Constant Hak

Eindhoven University of Technology | TUE · Department of Built Environment

Microwave Cavity Resonance Spectroscopy is introduced and demonstrated as a new approach to investigate the generation of acoustic waves by a pulsed radio-frequency driven atmospheric-pressure plasma jet. Thanks to recent advancements to the diagnostic method, the lower detection limit for pressure changes in air is ∼ 0.3 Pa. Good agreement with co...

Part of the Ancient Acoustics research project was to measure a dense grid of impulse responses in three ancient amphitheatres in accordance with the ISO 3382 standard. In this conference paper, the measurements performed in the theatre of Epidaurus at 264 receiver positions are used to study the “signal” to “noise” ratios (SNR) for typical low ene...

The acoustics on stage has been recognized as an important design consideration for concert halls and other performance or rehearsal spaces. Stage acoustic parameters such as STearly and STlate are used to judge the early and late reflected sound levels on the stage. However, correlation of these parameters to perceptual attributes have not always...

Stage acoustic parameters aim to quantify the amount of sound energy reflected by the stage and hall boundaries and the energy decay over time. In this research, the effect of orchestra presence on parameter values is investigated. The orchestra is simulated by dressed mannequins, which have been compared with humans with respect to acoustic proper...

Selecting an appropriate method for measuring 'normal' indoor concert hall acoustics is always a trade-off between time, stimulus type, number of measurements and measurement quality. For ISO 3382 room acoustic parameters to be derived accurately from impulse responses, this trade-off aims at a certain minimum decay range. Previously, there have be...

In the last decades we have seen an increased interest in the acoustics of ancient Greek and Roman theatres and much research has been performed on many of them. Research has mainly focused on modelling the acoustics of theatres and has shown various acoustical effects. However, only a limited number of in situ measurements have been available to v...

The stages of ancient theatres can be characterized by their circular shape called the 'orchestra', in front of a rectangular elevated stage with a highly decorated back wall. During some performances , a group of musicians was located in the circular shape, while actors were positioned on the elevated stage. In modern concert halls or theatres, ac...

Acoustic models of ancient theatres found in literature are often based on assumptions, both for geometrical and material properties. The influences of these assumptions on modelling results have been assessed in this paper, which is part of the Ancient Acoustics project. Acoustical measurements were conducted in the Odeon of Herodes Atticus, the t...

Since the beginning of concert hall acoustics research it is quite difficult or almost impossible to find or arrange an opportunity to do extensive measurements with audience present, shortly before the beginning of a symphonic concert or during a break. It is always a trade-off between time, type of signal, number of measurements and measurement q...

Some room acoustic parameters require the sound power of the sound source. The Sound Strength G uses the free field sound pressure level at 10 meters distance as a reference value. Speech intelligibility parameters like the A-weighted Speech Level, Lp,A,S, 4 m, and the Speech Transmission Index, STI, can require an absolute source level defined at...

Musicians in a symphony orchestra rely on the direct and reflected sound on a concert hall stage to be able to hear each other. Besides ensemble conditions, members and directors of symphony orchestras are concerned about the noise levels musicians are exposed to. However, the actual contribution of the different parts of the sound field cannot be...

Adapting the built environment to the needs of nursing- or care-home residents has become common practice. Even though hearing loss due to ageing is a normal occurring biological process, little research has been performed on the effects of room acoustic parameters on the speech intelligibility for older adults. This article presents the results of...

Room acoustical properties in music and voice recordings such as reverberation, definition, clarity and speech intelligibility are influenced by the acoustics (including electro-acoustics) of the listening room. Playing back recorded acoustics through loudspeakers in sound control rooms, lecture rooms, congress halls or cinemas affects the intended...

The noise exposure of symphony orchestra musicians has many different contributions. While playing in the orchestra, measurement devices cannot discriminate between different contributions of different sound sources. When playing at home, rehearsing individually, the own instrument's sound is amplified by the room differently. To investigate how mu...

In 2012, new room acoustic parameters for open plan offices were introduced in the ISO 3382-3 standard. While concepts like the spatial decay rate and speech privacy have been used already in judging open plan office designs, now the standard provides an internationally agreed measurement procedure. Four single number ratings are proposed: the deca...

To achieve a preferable sound field in traditionally shoebox-shaped sports halls, the sound absorbing material is often applied in the upper part of the hall. The applicability of predicting the acoustics of sports halls by three different acoustic calculation methods is investigated: a diffuse field method, a geometrical acoustics method and a ful...

A substantial amount of research has been devoted to producing a calculation model for air absorption for pure tones. However, most statistical and geometrical room acoustic prediction models calculate the reverberation time in full octave bands in accordance with ISO 3382-1 (International Organization for Standardization, 2009). So far, the availa...

IEC 60268-16 describes how to measure the Speech Intelligibility Index STI and its simplified derivatives such as STITEL and STIPA, using two measurement techniques. The first and oldest technique is based on a set of modulated noise signals used as a stimulus. The second method uses impulse responses obtained from maximum length sequence (MLS) or...

The Early and Late Support parameters (STearly and ST late) are used to describe acoustic conditions on stage. Recently, extended Support parameters have been introduced which can be measured at various distances: STearly, d and STlate, d. This way, the amount of reflected sound energy can be studied for sound paths with distances between source an...

From experience and earlier investigations it is clear that room acoustical details in recorded music or speech can only be heard in a room having a reverberation time shorter than the one in the room in which the recording was made. The acoustical properties of listening rooms influence the perceived acoustics of the recording. In earlier investig...

The amount of sound exposure of musicians within a symphonic orchestra is dependent on a large number of aspects. Among these aspects are the many different musical instruments and the impact of room acoustics by the reflected sound. However, it is impossible to obtain separately the contribution of each different aspect from the individually measu...

Standards for measuring room acoustic parameters, such as ISO 3382, in many cases do not, or only partially, specify the requirements that a measured impulse response should meet to allow calculation of a certain parameter. Among other things, it is often left to the user of the standard to find a practical interpretation of the time infinity that...

The most widely recognized objective stage acoustic parameters are the Early Support (STearly) and Late Support (STlate). In these parameters the early and late reflected sound energy is measured within a certain time interval. Different time interval limits have been proposed for the stage acoustic parameters but there is no agreement on the prefe...

An omnidirectional sound source is commonly used in room acoustical measurements. The omnidirectional directivity is usually approached by placing 12 loudspeakers in a regular 12-face polyhedron, called a dodecahedron. In the ISO 3382-1 standard on the measurement of room acoustical parameters, limits are imposed on the maximum allowable deviation...

Members and directors of symphonic orchestras are concerned about the noise levels musicians are exposed to and their ease of playing ensemble. The results of many research has shown that the noise levels within an orchestra can be high. Also, research has shown that the sound level will vary between different musicians playing different instrument...

The available stage acoustic parameters measure the energy ratio between certain time intervals derived from an impulse response. The parameter time intervals may be based on typical sound paths on a stage. A study of typical sound paths and their time intervals indicates that a transition time point may exist between early reflected sound and late...

Live recordings of music and speech in concert halls have acoustical properties, such as reverberation, definition, clarity and spaciousness. Sound engineers play back these recordings through loudspeakers in sound control rooms for audio CD or film. The acoustical properties of these rooms influence the perceived acoustics of the live recording. T...

The sound strength G is a room acoustical parameter used to investigate the sound distribution in a hall or to compare the loudness between different halls. ISO 3382-1 describes several methods to measure G. The accuracy of a G measurement depends on the accuracy with which the power level of the sound source can be determined or with which the mea...

Live recordings of music and speech in concert halls have acoustical properties, such as reverberation, definition, clarity and spaciousness. Sound engineers play back these recordings through loudspeakers in sound control rooms for audio CD or film. The acoustical properties of these rooms influence the perceived acoustics of the live recording. T...

Since a few years a lot of research focussed for better understanding the acoustics on a stage of a concert hall for symphonic music with respect to the ease of playing ensemble and the way the conductor hears the orchestra. As a result of a study in Danish Concert halls dr A. Gade developed the Early and Late Support. These parameters seem very va...

The sound strength G is a room acoustical parameter used to investigate the sound distribution in a hall or to compare the loudness between different halls. ISO 3382-1 describes several methods to measure G. The accuracy of a G measurement depends on the accuracy with which the power level of the sound source can be determined or with which the mea...

Since a few years a lot of research focussed for better understanding the acoustics on a stage of a concert hall for symphonic music with respect to the ease of playing ensemble and the way the conductor hears the orchestra. As a result of a study in Danish Concert halls dr A. Gade developed the Early and Late Support. These parameters seem very va...

The reverberation time and the background noise level are often used as the most important design parameters in European open plan offices to achieve a comfortable acoustic climate and to control speech intelligibility. Good speech intelligibility is desired for people working together, but bad speech intelligibility is desired between independent...

The sound effects and voices that are heard in motion pictures are often replacements or additions of sounds recorded in a Foley Studio. In this type of studio, named after Jack Foley the pioneer in sound effects recording, many objects like wooden floors and doors are present to record sounds from. These recordings need to sound as they are heard...

As presented at Acoustics'08 Paris, the need for an objective parameter proved to be necessary being able to optimize stage conditions (canopy position) for musicians as well as for the conductor. To be able to further develop and validate such an objective parameter measurements have been carried out on 7 stages of concert halls in the Netherlands...

One of the parameters for an objective measurement of the acoustical spaciousness in a room is the IACC. According to ISO 3382-1 this parameter must be measured using a head and torso simulator (HATS). According to the same standard, all other room acoustical parameters (related to loudness, reverberation, clarity and speech intelligibility) must b...

In the previous paper 'New (stage) parameter for conductor's acoustics?' a new parameter (LQ7-40) has been defined. The research with respect to this parameter was presented at ICA2007 in Madrid and at Acoustics'08 in Paris. As elucidated, the objective measurement results for LQ7-40 seem to correspond with the subjective perception of the musician...

The reverberation time and the background noise level are often used as the most important design parameters in European open plan offices to achieve a comfortable acoustic climate and to control speech intelligibility. Good speech intelligibility is desired for people working together, but bad speech intelligibility is desired between independent...

Standards for calculating room acoustical parameters, such as ISO 3382, in many cases do not, or only partially, specify the requirements that a measured impulse response should meet to allow calculation of a certain parameter. For instance, to determine the reverberation time, clear requirements are stated with regard to the exponential shape of t...

Recordings of music, speech or other sounds have acoustical properties, such as reverberation, definition and clarity. For educational, engineering or entertainment purposes these recordings are often played back through loudspeakers in listening rooms, such as classrooms, recording studios or cinemas. The acoustical properties of a listening room...

Most statistical and ray-tracing computer models take into account the absorption of sound by air when calculating the reverberation time. Extensive research by many scientist lead to the standardized calculation model for pure tone air absorption. The phenomenon was discovered from a room acoustical point of view by Sabine, while the further devel...

To compare the acoustic performance of a building element with the given sound insulation requirements, measurements need to be done. Generally, a broadband noise source is used according to international standards. This method does not always work in practice due to high sound insulation values or high background noise levels. It is very inconveni...

A room acoustic impulse response can be used to derive the reverberation time and other parameters. For this a certain minimum energy decay range or effective signal-to-noise ratio is required, which relates to the difference between the initial signal level and the noise level. An impulse response parameter called INR is presented as an estimator...

For musicians, people 2th trained hearing, finding a good 'balance' within the symphonic orchestra is essential. The right balance can be found by the 'trial and error'-method, for example by changing the sage arrangement (sage risers). However it is unknown to what exent sage acoustics are affected by sage risers. This study was aimed at determini...

In a recently constructed concert hall in The Netherlands (14400 m3, 1250 seats), problems were encountered with solo piano performances. Music critics wrote that the instrument sounded unclear and appeared to be swimming in space. A 52‐m2on‐stage wooden reflector and a 90‐m2curtain along the front wall, both removable, were applied to increase cla...