Loudness and musical notation, how music dynamic works

From a scientific point of view, intensity can be measured precisely, but in music notation intensity does not have an absolute value but a relative one. That is why in music we do not speak of sound intensity but of dynamics. So let’s see how we move from the concept of sound intensity, or volume, to that of dynamics. We will also find out how to write dynamics on the staff.

Sound intensity, or volume

Why do we perceive some sounds louder and others softer? How does our ear perceive sounds? In a recent lesson we considered the first quality of sound, pitch. The second quality of sound that we analyze is called intensity instead. This is the correct technical term, however we often also use the synonym volume. So let us go on to analyze the acoustic characteristics of intensity.

Intensity depends on the amplitude of the vibration. For example, if we pluck a guitar string with more force, we will see that the oscillation of the string is larger and the volume of sound, or intensity, is greater. It is therefore easy to see the relationship between the amplitude of the vibration (the movement of the string) and the volume of the sound it produces.

In the lesson on the pitch of sound, we saw how it depends on the number of vibrations per second. In the two images below, the image on the right corresponds to a higher pitch sound than the one on the left, because the number of vibrations per second is greater.

In the next image, we see the difference between two sounds with different intensities. The number of vibrations per second is the same for both images, but the one on the right has a greater amplitude, so it corresponds to a louder sound.

How we measure intensity: the decibel

Just like sound pitch, intensity can also be measured precisely. The unit of intensity is the decibel (dB). The human ear has an audibility threshold of around 5-10 dB, so it cannot perceive sounds with lower intensities. On the other hand, the ear is at risk of damage if exposed to sounds above 100-120 dB, especially over a prolonged period.

The noise of a falling leaf has an intensity of between 10 and 20 dB, the breathing of a sleeping person around 30 dB, the noise from inside a running car is around 90 dB, which is why very high volumes must be used to listen to music in a car.

I don’t know if you’ve ever turned on the car radio with the engine off and been surprised at the very high volume of the music. The volume is indeed very loud if the engine is off, but the day before on the motorway that was the volume needed to be able to hear the music.

Cyclic sounds and noises

However, volume is not everything; our ears and minds are in fact more susceptible to repeated and cyclic noise. This is why many people find the noise of wind turbines unbearable, even if it has a rather limited intensity (around 50 dB).

For the same reason, an alarm clock usually emits repeated sounds at the same distance in time: we are more easily woken up by a repetitive and cyclic sound than by a discontinuous and isolated one, even if it is louder.

Let us now see how intensity is measured in music. In the system of musical notation, we speak of dynamics and not intensity, because music is much more interested in the relationship between different sounds than in the actual intensity or volume.

Scientific and relative measurement: the dynamics

In the scientific field, the intensity of sounds and noises is measured exactly, and the unit of measurement is the decibel (Db). In the language of music, however, the measurement of intensity has completely different methods and purposes. In particular, on the staff, indications of the intensity of sounds always have a relative value.

In music, we are never interested in knowing the actual intensity of a sound or a musical phrase, only its intensity in relation to other notes and phrases. Or even, in relation to other pieces that precede or follow the musical composition. The indications that we find on the staff regarding intensity or volume within a piece of music are called dynamics.

How to write dynamics

Dynamics notation was established between the 17th and 18th centuries. There are three different ways of writing dynamic indications, these three systems are not alternative but often coexist in the same piece, in an attempt to express the composer’s intention as clearly as possible.

Dynamic indications with letters: from ppp to fff

The most common method of indicating the dynamics of a piece or part of a piece is to use two- or three-letter abbreviations with the following meaning:

While the marks at the extremes of this scale are quite clear in themselves, this is not the case for mp (mezzo piano) and mf (mezzo forte). In order to interpret these marks well, we must remember that they are in the middle of the ‘dynamics scale’, so mp is a little louder than p and mf is a little less loud than f.

Especially mp (mezzo piano) lends itself to misunderstandings, sometimes those unfamiliar with the system mistakenly think that mp is quieter than p.

Sometimes the dynamic marks are replaced by the full written indication, e.g. piano or forte. Often this is done at the beginning of the piece, so that the performer can read and dwell on the indication before starting to play. Within the piece it is recommended to use the abbreviated form, which is more concise and quicker to read.

Indications consisting of letters can be reinforced by più (more) or meno (less). For example: più f, meno f

Sometimes composers extend the system by adding other f’s or p’s to the extremes, e.g. ffff or ppppp. The use of these symbols is somewhat unnecessary, because ppp and fff should already represent an absolute superlative: the flattest/strongest possible.

Relative dynamics and subjective dynamics

That of the composer can only be a hope, because as we have already said, dynamic directions are relative, and we can also say that they are subjective. What is loud for me may be flat for someone else. This is not only true for the listener, but it applies to the performer as well.

In fact, each musician has his own basic sound, which he considers neither loud nor soft. For example, on the piano it depends partly on the weight and size of the hand, and to an even greater extent on the temperament of the pianist. I remember my piano teacher telling me to play louder, what sounded like a fortissimo to me was barely a mezzo forte to him.

Regardless of the instrument, every performer has a dynamic zone in which he or she usually plays, if he or she doesn’t make an effort to play quieter or louder. In principle there is nothing wrong with having a personal approach to the music and the instrument we play, but from the composer’s point of view this can be a problem, because the piece risks being completely misinterpreted.

On the other hand, the performer should also be aware of this and try to go beyond his own habits, or he should choose a repertoire that is close to his own personality.

Let us now illustrate two other ways to write dynamic directions.

Crescendo and diminuendo

While some art forms, e.g. painting and sculpture, exist in the same way for a second as for a minute, in music everything is relative and related to the passage of time. This peculiarity of music makes it essential to note on the score not only the intensity per se, but also the transition from one intensity to a lower or higher one.

There are two alternative and complementary ways of doing this. The first is the use of specific terms such as cresc. (crescendo), dim. (diminuendo) or decresc. (decrescendo, more rarely used). Here is the meaning of these Italian words:

• cresc. (crescendo): grow gradually louder
• dim. (diminuendo) and decresc. (decrescendo): gradually softer

These indications may be accompanied by specifications such as:

• molto,very much
• poco, little
• poco a poco, little by little
• subito, immediately

We can thus find a wide range of indications such as cresc. poco a poco, dim. molto, subito cres. and so on.

There are also graphic signs called hairpins, which indicate more precisely where the crescendo or diminuendo begins and ends in a piece of music. Hairpins are not dissimilar to the volume indications often found on electronic devices: hifi, televisions, radios.

Since the system of musical notation is much older than sound reproduction technologies, it is likely that the use of this symbol to indicate volume was derived from musical language.

Final remarks: intensity and dynamics

In this lesson we have seen how in music the approach to intensity is entirely relative and subjective, not subject to the need for precise measurements.

Scientific approach → measurement in absolute values → intensity
Musical language → relative and subjective indications → dynamics

• Linguaggio musicale → indicazioni relative e soggettive → dinamica

We have also presented the three systems used for notating dynamics: letter indications (e.g. f, mp, fff), terms written in full (forte, piano, cresc. dim., poco a poco, subito etc.) and finally, hairpins. As always, if you have any questions or comments about this lesson, please write them in the comments below. Thank you!

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