About REVERBDATA
REVERBDATA is a database of acoustical information (Room Impulse Responses – RIR) of significant Portuguese spaces. These spaces are selected based on their importance from the acoustical, architectural, cultural, and functional points of view. Multi-channel RIR are being registered at several locations inside the selected spaces, processed and fed to the database, providing a GUI for navigation and for artificial reverberation generation. Using advanced and optimized measurement and processing techniques, impulse responses under different multi-channel formats are being acquired for subsequently allowing immersive and accurate sound reproduction through FFT convolution reverb. RIR databases have been developed and explored in audio and acoustics, providing a valuable collection of measured or simulated responses that almost completely describe the acoustic characteristics of different spaces.
The data is divided into architectural documentation, acoustic records with associated specific information and photographic materials. Regarding acoustic acquisitions and recordings, raw audio containing the sweeps and in situ recorded RIR is available, as well as post-processed audio containing the optimized, noise-free responses. The RIR are subdivided into two categories, the first containing the stereo and binaural responses (in 4-channel wave files) and the second containing the Ambisonics responses in formats A and B. In the latter case, the responses are available in the FUMA or ACN/ formats. AMBIX. Stereo-binaural responses are available normalized to the maximum value ±1 or scaled according to source-receiver distances. For some spaces, mono impulse responses acquired using ARTA software (v1. 9.7) are also available in the database. For each post-processed RIR, the main objective parameters describing the acoustic quality of the space (wideband and octave band values) are available in an associated .txt file.
What is a Room Impulse Response?
A Room Impulse Response (RIR) is like an acoustic photograph of a space. It contains the complete information on how the sound is heard and perceived inside the space due to reverberation.
Reverberation is a common auditory phenomenon experienced daily, resulting from sound interacting with the surrounding environment. This effect, that is particularly audible in enclosed spaces due to the numerous echoes arising, is often artificially incorporated into electronically recorded and produced music, as well as other media like cinema, virtual reality applications, and computer games. Using RIRs together with a technique called convolution reverb we can obtain the exact acoustic sense experienced in real spaces.
Portuguese Spaces
Acknowledgments
The authors thank all entities that have provided access to their spaces, allowing for setting up REVERBDATA.
We thank all students of Music Technologies who have participated in REVERBDATA.
IPL/IDI&CA2023/REVERBADATA_ESML
Calouste Gulbenkian Foundation
Grand Auditorium
The Grand Auditorium of the Calouste Gulbenkian Foundation in Lisbon had its inaugural concert on the 3rd of October 1969, the day after the official inauguration of this complex. With exceptional acoustics, its design and construction were aimed at hosting many cultural activities, including symphonic and choral-symphonic music, congresses and conferences, ballet, theater and cinema. The hall was designed by the Portuguese architects Alberto Pessoa, Pedro Cid e Ruy d’ Athouguia and by the British acoustician William Alexander Allen. Renovated in 2014, with ARUP as acoustic consultant, the Great Hall has a capacity for 1203 people, spread over 36 rows on 3 different levels.
Cartuxa Monastery
The project for a New Church was born with the general plan of the Monastery of D. Basílio de Faria, Prior of Vallis Misericordiae between 1613 and 1621. However, the construction of the Church was dragged into a second phase of works, as the need was imposed of the construction of the Hermitage. About a century later, in the priory of D. Luís de Brito (1716 – 1746), the economic conditions came together to allow progress with the second phase of construction of the New Monastery, largely thanks to the alms collected by Gregório dos Santos in Brazil , who began arriving in Laveiras in 1727. On March 25, 1733, a second blessing of the Church took place and the first stone of the construction was laid, in the presence of the first patriarch of Lisbon, D. Tomás de Almeida. According to some authors, the works themselves began in 1736. In that year, Frei Gregório managed to raise another 99,800 reis from benefactors in Portugal and the Monastery received a generous contribution from King D. João V for the works on the New Church.
From Guerin, A.; Marrinhas, M. L.; Bulhões, D. , “Santa Maria Vallis Misericordiae – A Cartuxa em Oeiras”, Municipality of Oeiras, Oeiras 2023.
Church
In 1746 the Church was already built and in use, with only the main chapel panel missing, and on the frontispiece the niche of Our Lady and the fires at its top, which was soon completed. The New Church is built to the south of the Hermitage and aligned with its axis, in tradition of the monastic architecture of the Order of Saint Bruno. To the west is the Small Cloister and its facilities for monastic community life. The architecture and distribution of the spaces of a Carthusian Church are at the service of a cult that obeys specific rules and statutes of the Order of St. Bruno, which is why the space presents characteristics specific to the Order.
The church, with a wide limestone facade, is topped by an image of the Virgin and Child and was built in the 18th century. Due to its excellent acoustics, this space has regularly hosted concerts by the Lisbon Metropolitan Orchestra and the Cascais and Oeiras Orchestra.
Coliseu Micaelense
Located in Ponta Delgada city, is the largest entertainment hall in the Autonomous Region of the Azores. Built in 1917, it was purchased, renovated and reopened by the Ponta Delgada City Hall in 2005. It can host a wide variety of events, including shows in a conventional auditorium and shows in a circus arena, even shows such as café-concerts, rock concerts, banquets, casino, congresses, fairs and dance balls.
Convent of Christ
The Convent of Christ is a UNESCO Heritage of Mankind monumental complex in the city of Tomar, having been continuously built between the 12th and 16th centuries. Known for its Templar history and diverse architectural styles, it is of undeniable cultural and archaeological importance.
Nowadays it is permanently open to the public and occasionally it hosts educational and artistic exhibitions as well as cultural events such as concerts and plays.
The acoustic acquisitions and records were done in the Church of the Convent (Charola – Round Church and Main Body), Main Cloister (D. João III), Refectory and Cistern (of the Crows’ Cloister), allowing for a rather complete and unique heritage preservation of the monument’s acoustics.
Charola – Round Church and Main Body (3rd Floor)
Located on the 3rd floor, the Church of the Convent of Christ is made up of the Charola (or Rotunda) and of the Main Body of the church.
The Charola dates from the 12th century and is an early Templar Romanesque fortified oratory inspired by the Temple of Jerusalem, having its capitals on the central columns and the painting on stone allusive of St. Christopher, dating also from that period. The Main Body, built in the Manueline style from 1510-15 by Diogo Arruda and João de Castilho, includes the nave, the upper choir and the lower choir, and is joined to the Charola by means of an arch opened in the walls of the old oratory. The inner drum of the Rotunda would be turned into a chancel.
Between 1510-15 King Manuel I also commissioned the decorative interior of the Church, adding stucco, carved woodwork and the fresco and secco paintings. From that period are the wooden statues in the chancel and the upper choir stalls, now gone, by the Flemish sculptor Olivier de Gand and completed by Fernão Munhoz, and also a set of monumental wooden boards executed by the royal painter Jorge Afonso. The paintings on the peripheral altars of the Charola, by Gregório Lopes (1536-38) would also be added during the 16th century, as well as the decoration on the triumphal arch by Domingos Vieira Serrão and Simão de Abreu (1592-97).
Main Cloister D. João III (1st Floor)
The Main Cloister (D. João III) is the magnum opus of the Renaissance convent built by King D. João III, outside the castle walls, and surrounding the nave with which his father, D. Manuel I, expanded the Templar church.
It is part of the group of four large cloisters around which the formal structure of convent space is based. Adjacent to the Church of the Convent, the D. João III Cloister flanks the south façade of the Manueline nave. Its design is different from the rest of Castilian convent architecture. Remade after the death of Diogo de Castilho, by Diogo de Torralva, in the Mannerist style of the Italian Cinquecento, this cloister will feature a graceful water fountain, from Fernandes Torres, fed by water from the conventual aqueduct. It is considered a masterpiece of the European Renaissance.
Refectory (1st Floor)
The Refectory, built by João de Castilho during the great campaign of King João III, was probably finished between 1535 and 1536, according to the inscriptions on the pulpits that were reserved for reading during mealtimes.
It has very interesting vaulting ribs. The antechamber served as a pantry and gave access to the kitchen. The wine and olive oil cellars lay below the refectory, as did other rooms of agricultural nature, connected to the orange grove (Friars’ Garden) and the Convent enclosure. The present arrangement of the tables was due to later work, from the time of the Missions Seminary (Seminário das Missões), 1922-92.
Cistern of the Crows’ Cloister (Basement)
The Cistern (of the Crows’ Cloister), built between 1543 and 1546 by João de Castilho, was probably used for irrigation. Castilho himself called this space the barn cloister. The Cistern has exclusive access via a small staircase, close to the door to the friars’ kitchen.
The quadrangular shaped Cistern has two double arcade galleries separated by buttresses, which rise to the 3rd register to the south and west, and coverings and supports identical to those of the Cloister of Micha. The block is surrounded by 4 bodies of 3 floors, with the south side occupied by the old granary (today the chapel), the north by the kitchen (ground floor) and the novitiate cells (1st floor) and the east side by the Refectory and the cells on the south arm of the dormitories.
Lisbon School of Education
It can be considered that the roots of Lisbon School of Education (ESELx) date back to the portuguese reign of D. Luís and the year 1862, when the Lisbon Primary Normal School was created. Installed in the Palace of the Marquises of Abrantes, in Marvila, this School admitted only male students. The Female Normal School, located in Calvário, began its activities in 1866. From 1914 the two Normal Schools merged and began to operate under a co-education regime, in its own building, located at Quinta de Morocco in Benfica, in the 1919. This is the building where the Lisbon School of Education is located today. This building has been undergoing restoration, maintenance and recovery works, which have allowed the spaces to be adapted, monetized and improved, making them more functional and consistent with the activities that the School carries out. ESELx only began its activities in 1985 with the appointment of the Installation Committee. For eight years, from 1985 to 1993, the School developed activities in the various fields of intervention assigned to it – initial, continued and specialized training; professionalization in service; research, research and development; provision of services to the community – together with the tasks inherent to the installation regime. On January 1, 1994, following the approval of the School’s statutes, the Board of Directors, elected by members of the school community, took over.
From ESELx site (“history”)
Great Hall
Located at Lisbon School of Education, has a maximum seating capacity for 300 persons and allows a variety of cultural events such as theatre, cinema, concerts, and conferences. The hall has a flat audience area, with individual chairs, and a circular shape balcony.
Lisbon School of Music
Lisbon School of Education (ESML) was created in 1983 following the reconversion of the National Conservatory, having been integrated into the Polytechnic Institute of Lisbon in 1985. ESML assumes as its mission the artistic, technical, technological and scientific training, at the highest level, of professionals in the Music area. It presents itself, on the national and international scene, as a reference school, which is based not only on its origins and the recognized quality of its international-level teaching staff, but also on the dynamics, diversity, projection and prestige of its achievements. artistic in the fields of artistic production and dissemination, teaching and research, which illustrate and embody its commitment to the constant search for excellence, openness to innovation and contemporaneity. Located on the IPL Benfica Campus, it has facilities of recognized international architectural prestige, as well as equipment suitable for its training activity. In pursuit of its mission, it promotes a teaching/learning environment equipped with the highest standards of demand and quality, guiding students towards their development with a view to entrepreneurial, nationally and internationally competitive and socially relevant professional performances in the areas of Arts and Music Industries.
From ESML site (“about us”)
Great Hall
Also called Vianna da Motta Auditorium is located at Lisbon School of Music. This room was designed by the Portuguese architect Carrilho da Graça and by the Belge acoustician Daniel Commins. The stage possesses a flat wooden floor on joists, the audience area is tilted approximately 20º in relation to the horizontal plane and has two wooden flights of stairs in between the rows of chairs. The walls surrounding the audience go continuously around the stage in a roughly trapezoidal shape and consist entirely of large-scale shape-optimized reflection phase grating diffusors.
Small Hall
Located at Lisbon School of Music, this hall was designed by the Portuguese architect Carrilho da Graça. It has a seating capacity for 58 persons, with features that gives it versatility to host various cultural events, like music, conferences, theater, dance, and cinema.
Organ Room
Located at Lisbon School of Music, this room is specific for organ music practicing and rehearsal, it also holds periodic performances for small groups.
Lourinhã Mercy Church
The Lourinhã Misericórdia Church dates from 1626, and its construction date is inscribed on the tympanum at the entrance. The facade of the church has a pointed gable, and the door is surmounted by a triangular tympanum, where the date 1626 and the phrase: “Blessed are the merciful, for they shall obtain mercy” are inscribed. In the building where the church is located, there is a Manueline portal of great artistic value, which belonged to the Chapel of the Holy Spirit.
The Church is currently part of the Museum Space of the Santa Casa da Misericórdia da Lourinhã. This space, in the heart of the village, presents a collection of inestimable value, with works of sacred art, liturgical objects and extremely relevant historical information to understand the role of the Santa Casa da Misericórdia as an active part in the development of the village of Lourinhã, over the last 450 years.
Lux Frágil
Disco Room
A famous nightclub located in Lisbon that opened on the 29th of September 1998. Lux Frágil, besides being a bar and disco, has hosted concerts, performances, exhibitions, book presentations and recordings and was even on the set of many television programs.
National Theatre D. Maria II
Garrett Hall
Is the main hall of the National Theatre D. Maria II in Lisbon. The Garrett Hall was designed by the Italian architect Fortunato Lodi in a classic horseshoe shape and opened at 13th April 1846. In 1964, the theatre was destroyed by a fire, which led to a full reconstruction of the building, inaugurated in 1978. The restoration project focused on providing the best possible acoustic conditions, aiming at a 1 second reverberation time. Nowadays this hall is still mainly used for theatre performances, thus maintaining its original purpose.
St. Dominic Convent
Church
Inaugurated on the 21st of March 1994 by the Dominican Order as the first male catholic convent built in Lisbon since the last 250 years. Designed by Portuguese architects José Fernando Gonçalves and João Paulo Providência, it is a modern church of sober and minimalist lines, with a rectangular shaped floor and a considerable large height. The space has a large window that opens onto the inner cloister, the floor is slightly inclined towards the altar and its interior decoration is also very minimalistic, without figures or images.
St. George Cinema
Manoel de Oliveira Room
The main hall of this cinema in Lisbon is called Manoel de Oliveira (after the famous Portuguese filmmaker). The cinema opened in 1950 and was remodeled several times, the last refurbishment took place in 2001. It is a hall with a seating capacity for 830 persons divided into 3 audience stalls.
Technical Details
Acquisition Equipment
The acquisition procedure in terms of the used hardware and software has thus become now more or less stable. The following equipment has been used:
Source:
Lookline DL-303 omni dodecahedron loudspeaker.
Microphones:
2 Earthworks M30 omnidirectional measuring microphones,
1 Binaural Enthusiast B1-E dummy head with BE-P1 microphones,
1 Sennheiser Ambeo VR microphone,
1 Zylia ZM-1-3E 3rd order Ambisonics microphone.
Audio Interfaces:
Steinberg UR44, ESI U108PRE.
Software:
Custom scripts and functions in GNU Octave 6.4.0 using double precision FP arithmetic, developed in the last years by the authors
Acquisition Procedure
The dodecahedron loudspeaker was used for radiating exponential sine sweeps, or synchronized exponential sine sweeps, generated in the Octave software.
The sweeps recorded with the microphone array were registered synchronously through the ASIO compatible audio interface with the Octave software that calculated the corresponding impulse responses: stereo, binaural and 1st order A format Ambisonics (when using the Sennheiser Ambeo VR mic). The sweeps recorded by the Zylia mic were registered with its proprietary software (Zylia Studio) on 19 channel A format Ambisonics wave files and the corresponding impulse responses were also calculated in Octave.
The impulse responses were obtained by deconvolving the recorded sweeps with the inverse signal of the used exponential sine sweep, generated in the Octave software. When synchronized exponential sine sweeps were used, then the deconvolution was done analytically in the frequency domain employing the Fourier Transform of the synchronized swept-sine signal.
The sweeps recorded through stereo, binaural and 1st order Ambisonics mics were digitized with a sampling rate of 96 kHz, except for the two older acquisitions (ESML Great and Small Hall) where a rate of 44.1 kHz was used; a quantization depth of 32 bits FP was used in all cases. For the sweeps recorded with the 3rd order Ambisonics mic a sampling rate of 48 kHz with a quantization depth of 32 bits FP was employed.
RIR Processing
The raw audio as recorded in situ containing the RIRs was post-processed for the purpose of denoising and for converting the Ambisonics A-format responses into convenient B-format responses. Denoising is necessary due to the inherent background noise that is present in the spaces and, to a lesser extent, also in the acquisition chain, that limits the achievable signal-to-noise ratio (SNR). The achieved SNRs (of the order 80 – 90 dB, broad-band) are more than enough for characterization of the spaces using ISO 3382-1 standard room acoustical parameters, but the noise present in the RIRs can still be audible when using them for reverb convolution. The adopted solution consists in truncating all responses before the decay reaches the level of the background noise. The procedure employed for this truncation is based on the so-called Lundeby algorithm, which gives very good results in most cases.
After denoising, the associated main acoustical parameters specified in the ISO 3382-1 standard were calculated for each RIR and stored in text files. The calculated parameters set include signal-to-noise values, reverberation times (EDT, T10, T20, T30, T60), clarity indexes (D50, C50, C80), center times and IACC values in the case of binaural responses.
The conversion of A-format to B-format was carried out in Reaper using the proprietary plug-ins from Sennheiser (Ambeo A-B Format Converter, v1.2.0) and from Zylia (Ambisonics Converter v1.7.0).
Space’s RIR Details
REVERBDATA Articles
- D. Alarcão, A. Couto Pinto – ” The REVERBDATA Room impulse response database“, AES Europe 2024, Madrid, Spain, 15 – 17 June 2024 (https://aes2.org/publications/elibrary-page/?id=22551)
- D. Alarcão, A. Couto Pinto, G. Marramaque, F. Mendonça – ” REVERBDATA – a RIR database of Portuguese architectonic spaces“, TECNIACÚSTICA 2024, Faro, Portugal, 11 – 13 September 2024 (https://www.sea-acustica.es/publicaciones-congresos/)
Contacts
Prof. Dr. Diogo Alarcão
CESEM – Centre for the Study of the Sociology and Aesthetics of Music
ESML – Music Technologies, Lisbon School of Music
IPL – Polytechnic University of Lisbon, Portugal
email: dalarcao@esml.ipl.pt
Prof. Dr. António Couto Pinto
CEDET – Center for Studies and Development of Electronics and Telecommunications
ISEL – Lisbon Engineering Institute
ESML – Music Technologies, Lisbon School of Music
IPL – Polytechnic University of Lisbon, Portugal
email: apinto@esml.ipl.pt
Portuguese