Room acoustics and psychophysics

7/29/2019 Room acoustics and psychophysics

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by Dr. LUCHIAN IONESCUby Dr. LUCHIAN IONESCUby Dr. LUCHIAN IONESCUby Dr. LUCHIAN IONESCULect. univ.Lect. univ.Lect. univ.Lect. univ. FACULTATEA DE ARTEFACULTATEA DE ARTEFACULTATEA DE ARTEFACULTATEA DE ARTE


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Nowadays information is sent in such a way, as to be

easily understood. Perceivable it is due to her twofundamental states of being - sensory and potential.According to the laws of physics, the particles that leavethe transmitter towards the receptor containinformation and have energetic power of charge,conservation, transport, conversion (translation) ofdata. The nonlocal transmission of music does not take

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in account neither the cultural level of the personsengaged in communication, nor their level ofprofessional mastery, nor the psychic state of mind ofthe partners on the day of the interpretative action, but

only the level of musical interpretation, technically,esthetically, formally as level of personal contribution,the quality of the instruments.

L. Ionescu, Room acoustics and psychophysics 2013www.dynamic-psychology.eu


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Producing musical sounds and listeningto them is almost always done in rooms

or halls-technically speaking- in enclosedspaces. These enclosed spaces havebounding surfaces (walls, floor, ceiling)that reflect the incident sound. Becauseof these reflections the emitted Sounddots not only reach the cars of thelistener via the straight line from sourceto listener, but also via numerous other

by Cait O'Connor

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.

listener without any reflection is calledthe direct sound; the sound that arrivesafter one or more reflections is called theindirect sound or reverberation. The

presence of an indirect sound field has aprofound influence on the sound imagethat the listener receive. The subjectiveeffects of the indirect sound field makeup what is called the acoustics of a roomor hall.



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by Mary Ruth Walsh



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Psychophysics is commonly defined as the quantitative branch ofthe study of perception, examining the relations between observed

stimuli and responses and the reasons for those relations. This is,however, a very narrow view of the influence it has had on much ofpsychology. Since its inception, psychophysics has been based onthe assumption that the human perceptual system is a measuring

instrument yielding results (experiences, judgments, responses)that may be systematically analyzed. Because of its long history(over 140 years), its experimental methods, data analyses, andmodels of underlying perceptual and cognitive processes have

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reac e a g eve o re nement. or t s reason, manytechniques originally developed in psychophysics have been usedto unravel problems in learning, memory, attitude measurement,and social psychology. In addition, scaling and measurement theoryhave adapted these methods and models to analyze decision

making in contexts entirely divorced from perception.


by Gerard Byrne


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Psychophysics also refers to a general class of methods that can be

applied to study a perceptual system. Modern applications tend torely heavily on ideal observer analysis and signal detection theory.Psychophysics has important practical applications. For example, inthe study of digital signal processing psychophysics has informedthe development of models and methods of loss compression.These models explain why humans perceive very little loss of signalquality when audio and video signals are formatted using losscompression. Many of the classical techniques and theory of

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Fechner published Elemente der Psychophysik. He coined theterm "psychophysics", describing research that he thought relatedphysical stimuli to the contents of consciousness such assensations.

Where as the physical aspects of sound in an enclosed space havebeen studied for almost a century, the subjective effects cannotclaim a long history of research. Research in subjective roomacoustics begins after World War II, and its results up to now aremainly tentative.



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by Mark Francis



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We will first briefly examine the physical aspects of indirect sound.The differences between a situation with and one without indirectsound may be summarized in three points:

1. The indirect sound adds sound energyat the position of the

listener, resulting in a higher intensity than there would be withoutindirect sound. The gain can be substantial and depends, of course,on the sound absorption (and reflection) of the boundaries. It canbe up to 10 or 15 dB.

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.its path is always longer. If the indirect sound includes some strongsingle late reflections with delays of more than 50 m/sec, these arecalled echoes.

Usually, it is possible to distinguish some discretely traceable

reflections from the walls and ceiling that arrive first after the directsound and a mass of diffuse later reflections coming from alldirections.


by Tim Tate


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The subjective effects of a room on the perceived sound can beseparated in theoretical description. However, in practicalsituations and even under laboratory conditions, they can never beseparated because they are all dependent on one physical source,

the indirect sound.The subjective aspects of the spatial effects of indirect sound are

indicated here by the term spaciousness. In the literature noprevailing term has come up yet. One finds terms such as

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"liveness", "richness", "ambience", "fullness of tone", "spatialresponsiveness", "spatial impression", "resonance", and"reverberance". In the German literature the list of terms isrestricted to Raumeindruck, Rumlichkeit and Halligkeit (roomimpression, spaciousness, and reverberance). The German authorstreat Raumeindruck as a generic term, with Rumlichkeit andHalligkeitas special aspects.



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by Alfredo lvarez Plgaro



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The subjective aspects of spaciousness have been described byMaxfield and Albersheim (1947) as follows:(1) a change in the general tone quality, stated by musicians to be

improved "resonance" or "roundness;"(2) the blending of the sound from the various instruments of anorchestra into a single coordinated sound;(3) the sense of acoustic perspective;

by Tom Climent

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(4) the realization on the part of the listener of the approximatesize of the auditorium., Beranek mentions the following aspects ofa "live room": more uniform loudness, enhancement of bass andtreble, fullness of tone, range of crescendo, sound diffusion,intimacy and texture. In this list level and temporal effects are also

included.



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The right amount of definition andspaciousness are decisive for good subjective

room acoustics. However, function isnegatively correlated with indirect sound whilespaciousness is positively correlated. So, it willnot come as a surprise that definition andspaciousness have a high negative

interrelation. This means that in practice acompromise between requirements fordefinition and spaciousness is alwaysnecessar .

by Bea McMahon

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However, comparing the formulas for clarity(objective definition) and objectivespaciousness, one will notice that onecomponent of the sound field affects bothdefinition and spaciousness positively. It is thesound coming from the sides and from therear later than 40 m/sec and earlier than 80m/sec after the direct sound. It may beconcluded that these reflections are of great

importance for good acoustics of a room orhall. L. Ionescu, Room acoustics and psychophysics 2013www.dynamic-psychology.eu


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Subjective musical room acoustics is arelatively new field of scientific

enquiry. It does not posses time-honoured concepts, methods, or basicresults. It is not yet a standardcomponent of handbooks, textbooks,university curricula, or scientific

institutions. Its nature is to a largeextent interdisciplinary. Methods andconcepts have been derived fromh sical acoustics as well as from

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psychology and from musicology.However, the rapid growth of theliterature concerning its problem areasduring the last decade shows that it

will soon become an indispensablepart of both room acoustics andpsychophysics.


by Isabel Nolan


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Out of the recent literature an important subjective features ofroom acoustics have emerged: spaciousness. A number ofdefinitions and measurement procedures for both the subjectiveattributes and its objective counterparts have been proposed,which include a wide range of ways of thinking. Much research willstill be needed before the interrelation between the two basicconcepts as well as their connection with physical-acoustical

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. ,

methods available that promise good progress, such as simulationtechniques for room acoustics and the modulation-transferfunction. These methods have a mainly physical background. Theyshould be applied along with methods such as factor analysis and

multidimensional scaling, which have a predominantlypsychological origin. The recognition of the hybrid nature ofsubjective musical room acoustics is essential for the solving of itsquestions and problems.



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by Carla Guagliardi



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REFERENCES

Beranek, L. L. Acoustics. New York: McGraw-Hill, 1954.Edwards, R. M. A subjective assessment of concert hall acoustics.Acoustica, 1974, 39, 183-195.Gescheider G (1997). Psychophysics: the fundamentals(3rd ed.).Lawrence Erlbaum Associates.Hawkes, R. J., & Douglas, I1. Subjective acoustic experience inconcert auditoria. Acustica, 1971, 24, 135-150.Houtgast, T., & Steenken, H.J.M. The modulation transfer function

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. ,

1973, 28, 66-73.Kuhl, W. ber Versuche zur Ermittlung der gnstigsten Nachhallzcitgrosser Musikstudios. Acustica, 1954, 4, 618-634.Kuhl, W. Rumlichkeit als Koelemente des Raumeindrucks.

Acustica, 1978, 40, 167-181.Lochner, J. P., & De Villiers Keet, W. Stereophonic andquasi-stereophonic reproduction.Journal of the Acoustical Societyof America, 1960, 32, 393-401.



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Macfadyen, K. A. A method of assessing musical definition in an

auditorium. Applied Acoustics, 1970, 3, 181-190.Maxfield, J. P., & Albersheim, W. J. An acoustic constant of enclosedspaces with their apparent livencss.Journal of the AcousticalSociety of America, 1947, 19, 71-79.

Meyer, J. Acoustics and performance of music. Frankfurt am Main:Das Musikinstrument, 1978.Reichardt, W. Vergleich der objectiven raumakustischen Kriterienfr Musik. Hochfrequenztechnik and Elektroakustik, 1970, 79, 121-

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128.Reichardt, W., Abdel Alim, U., & Schmidt, W. Definition andMessgrundlage eines objektiven Masses zur Ermittlung der Grenzezwischen brauchbarer and unbrauchbarer Durchsichtigkeit beiMusikdarbictung. Acustica, 1975, 32.

Reichardt, W., & Lehmann, U. Sind Raumeindruck andDurchsichtigkeit des Hrerlebnisses im Konzertsaal Gegenstze?Applied Acoustics, 1976, 9.



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Reichardt, W., & Lehmann, U. Raumeindruck als Oberbegriff vonRumlichkeit and Halligkeit, Erluterungen des

Raumeindrucksmasses R. Acustica, 1978, 40, 277-290. (a)Reichardt, W., Schmidt, W., Lehmann, U., & Ahnert, W. Definitionand Messgrundlagen als Mass fr den Raumeindruck beiMusikdarbictungen. Zeitscbrift ftir elektroniscbe Informations- and

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Energietecbnik, 1974, 4, 225-233.Stevens, S. S. (1957).. On the psychophysical law. PsychologicalReview 64(3):. pp. 153181.



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2013 www.dynamic-psychology.euwww.psicologiawww.psicologiawww.psicologiawww.psicologia----dinamica.itdinamica.itdinamica.itdinamica.itwww.dynamicwww.dynamicwww.dynamicwww.dynamic----psychology.eupsychology.eupsychology.eupsychology.eu

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Conf.Dr.Conf.Dr.Conf.Dr.Conf.Dr.LUCHIANLUCHIANLUCHIANLUCHIAN

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Room acoustics and psychophysics

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