31

Theory of Fixed Masses

Dynamic Criterion

31.1. CONCEPT OF THE NOTE

We should say straightaway that we do not link the idea of the note with notation. The notes we are talking about and that we will use in our study of the dynamic criterion, the second basic aspect of sounds after mass, are no more notatable than the masses themselves. They are formed sounds with fixed mass, that is, where the matter conforms to the criterion of homogeneity if we omit their dynamic.1 We will come on to variations of mass in a later chapter. In this chapter we will try to hear pure sounds, tonic or thick, vague or channeled, with the same ear, provided that their form is comparable. To concentrate our attention on this, we must avoid having to think about mass; so we will choose fixed masses.

Apart from pitch, what characterizes the note on the score, when it is played, is the duration and nuance specifically indicated on paper, a particular dynamic curve it traces in sound-space, with a beginning, a continuation, and a decay, an elementary morphology we have already described. In a traditional score the dynamic aspect is generally neglected; the idea of a note goes without saying. At the very most we find a few directions for performance: plucked, legato, and so forth, which are hints for the instrumentalist rather than formal elements of composition. But the score also contains a whole system of signs that establishes a network of dynamic directions or discourses between these notes: links including a series of successive notes, crescendo, and so forth. Moreover, there are overall nuances (pp, mf, etc.), where the articulation sometimes requires specific precise dynamics (sforzando, forte-piano, etc.). Generally speaking, all these directions help to situate the appropriate nuance for each note in the context of an overall expressive dynamic; and ultimately, despite rather vague beginnings, every note in a traditional score is a temporal form that is by no means insignificant and that of itself should become part of the rest of the composition by contributing something quite specific to the overall musical effect. We are therefore justified in generalizing the concept of the note by applying it to every dynamic form that can be identified as such.

31.2. METHOD OF APPROACH

The problem of dynamics is relatively simpler than mass for various reasons. The first is that its main dimension is time and that temporal correlations between the physical object and the sound object have an irrefutable medium, magnetic tape, and also a relatively accessible means of describing them: the bathygram. Moreover, magnetic tape gives us opportunities for intervening we did not possess with mass, in particular for highlighting similarities just as much as differences (which we have described under the name of anamorphoses between physical time and perceived duration). For example, we are aware of what is probably not generally known: the localization of perception at the moment of attack, the importance of that attack in the perception of certain timbres, the conditioning of the ear to the density of information, the temporal dissymmetry that results from this, and so on.

To recapitulate the various analyses of duration and sustainment we have already made in chapters 12, 13, and 14 and in typology: in chapter 14 we distinguished three zones of sensitivity to duration in the ear: in the first, very short sounds are heard as impulses (and we saw that it is the “initial conditions” of the development of the sound that are important here, in particular the initial dynamic slope); in the third, conversely, the sound, which is very long, is followed like a sort of sound movement from moment to moment, as the ear tots up the progressive accumulation of information; finally, in the intermediate zone we situated sounds that have an optimal duration for memorization by the ear. In this latter area, unless we have a “coherent and interesting” form, with neither excess nor triteness, the sound will easily be grasped and will leave an imprint on the memory that demonstrates its value and readability, which does not happen in the other two cases.

So the next step would be to account for a general criterion of duration by distinguishing among anamorphosed sounds (where the attack predominates), sounds with a form (or profile), and long sounds with a weak form. Moreover, linked with these general data on the perception of duration, we have seen that typology roughly identified nonexistent factures (continuous or iterative homogeneous sounds), unpredictable factures (accumulations and samples), and, finally, “closed” forms. Our distribution of forms into classes will take all these considerations into account.

Elsewhere, in chapters 12 and 13, we discussed the relationships between instrumental timbre and attacks: in sounds where these are dominant (resonant sounds in particular), it seems they should constitute the basis for a classification of forms. We will see that, generally speaking, they will help us to define the genre of sounds in relation to their dynamic timbre.

Finally, we need to define dynamic species of sounds. For this we will suggest reference points for the intensity and depth of the contours of the profiles.

So far, the plan we are suggesting is similar to the plan we followed in the last chapter for studying masses. Here, however, we will start with the study of the criterion of attack 2 (genres) to take account of the fact that the profile given intentionally to the sound is in many cases itself dependent on the genre of sound available. In particular, for purely physical reasons the profile is often entirely predetermined by the attack itself (in all percussion-resonance sounds).

Moreover, we cannot leave aside double percussions, which occur when the initial onset does not have the same mass as the resonant sound: the vibraphone, the high register of the piano, for example. So here there is duality of mass at the same time as duality of form. Finally, we should note that during their attack even sustained sounds often have a mass that varies rapidly before attaining its equilibrium: the sound does not achieve its “timbre” instantly. Without anticipating the chapter on variations, we will have to discuss those cases where the establishment of certain forms is closely linked to secondary, yet perceptible, effects influencing both the form and the mass of the sound.

31.3. CRITERION OF ATTACK: GENRES OF FORMS

So now we will look more deeply into the criterion of attack, so much linked with the instrumental genre of the sound in traditional music. We will anticipate a classification in seven columns (see fig. 37), which is enough to mark out different attacks without going into too many subtleties. Going from the harshest to the most nonexistent, we will put so-called abrupt attacks (instruments with plectra, woodblocks, for example) in the first column in the classification and in the last column imperceptible attacks (sounds where the intensity is established very gradually).

FIGURE 37. Genres of attacks.

In the middle, in column 4, we will put flat attacks such as the harmonium and, indeed, all homogeneous sounds; these are sounds that have their full intensity from the outset. We should note here, however, that as we saw in book 3, these sounds produce a pseudo-attack in the form of a very short white sound, as the energy suddenly rushes into the ear. As our classification is musical—that is, having to account for the effect and not the physical cause—we will put into the column for so-called flat attacks all the attacks that include slight mordents, whatever their origin: rosin on the bow, tonguing in wind instruments, as well as the pseudo-attack from the scissor cut.

In columns 2 and 6, balancing each other, we will put steep attacks, on the one hand, and progressive or sforzando attacks, on the other. We must not forget that we should not expect perceptions as “symmetrical” as our boxes, or even the printouts from the bathygram. On the one hand, we have sounds whose intensity is established quite quickly, but not instantly, and which are usually sustained sounds; this latter characteristic dominates the character of the attack, which therefore has a secondary role: our attention turns to the overall sound. On the other hand, a steep attack, the prototype of which is the piano, focuses listening on the beginning of the sound: in this case, as we have seen, we have temporal anamorphosis, and here the character of the attack is dominant in comparison with the character of the continuation of the sound.

We still have two columns to fill, on either side of the central column for pseudo-attacks. Between this and the sforzando attack we will put the attack that gives the impression of a musically softened sound, although it appears to establish itself immediately: in practice we obtain sounds like this by being careful about releasing the sound energy. Many sounds are discreetly placed between the mordent of the rosin and the sforzando, between the glottal attack and the rapid but progressive stress, with no clear profile but also with no interference or deliberate mordent. We will call these gentle attacks.

Column 3 is at first sight difficult to fill. We will use it for attacks that can be described as soft. As we will see in the next section, we could think of these as a combination of the first two attacks. A guitar string would normally give rise to a sudden attack like a mandolin, but apart from the fact that it is plucked more gently (fingertip rather than plectrum), the initial impulse is relayed by a strong resonance; the dynamic seems to gain new impetus, and its slope can be weaker than a piano’s, so we will say that a guitar sound has a soft attack and, with it, all those supple pizzicati followed by reinforcements due to the resonance.

This very rough classification does not by any means give an accurate account of all instrumental examples. It will be a waymark. A drum, cymbal, or gong percussion sound, depending on the hardness of the beater and the relative strength of the resonance, will be classified in 3, 2, or 1: a woodblock percussive sound in 1, a guitar pizzicato in 3, and instruments where the impact and the resonance are perceptibly well-balanced in 2: harp, vibraphone, piano, for example. We should further note that repeated percussion sounds with felt beaters progressively stimulating sound bodies (cymbal and drum tremolos, etc.) will be classed with attacks on the right-hand side of our figure (cols. 5, 6, and 7).

31.4. CRITERION OF PROFILE: CLASSES OF FORMS

The above classification puts us in a situation to reach a better understanding of profiles. Depending on the genre of attack, in fact, the dynamic profile is either determined by that attack or else it frees itself from it because of the subsequent sustainment. With percussion-resonance sounds the resonance profile can really only be perceived in itself if we manage somehow or other to free it from what determines it. The second example applies to the majority of sustained sounds: here the attack and the continuation of the sound have relatively independent dynamics.

Besides, we have seen that some dynamic profiles were linked to a more or less weak, but perceptible, variation in mass. Indeed, and we have already discussed this in chapters 12 and 13, this is the case with the majority of percussion-resonance sounds, especially the sound of the piano in the middle and upper registers, where the harmonic content loses various components as the resonance decays. Here, in general, we will use the term linked harmonic and dynamic profiles. Conversely, these profiles may be relatively more independent where the continuation of the sound is shaped by the instrumentalist (or the experimental musician) to be more or less independent of the attack.

Taking all this into account, we will divide forms into two classes: (1) profiles determined by the attack and, in general, linked to a harmonic profile (especially in double attacks); and (2) profiles not determined by the attack and, in general, not linked to a harmonic profile.

1. Profiles determined by the attack

In practice this is the case with percussion-resonance sounds belonging to the attack genres 1, 2, and 3. Experience shows that in this case it is very rare for there to be a development of the harmonic content of the sound during the resonance that is not entirely under the control of the instrumentalist: whether it is striking a bell or a piano keyboard, touching the strings of a mandolin or a harpsichord with a plectrum, a violin pizzicato, or a percussion sound on a drum, there is only one way to go about it: the instrumentalist puts a greater or lesser amount of energy into striking, or stretches the string to a greater or lesser extent with the plectrum. These different sounds form the class of resonant attacks, or anamorphosed dynamics.

(a) The piano: simple attack

We saw in chapter 12 that however preoccupied pianists are with the weight of their forearms or the suppleness of their wrists, in the final analysis it is the strength of their percussion alone that determines the strength of the attack, and hence, on the one hand, the duration of the resonance and, on the other hand, the initial harmonic content and its development. We should not forget that in the bass register of the piano this initial harmonic content remains approximately the same throughout the duration of the note. So can we still refer to linked dynamic profiles and harmonics? Yes, insofar as it is still the strength of the percussion—hence of the attack—that will determine what that constant harmonic content of the note will be. If softer, the attack will give a poorer timbre; if vigorous, the timbre will be brilliant. This is why across the whole register of the piano, pianists, through the strength of their playing, have the power to determine the timbre of every note; even if their action has only one degree of freedom, they identify it in order to attain a level of nuance, dynamic timbre, and harmonic timbre indissolubly linked to every production of a note. It is therefore a complete illusion to believe that with the piano we can keep the same timbre while changing the nuance or vice versa. Conversely, for each note there is an extensive register of nuance-timbre pairs, in every case associated with a particular strength of attack. Finally, we should note that with the piano as with all instruments where it is possible to stop the resonance of the sound at any moment, the musician can have an effect on the decay of the note as well; but here it is the duration (and not the profile) that is no longer entirely determined by the attack.

(b) Most common example: double attack

Compared to what usually happens with percussive sounds, in fact, the piano has the peculiarity of balancing, and hence of not making us hear separately, on the one hand, the impact of the percussion and, on the other, the resonance, at least in the bass and midregisters.

This is precisely because the piano has been set up like this, except that it does not work in the high register, with the resonance becoming comparatively less and less significant. Now, this is what happens with most percussive sounds. When the surfaces in contact are hard, the impact gives an initial sound, a noise that is rapidly muted (sudden decay), the specific color and timbre of which depends on the surfaces in contact, as well as the strength of the blow. Meanwhile, the resonance moves in, and its timbre depends on both the nature of the resonator (piano soundboard, gong, membrane, tensed string, metal sheet) and the strength with which it has been stimulated. The whole impact-resonance gives a double sound, with each of its components having its own law of decay, timbre, and level. There are two harmonic and dynamic profiles.

We find three main examples:

a. The impact is more significant than the resonance profile. This is the case with the woodblock, typical of the sudden, dry attack with two timbres.

b. The attack is sudden, but gives no second timbre and in addition is quickly taken over by the resonance: this is the case with the pizzicato. Although the resonance is not more intense than the attack, it is nevertheless richer and the overall perception includes attack and resonance equally. The pizzicato has these two characteristics, and this is why traditional music adopted it long ago, to the extent that it eliminates the impact, an undesirable perception.

c. The impact is suitably cushioned, and the resonance, for its part, is very strong: this is the case with the mid- and bass registers of the piano, where the impact is practically masked by the resonance.

In vibraphone or high piano sounds the ear can easily distinguish between the impact and the resonance. So these sounds belong physically to type b, with an impact that is not present in the pizzicato. Now, what is of interest to musical perception is mainly, or perhaps exclusively, resonance: psychologically, we pass over the impact in c, since a particular listening intention obliterates it, just as a more objective listening intention restores it.

We can represent these different examples by superimposing two profiles, impact, always sudden, and resonance, disproportionate in the woodblock, but balanced in the pizzicato or the vibraphone, and apparently dominant—that is, drowning out the impact—in the bass register of the piano (see figure 38).

FIGURE 38. Profiles of attack.

2. Profiles not determined by the attack

With the attack types 4, 5, 6, and 7, which imply a steady sustainment, the instrumentalist can dissociate the attack and the continuation of the sound. At a pinch they will be entirely independent of each other.

What happens here to harmonic development in relation to dynamic profile? We can accept that in most cases they are fairly interdependent, although the instrumentalist or singer endeavors to control the sound permanently in order to keep the same timbre through a crescendo or a decrescendo. In electronic music composers have made much use of the opportunity afforded by the electronic studio to create “sound stuff” with completely fixed mass and intensity that can vary from pp to the most deafening ff. We must say, however, that the latter often seems worse than strange or unpleasant; this is because in classical instruments it rarely happens that dynamic and harmonic profiles are so independent of each other; a singer adds timbre to her voice as the swelled note opens out, and the violinist does the same thing; and it is to this close association that the average listener is conditioned. He is therefore startled when he listens to electronic sounds that present the opposite: color becoming brighter while intensity decreases. Here the listener is shocked by what is unusual, not to say “against nature,” in these sounds.

In any case, in sustained sounds the link between the two profiles, harmonic and dynamic, is the result of the habituation of the ear to musical practice, which is itself subject to the laws of sustainment of sound bodies; in sounds in which the profile is not determined by the attack, the instrumentalist remains relatively free to choose and shape both harmonic content and dynamic profile as he wishes. We will place the objects we are dealing with here in the profiles class if their dynamic form has some three-dimensionality and with amorphous sounds if the profile inclines toward the regularity of homogeneous sounds.

31.5. MANIPULATIONS ON FORMS

We prefer to look at this from the standpoint of classical music notes, both because the reader has them in his ear and because it is interesting to apply our analysis to the most classical materials; most of the time these are linked and stereotyped dynamic and harmonic profiles. Thus, using sounds with such random factures as a rubbed string, cushioned or hard impacts, pizzicato, sustainment by breath, and so on, our music has reached this amazing achievement, almost totally erasing the dissimilarity of origins and forms, to the point where durations and nuances seem able to be fixed according to general norms and to be articulated in the notes flexibly enough to create very willed overall forms.

In contemporary music, especially electronic, the composer can work right from the start on the forms of objects; he is free to choose the profiles, dynamic as well as harmonic. Whether we are pro–electronic music or not, we cannot ignore the almost limitless scope that musicians now have to “play” profiles. Musique concrète, for its part, seeks a proper balance between natural and artificial forms.

(a) Manipulations on dynamic profile

The dynamic forms of sounds from traditional instruments can really only result from the more or less rapid extinction of a resonance or skillfully judged crescendos or decrescendos. We cannot recommend going against these forms by using back-to-front sound, contrary to nature. But there is no reason why we should not enrich a resonance artificially or shape a sustainment. In this way percussion loses its rigidity and does not necessarily impose the initial impact, which is not always desirable musically; the flat sound acquires salience. Thus, in addition to its “delta-shaped” classical form (< >), we can obtain a “hollow” form (> <) within the limits acceptable to the ear. Recording, manipulations with the potentiometer, the presence of several microphones judiciously turned on or off, enable us, generally speaking, to realize subtle interplays of form from a sound with a crude form. Enriching the resonance, especially, does not lead to manipulations that are complicated or destroy the texture of the sound: if enough acoustic energy is available, all we need to do is record the beginning at an appropriate level to allow for the required gradual reinforcement before the decay of the resonance.

(b) Manipulations on harmonic content

A natural link due to the nature of sound bodies generally associates a rich, high beginning with an impoverished, darker continuation and decay. This is the case with most sounds with linked profiles. The listener is so accustomed to this link that he no longer perceives the variation in the corresponding mass: it merges into the dynamic development. But in the studio there is nothing to stop us from modifying the usual features appearing at the beginning of a percussion sound and then sharing out the high harmonics to compensate for their disappearance in the unmodified sound. To do this, strategically positioned microphones can record different timbres from the same sound body at the right time and in the right place; filters can also be used, with care.

It should be noted here that by trying to keep the sound’s initial characteristics of mass throughout its whole duration, we are simply imitating the traditional concerns of instrument makers, who always endeavored to obtain a better musical output from the sound bodies available to them. It should also be noted that there is a great divide between the subtle practices we are suggesting and certain crude electroacoustic manipulations that are carried out against all common sense and with no care for the nature of the objects.

The usual link between dynamic and harmonic profile can be broken, as we have seen, but we could go further. The two families of forms come from percussive and sustained sounds. Could we overcome this natural division and produce, for example, a sound with the form of a piano note but the mass and timbre characteristics of a violin, or vice versa? Manipulations such as these are now possible thanks to the form modulator described in appendix B in chapter 23. Apart from its interesting technical performance, it offers a useful tool for both applied and basic research.

(d) Mixing, editing, and so forth

Less ambivalent in their principle, although perhaps more surprising to the ear, are mixing and editing using elements of recorded sound, enabling us to fashion original sounds by a more or less free association of different timbres and profiles. This is one of the most obvious opportunities for experimental music, but, as we can see, it often tries composers’ patience. A technique such as this requires the same care as animation image by image, which is saying a lot. Less-patient musicians expect that electronics will soon give them a synthesizing or analyzing machine, or else they prefer to go back to the orchestra, entrusting it with the effects they have acquired in the studio. But the studio, in our opinion, is still far from having given up all its secrets.

31.6. THE DYNAMIC FIELD

We suggest that the reader consider what we call dynamic field as the counterpart in the perception of forms of the pitch field in the perception of masses. Fletcher was first to explore this field with pure frequencies in a steady state. For sounds with unremarkable mass and profile this dynamic field is almost unknown. Perceptions are only partially additive, even where there is permanence and with tonic masses, which is particularly apparent in the fact that sounds mask each other. As soon as a mass is profiled in time, however, the question of its overall intensity is raised, as well as its intensity in relation to the accidents of its profile. There are so many problems that need their researchers, researchers aware that there is probably no form of synthesis that would allow us to move from simplified examples to the level of the supposedly general, because every particular mass or profile structure gives rise to new perceptions. So we can only suggest an outline for study that will serve as an aid to memory and at the same time discourage any rash generalization of Fletcher’s curves.

(a) Mass profile

We could already have discussed this in the context of the position of mass in the pitch field. The mass profile is made up of all the (perceived) intensities of the various components of the spectrum of a sound. It is a more or less overall or detailed perception of the components and consequently can only be very roughly deduced from the acoustic spectrum or Fletcher’s curves. Wegel and Lane (1924), in fact, show that “prolonged sounds of sufficient intensity mask high notes over more than an octave above them, although they do not mask lower sounds at all.”3 The presence “of an intense pure sound of long duration,” says Winckel, “with a frequency of 800 Hz (around G 5) raises the pitch of the neighboring notes by almost 7%, i.e. a semitone, across a fifth. The difference is still 6% for a 500 Hz sound (close to B 4).”⁴ We should not forget, however, as Fletcher’s curves show, that at equal level (decibels), sounds with different frequencies can have very different levels of loudness. The perception of the dynamic mass profile must therefore be the subject of specific experimentation with its waymarks within perception itself, intended to draw out characteristics of the genre of the sound, which are unpredictable from an a priori starting point.

(b) Weight of a mass

The idea of weight can be deduced from the above reflections if we notice that we cannot talk about the intensity of a mass, where there is no steady state, without referring to the context: we use the term weight for the intensity of a given sound in relation to one or several other sounds. We can find all sorts of comparisons here: comparisons that can be made between sounds belonging to the register of a single instrument, when we evaluate the respective weights of its notes, and in relation to a yardstick sound used as a reference for all possible sounds; so, then, we are in experimental conditions leading to a generalization of Fletcher’s curves. Such comparisons, apart from their difficulty, are of practically no use in music, inasmuch as in traditional music we are always in the contexts of particular instruments, and in experimental music we ought only to compare dynamic structures formed of objects of the same genre.

It seems that the majority of nuances occur less in the loudness than the softness of sound. The subjective calibration of sonorities in terms of decibels, 5 for C, shows that half the nuances (from ppp to mf) have been covered as soon as the physical level (decibels) of the sound changes by a quarter of its value. More precisely, we could say that on either side of mezzo-forte two “laws” of nuance in relation to decibel level come together: one, linear, going toward strong nuances, and the other, more rapid, toward weak nuances. These findings will come as no surprise to musicians who know the subtlety and effectiveness of pianissimi in music, which is tantamount to saying that the ear is in the best conditions of receptivity and attentiveness with soft sounds. In any case it is important to remember that the scale of nuances remains, above all, a specifically musical mode of perception, the criteria for which depend on the context and particularize the overall indications of physical measurements but without going against their general meaning.

31.7. DYNAMIC SOUND SPECIES

We will continue waymarking these terrae incognitae, first of all discussing the balance between perceptions of mass and timbre:

(a) The salience of harmonic timbre

Here we must proceed with extreme caution. We have already tentatively sketched out a little four-box diagram contrasting the pairs dark-light (site) and narrowness-amplitude (extent) for a salient sound in the pitch field. The boundary between timbre and mass is vague, since we attribute to timbre in our sense what we do not know how to identify in the mass. A real analysis of mass profile would take everything into account, including harmonic timbre, but would ignore that musical custom of more or less separating the two perceptions. We will therefore, with a few question marks, place the property of richness in column 6 of the general diagram (section 34.3) as the counterpart of mass profile. As for the secondary qualities of the perception of pure sounds (density-volume), if we want to distinguish them from mass, we will have to compare them with the narrowness-amplitude pair of a subjective timbre.

(b) Weight of a mass in relation to its duration

The relative intensity (weight) of a permanent sound depends on its duration and its profile. At the two extremes, either the ear will not have analyzed how the energy appears and disappears (short sounds), or else it will have become tired (long sounds). Furthermore, loud sounds oblige the ear to adapt, or tire it, which is shown by an apparent reduction in intensity that also affects the subsequent sounds for some time. Von Bekesy has shown that a sound that followed a loud, prolonged sound at the same pitch was heard as less loud (by about 5 sones) after an interval of a second and a half. Independently of these phenomena, there is no doubt that dynamic profile introduces a perception of nuances different from the perception in a steady state. The intensity of a piano note or a pizzicato is evaluated differently from a held breath or bow sound. There is an anamorphosis in the perception of intensities, as in temporal localization.

So in addition to the perception of weight, we must consider the fact that this perception is more or less anamorphosed or localized at a particular moment in duration—that is, the impact of sounds, corresponding less with their intensity than the nature and speed of their variations. We will give three examples of these effects, which we will group together under the name impact. The first is commonplace: in a high-intensity sound context, what we perceive best, provided the ear is not physiologically saturated, is what varies fast enough to bring about precisely what we call impact. For example, the meowing of a cat, with a weak level, will nevertheless stand out in a hubbub. So it is a question of the three-dimensionality of the variation in relation to duration. Second example: the acousmatic listener’s surprise when he hears unexpected noises on the record, untimely coughing that he had not heard in live listening. We have already given a partial explanation of this fact when we said that he ignored this information when he was in the concert hall. But what interests us here is that these noises are all the more inopportune when they are made up of rapid forms. Third example: concert halls that become silent before the opening bars of a concert demonstrate the same phenomenon: the slightest creak of a chair, a string breaking, a dropped drumstick are disproportionately sensational sounds because of the tenseness of the silence: the reference level then is exceptionally low. So what we call impact gathers together everything that weight had omitted.

Finally, these psychological aspects are not the only consideration. Whereas we expected that prolonged sounds, which as we have seen tire the ear, would diminish its sensitivity, we notice that, while its overall sensitivity is indeed affected (the intensity of sounds seem to decrease), its differential sensitivity increases: von Bekesy’s work has shown that after listening to a prolonged sound, we perceive subtle variations in intensity (and also pitch) better. Is the ear better adapted, or more receptive, to a new “piece of information”? It does not really matter; the fact is there, and this differential sensitivity increases with duration to attain a permanent maximum after one minute. Impact is therefore not only linked to the density of a variation in profile but also to tiny breaks in unvarying sounds. So no dynamic can be calculated rationally either through the laws of physics or the writing on a score. While the interplay of pitches conforms reasonably well to our predictions, the same is not true of the plastic forms of the structures of objects produced by each individual act of assembly and molded in different ways by each individual act of listening.