Acústica y Patrimonio

En los últimos años se ha puesto de manifiesto la creciente importancia del patrimonio cultural, reflejada en los programas de recuperación que pretenden mantener, utilizar y conservar el legado histórico y en concreto con la puesta en valor de iglesias y otros espacios de culto. No siempre las condiciones acústicas han sido consideradas en estos programas, lo que ha provocado algunos rotundos fracasos funcionales en la rehabilitación de espacios significativos. Tal vez por ello, no sólo han pasado a situarse en un plano relevante estas condiciones, sino que su conocimiento empieza a considerarse como una nueva aportación a la riqueza patrimonial del recinto, al incorporar al mismo la valoración acústica, frente a la óptica tradicional estilístico-formal, lo que supone una contribución al conocimiento y difusión al incluir estos aspectos al patrimonio inmaterial asociadoIn recent years, the growing importance of cultural heritage has come to light, as reflected in recovery programmes which aim to maintain, use and preserve historical legacy, specifically with the enhancement of churches and other places of worship. Acoustic conditions have not always been considered in these programmes, which has caused some resounding functional failures in the rehabilitation of spaces of significant cultural value. Perhaps for this reason, not only have these conditions reached such a high degree of importance, but knowledge into these conditions through the incorporation of an acoustic assessment is also beginning to be seen as a new aspect of the rich heritage of these types of enclosures as opposed to the traditional stylistic-formal perspective. Hence, a contribution towards knowledge and diffusion of acoustic conditions is made by including these aspects into the associated intangible heritag

Acoustical Behavior Of Churches: Mudejar-Gothic Churches

Christian churches have traditionally been considered to have very good acoustical behavior. This unfounded belief has led to important en-on in church rehabilitation works, especially when the church is to be used subsequently as an auditorium or theater; this is the case of many churches in Spain. Our research group has worked in acoustical analysis for more than ten years. We have participated in many cases of church rehabilitation and have had the opp&unity to achieve surprisingly good acwstical behavior in several. We deal with a very common type in southern Spain: Gothic-Mudejar churches, which have a small volume, a triple-nave layout, and wooden ceilings

Virtual reconstruction of spanish cathedrals: the sound of choir and other weakly coupled volumes in Seville Cathedral

The paper takes advantage of a recent detailed survey of Spanish Cathedrals to investigate the acoustic differences between choir and other weakly coupled volumes in very large spaces. Experimental measurements carried out in a limited number of source-receiver combinations confirmed the existence of double slope behaviour, which markedly influences such spaces. The analysis of the impulse responses was carried out by means of Bayesian parameter estimation, in order to correctly identify the individual decay times. The subjective effect of such coupling was first discussed, showing that having steeper initial decay may significantly contribute to clarity and intelligibility without affecting reverberation. Then, in order to better clarify the role of the architectural features defining such spaces, a geometrical acoustic model of the Cathedral of Seville was performed and a more refined analysis was carried out by analysing a tightly spaced grid of receivers inside the sub space and investigating point by point variations. Results showed that further variations appeared inside the sub-volume, depending on source receiver distance, but the double slope behaviour was clearly visible and characterised the listening experience inside the choir

Objective measures of spatial sffects in Spanish concert halls

The present work consists of a statistical study of the monaural (lateral-reflection fractions and level)and binaural acoustic parameters (inter-aural cross-correlation coefficients) that evaluate the amount ofearly and late lateral acoustic energy encountered in 9 performance halls in Andalusia (southern Spain).Hall volumes range between 6,163 m3and 34,594 m3and all enclosures are used for presentations of symphonic concerts and other music performances. The majority of these venues are located in provincial capitals of the community and often constitute the only premises in the city where symphonic concertscan be held. The acoustic parameters under study here were derived from impulse responses analyses using a sine-sweep signals which were generated and processed by WinMLS 2004 software in the octave-band frequency centred from 125 to 4 kHz, and all parameters were spectrally averaged according to theISO 3382-1 standard. A comparison is presented of monaural experimental results as a function of source-receiver distance with the prediction of Barron’s revised theory for concert halls, and the analyses of the acoustic parameter results are carried out in terms of their respective just noticeable differences: at the many microphone positions for the two source positions on stage, for the spatial distribution of seats in the audience zone relative to the central axis (for left- and right-hand sides) of the rooms, and for the presence of the orchestra shell on stage. Results reveal that the orchestra shell propitiates a perceptible decrementin the values of the early lateral energy fraction and an increment in the late lateral level at the audience seats. In addition, a regression study reveals that the two kinds of measures of laterality, monaural andbinaural, are correlated when the hall-average data is considered, but they remain uncorrelated when all individual positions are used. Like wise, the ranges of variation of the acoustic parameters found in thesehalls are narrower than those specified in the ISO 3382-1. The paper concludes with a discussion on the relationships of hall-average data of the five parameters with eight geometric and acoustic variable

Virtual acoustics of the Cathedral of Cadiz

Among heritage buildings, cathedrals best reflect European cultural identity. In addition to litur-gical activities, with the concurrence of the faithful, cathedrals, in spite of their long reverbera-tion times, develop other cultural activities, with a large audience, and have become spaces of the utmost interest for tourism, with a massive influx of tourists. This paper presents a summary of the Final Degree Project in Fundamentals of Architecture of the first author and describes the process of architectural analysis of the cathedral of Cadiz towards the development of a virtual model of the site. The simulated results are compared with those measured in situ for the preeminent position of the source: the high altarEntre los edificios patrimoniales que mejor reflejan la identidad cultural europea están las catedrales. Además de las actividades litúrgicas, con la concurrencia de los fieles, en ellas se desarrollan, a pesar de sus largos tiempos de reverberación, otras actividades culturales, con numerosa audiencia, y se han convertido en espacios del máximo interés turístico, con masiva afluencia de turistas. En este trabajo se hace un resumen del Trabajo Fin de Grado en Fundamentos de Arquitectura del primer autor. En él se describe el proceso de análisis arquitectónico de la catedral de Cádiz con el objetivo de elaborar un modelo virtual del recinto y se comparan los resultados simulados con los medidos in situ, para la posición preminente de la fuente sonora: el altar mayo

Exploring the acoustics of ancient open-air theatres

The theatres of Antiquity, Greek and Roman, constitute public buildings of the utmost importance inthe history of Western culture and in universal cultural heritage. Many of these spaces are being used fortheir original function with or without only minor adaptations. If they are well preserved and/or restored,these performance buildings attract large audiences to representations of classical and contemporary plays,thereby serving the purpose for which they were built in the Ancient Age. These theatres bear witnessto the existing relationship between architectural work, visual and acoustic experience, and dramatic art.Although the majority are located in the Mediterranean region, these structures were also built in themajor cities of the ancient world in Europe, the Middle East, northern Africa, and beyond. This paper aimsto summarise and critically review research published in the literature regarding their acoustic aspects,with particular emphasis on Roman theatres. These pieces of research emphasize the importance of thediffraction of sound in the tiers of thecaveaand the good intelligibility for speech of the Greco-Romantheatre

An analytical model for evaluating the sound field in ghotic-mudejar churches

Acoustic correction in churches that arc part of our historical and architectural heritage is asubject of great importance and interest today in the field of applied acoustics. This paper deals witha type of church that is often seen in southern Spain: Gothic-Mudejar churches from the thirteenth tofifteenth century period. To be precise, this study of the sound field of these churches is meant toobtain an analytical model that will allow us to quite accurately predict the sound presure levels fordifferent octave bands. Also, this is compared with other analytical models, mainly Barron's mode

Correlations of the acoustic fields of mudejar-gothic churches

This paper studies the statistical correlations between monaural acoustic parameters withthemselves and with architectural parameters from an acoustical survey undertaken in 12Mudejar-Gothic churches in Seville, southern Spain. Objective room-acoustic parameters havebeen measured using impulse response analysis through a maximum-length-sequencemeasurement system in each church. Measurements cover time parameters (reverberation time,early decay time); levels (sound strength); energy-based parameters (centre time, clarity forspeech, clarity, definition, early lateral energy fraction); and speech intelligibility (rapid speechtransmission index) and the analysis takes into account both spatially averaged values andindividual positions. The aim of the study is to identify the main architectural factors that haverelevant influence on the acoustic fields of the churches, and the minimum number of roomacoustic parameters which are able to describe adequately this acoustic field, thus the possibleexcess of information is evaluated. Significant correlations have been found that, in the bestcases, correspond to fits using pairs of independent variables instead of one single variable. Thebest option to describe the six subjective attributes of sound perception in these buildings consistsof three acoustic parameters formed by two different pairs plus the early lateral energy fractio

Measured acoustic parameters versus predicted ones in two mudejar-gothic churches

In this work we have undertaken an acoustic simulation of the sound field in two churches in the historical centre of the city of Seville. The simulation has been carried out through the CATT-Acoustic v7.2f programme, which has been based on the reverberation times measured in those spaces. We have focused on Sound Pressure Levels Lp, Clarity C80, Definition D50, and RASTI indices data in relation to their spectral variations and spatial distributions and their comparison with the equivalent experimental result

Comparative study of various techniques to measure speech intelligibility

The aim of this paper is to compare two different methods of measuring the Modulation Transfer Functions (MTF) and the corresponding derived STI-RASTI indices to assessing intelligibility. The first method uses, as test signal, a band filtered (500 and 2000 Hz) amplitude modulated noise. The second one uses MLS signals to obtain the impulse response of the system; further post processing allows us to calculate the MTF and STI-RASTI indices from this filtered respons