time signature, will mean that the accented times are no longer the first and third of each measure, but rather the second and fourth. A large part of the music with African roots feels and uses this type of accentuation as something habitual.

This article is just a summary, an introduction to the fantastic world of time signatures and rhythm from a music theory point of view.

In summary, if you like music but are also interested in or even compose songs or instrumental music, knowing and understanding the variety of musical time signatures will give you a richer vision of the works you listen to and, probably, an added way to enjoy this miracle that we know as rhythm, as songs and as music.