Claus Christensen - Academia.edu (original) (raw)

Papers by Claus Christensen

2021 Immersive and 3D Audio: from Architecture to Automotive (I3DA)

Implementing multi-source auralisations is essential for comprehensive acoustic studies of concer... more Implementing multi-source auralisations is essential for comprehensive acoustic studies of concert halls, operas, restaurants and other spaces, where many sound sources are active. Nowadays, room simulation programs and computers are fast enough to calculate the many impulse responses required for such auralisations, in short time. However, setting up the calculations for the entire ensemble of sources and corresponding signals requires a lot of time-consuming manual work and a large number of recorded source signals. To facilitate the process of creating multiple source signals, with sufficient variation for auralisation, a set of audio effects has been developed in the ODEON Room Acoustics Software [1]. The effects can be combined together and help to create a population of incoherent output signals by varying certain attributes of just a single input signal. Two examples are: a) A group of violins, composed of several signals that have been generated as variations of just one violin recording, using individually randomized Chorus, Spectrum and amplitude effects. b) A number of speech signals with a given output length, created by performing randomized pitch change, tempo shift and random amplitude modulation. The length of the output speech signal can be obtained by time shifting and repeating each of the processed signals with pauses of random length in-between until the desired total length is obtained.

The use of sine sweeps is a robust method to measure room impulse responses. One particular advan... more The use of sine sweeps is a robust method to measure room impulse responses. One particular advantage is that the frequency spectrum of the excitation signal can be controlled in the time domain-by changing the rate of frequency change-while keeping the amplitude of the signal virtually constant over time. The sine sweep approach is adopted in the measurement tool of the ODEON software. In this paper, a method to optimize the measurements is introduced. The spectrum of the sweep signal is modified, making use of a previously measured impulse response and its resulting Schroeder decay curve. The maximum dynamic range of the Schroeder curve is defined as the decay range. This decay range is calculated in octave bands, and its deviation from a broadband average is subtracted from the sweep spectrum magnitude. The goal of this approach is to redistribute the power across frequency bands in order to ensure a more uniform signal-to-noise ratio (SNR). The method is evaluated through experimental measurements. The proposed optimization leads to a more constant decay range across octave bands, with an improved SNR in bands with poor decay. Practical aspects including repeatability and sweep duration are discussed.

A new method has been developed for the calculation of transmission through walls, including aura... more A new method has been developed for the calculation of transmission through walls, including auralization in the receiving room. This has been made as an option in the room acoustic simulation software Odeon version 9. Transmission through multiple walls can be investigated; even walls with different materials on either side and with thickness can be handled. The influence of partial areas with different transmission losses, the volumes of the rooms, and the reverberation times of the rooms are included in the simulation results.

The Journal of the Acoustical Society of America, 1996

Original contributions to the Technical Notes and Research Briefs section are always welcome. Man... more Original contributions to the Technical Notes and Research Briefs section are always welcome. Manuscripts should be double-spaced, and ordinarily not longer than about 1500 words. There are no publication charges, and consequently, no free reprints; however, reprints may be purchased at the usual prices. Error in the calculation of synchronized spontaneous otoacoustic emission frequencies measured with the ILO88 system [43.64.Jb, 43.64.Yp]

The Journal of the Acoustical Society of America, 2005

and it is a condition of accessing publications that users recognise and abide by the legal requi... more and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

The Journal of the Acoustical Society of America, 2008

Geometric computer models for room acoustics, such as ODEON, predict sound fields most reliably a... more Geometric computer models for room acoustics, such as ODEON, predict sound fields most reliably at high frequencies. At low frequencies, algorithms must be modified to account for deviations from geometrical acoustics caused by wave phenomena. For finite reflectors, a common low frequency model is based on the Kirchhoff-Fresnel Diffraction Approximation, which predicts a uniform 6 dB per octave slope below a reflector's geometrical limiting frequency. As discussed in this paper, highly accurate Boundary Element Method simulations, not subject to the Kirchhoff Approximation, suggest the use of an additional, lower limiting frequency and slope of 12 dB per octave to represent the reflector's response at the lowest frequencies. This second limiting frequency and 12 dB per octave slope, referred to as the dipole limiting frequency, are presented in a form suitable for insertion into a geometric computer model. [Work supported by the National Science Foundation.]

Acta Acustica united with Acustica, 2008

This thesis represents a method for reducing the geometry of complex room models to make it possi... more This thesis represents a method for reducing the geometry of complex room models to make it possible to model their acoustics in real-time. It is shown that reducing geometry can vastly decrease the modeling time. This conclusion is supported by the experimental results. The previous work on geometric model simplification is surveyed extensively. The reduction algorithms are grouped into decimation algorithms and surface reconstruction algorithms. The decimation algorithms are categorized into vertex removal, vertex clustering, edge collapsing, and triangle removal algorithms. The surface reconstruction algorithms include re-meshing and volumetric approaches. The main contribution of this thesis is a method for reducing geometric models for acoustics modeling. It consists of two steps: topology simplification and geometry reduction. Two approaches are suggested for the topology simplification, one based on a regular density grid and another based on an octree. There are also two algorithms for the geometry reduction both of which are trying to merge small coplanar triangles into large polygons. The results of the reduction method are evaluated using the acoustical parameters. Also the performance of the reduction algorithm is analyzed. The experiments show that the algorithm preserves spatial properties, measured by the reverberation time, relatively well. The algorithm can produce coarsest level approximations in real-time, but more accurate approximations require significantly longer times for computation.

The correct level of presentation is important for all kinds of auralisation in order to be as re... more The correct level of presentation is important for all kinds of auralisation in order to be as realistic as possible. The method applied in ODEON is approximate, aiming at the A-weighted sound pressure level to match that of the calculation result of the same simulation. A pink noise signal is applied for the calibration. The trick is to create modified versions of the input signals used for auralisation in such a way that the input signals have the same A-weighted level. In order to ensure a proper calibration it is necessary to know the sound power level of the sound source used as input for the auralisation. This can be difficult in some cases and may be the major source of uncertainty in the calibration. Next step is to look at the room simulation that produces the auralisation, and to choose a source-receiver combination to be used for the calibration. The relation between the sound power of the source and the sound pressure level in the receiver position is a result of the roo...

The Roman theatre follows a natural evolution from the Greek theatre combining the acting area an... more The Roman theatre follows a natural evolution from the Greek theatre combining the acting area and the seating area into a single structure. Modifications of stage, orchestra and seating area have resulted in a considerable improvement in the quality of the acoustics. As a part of the ERATO project, the acoustics in Roman theatres and Odea (roofed theatres) have been recreated through computer simulations using the Odeon software. Computer models of five Roman theatres have been created based on data from archaeologists, architects and measurements in situ. The theatres have been modelled in their present state and as they presumably were built in the Roman era; the reconstructed parts of acoustical interest are the stage wall and top colonnade in the open-air theatres and the roof and windows in the Odea. The irregular absorption distribution in these rooms makes them challenging for acoustical simulations differing from traditional concert halls. Auralisation examples will be pres...

This paper presents an extension to the traditional room acoustic modelling methods allowing comp... more This paper presents an extension to the traditional room acoustic modelling methods allowing computer modelling of huge machinery in industrial spaces. The program in question is Odeon 3.0 Industrial and Odeon 3.0 Combined which allows the modelling of point sources, surface sources and line sources. Combining these three source types it is possible to model huge machinery in an easy and visually clear way. Traditionally room acoustic simulations have been aimed at auditorium acoustics. The aim of the simulations has been to model the room acoustic measuring setup consisting of an omnidirectional sound source and a microphone. This allows the comparison of simulated results with the ones measured in real rooms. However when simulating the acoustic environment in industrial rooms, the sound sources are often far from being point like, as they can be distributed over a large space in the room and may indeed contribute surfaces to the room. Examples of such sources could be ventilation...

Multi-channel orchestral anechoic recordings were obtained at the Technical University of Denmark... more Multi-channel orchestral anechoic recordings were obtained at the Technical University of Denmark (DTU) in June 2005. Every orchestral part of specific movements of two symphonies, Brahms’ Symphony No. 4, 3 rd movement, and Mozart’s Symphony No. 40 in g minor, 1 st movement, were digitally recorded using five 0.5” DPA microphones, with four surrounding the musicians in the horizontal plane and the fifth directly above. The recordings were made in DTU’s large anechoic chamber, which has free space of about 1000 m 3 and a lower frequency limit of 50 Hz. Each musician was recorded individually, and to assist with overall synchronization of all recordings, the musicians listened to the piece over headphones and viewed a video of a conductor while playing. In general, for the string parts, two to three individual musicians were recorded, and only one instrumentalist was recorded for the remaining brass, woodwind, and percussion parts. These recordings have been edited for use in room aco...

which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer mo... more which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer model, is in the process of upgrading its ray tracing and scattering algorithm. The new algorithm allows users to specify transmission through reflector panel arrays. To aid in the development of ODEON’s new algorithm, its predictions are compared with predictions from a boundary element method (BEM) model. The computationally intense BEM model is shown to be very accurate in predicting the response from single- and multi-panel reflector arrays. Comparisons will be shown for several reflector arrays of varied size and density. The BEM results have been filtered into octave bands for ease of comparison.

The measured impulse response is often used as a true reference of a real room impulse response a... more The measured impulse response is often used as a true reference of a real room impulse response and geometrical acoustic simulations are considered to be only a crude representation of it. However, both approaches have their own challenges and limitations. Geometrical acoustic models do not include wave phenomena, such as interferences and diffraction, as they simplify sound propagation by rays. The advantages of acoustic simulations with such models include a perfectly omnidirectional and impulsive sound source, no distortion problems, full control of the background noise, and a well-defined onset time of the impulse response. On the other hand, impulse response measurements include wave phenomena, but they do have their own weaknesses, which may cause significant errors in the derivation of the ISO-3382 room acoustic parameters. Due to the presence of background noise in the measured impulse response it is difficult to evaluate which part is valid. In addition, the sound source us...

The measurement of the Sound Strength (G) room acoustic parameter requires a calibration of the m... more The measurement of the Sound Strength (G) room acoustic parameter requires a calibration of the measuring system, so either the sound power of the source or the sound pressure level at a distance of 10 m in free field is known. Two procedures are described in ISO 3382-1: Calibration in a reverberation chamber and calibration in free field in a large anechoic chamber. Both methods require that all conditions in the measuring chain (amplification gains, sound card, cables etc.) remain fixed during calibration and in-situ measurements. This can be impractical mainly because measurements may be performed much later than calibration and at a distant location, and it cannot be guaranteed that the conditions in the measuring chain remain unchanged. In this paper a Two-step calibration procedure is proposed that removes the requirement of fixed conditions of the measuring chain. The procedure adds a second step to the normal reverberation room or free field calibration methods, in order to ...

The application of room acoustic simulations to industrial halls with a large number of sound sou... more The application of room acoustic simulations to industrial halls with a large number of sound sources has been known for many years as an efficient means for noise control. However, the application of the auralisation tool to multi-source environments is rather new. The challenges and possibilities are discussed through a number of examples including a symphony orchestra in a concert hall, crowd sounds in a theatre, and the speech privacy in an open plan office. In order to make this technique a useful tool it is important that the quality and realism of the auralisation is very high, but also that the user interface allows a sufficient overview and control of the whole scenario. Good localisation is particularly important in multi-source environments. For some applications the use of headphones is not possible, so it is necessary that the auralisation can be presented through a surround loudspeaker system.

The use of computer models for acoustical design of auditoria takes advantage of visualization an... more The use of computer models for acoustical design of auditoria takes advantage of visualization and auralization for several purposes, some of which will be presented. The sound absorption characteristics of materials can be visualized by the use of colors of surfaces in a 3D room model. Calculation results displayed as color maps in a grid can give a quick overview of complicated conditions of sound distribution, including the display of acoustical parameters for noise level, sound strength, clarity, echo etc. The dynamic picture of a wave front with thousands of balls emitted from a source and reflected in a room has proven to be a useful tool to understand complicated conditions of sound reflection. Using auralization dynamic phenomena like reverberance, echo, and flutter echo can be auralized by listening to a hand clap. Coloration is another phenomenon that may be auralized by listening to white noise. The multisource auralization of a symphony orchestra where each single instru...

2021 Immersive and 3D Audio: from Architecture to Automotive (I3DA)

Implementing multi-source auralisations is essential for comprehensive acoustic studies of concer... more Implementing multi-source auralisations is essential for comprehensive acoustic studies of concert halls, operas, restaurants and other spaces, where many sound sources are active. Nowadays, room simulation programs and computers are fast enough to calculate the many impulse responses required for such auralisations, in short time. However, setting up the calculations for the entire ensemble of sources and corresponding signals requires a lot of time-consuming manual work and a large number of recorded source signals. To facilitate the process of creating multiple source signals, with sufficient variation for auralisation, a set of audio effects has been developed in the ODEON Room Acoustics Software [1]. The effects can be combined together and help to create a population of incoherent output signals by varying certain attributes of just a single input signal. Two examples are: a) A group of violins, composed of several signals that have been generated as variations of just one violin recording, using individually randomized Chorus, Spectrum and amplitude effects. b) A number of speech signals with a given output length, created by performing randomized pitch change, tempo shift and random amplitude modulation. The length of the output speech signal can be obtained by time shifting and repeating each of the processed signals with pauses of random length in-between until the desired total length is obtained.

The use of sine sweeps is a robust method to measure room impulse responses. One particular advan... more The use of sine sweeps is a robust method to measure room impulse responses. One particular advantage is that the frequency spectrum of the excitation signal can be controlled in the time domain-by changing the rate of frequency change-while keeping the amplitude of the signal virtually constant over time. The sine sweep approach is adopted in the measurement tool of the ODEON software. In this paper, a method to optimize the measurements is introduced. The spectrum of the sweep signal is modified, making use of a previously measured impulse response and its resulting Schroeder decay curve. The maximum dynamic range of the Schroeder curve is defined as the decay range. This decay range is calculated in octave bands, and its deviation from a broadband average is subtracted from the sweep spectrum magnitude. The goal of this approach is to redistribute the power across frequency bands in order to ensure a more uniform signal-to-noise ratio (SNR). The method is evaluated through experimental measurements. The proposed optimization leads to a more constant decay range across octave bands, with an improved SNR in bands with poor decay. Practical aspects including repeatability and sweep duration are discussed.

A new method has been developed for the calculation of transmission through walls, including aura... more A new method has been developed for the calculation of transmission through walls, including auralization in the receiving room. This has been made as an option in the room acoustic simulation software Odeon version 9. Transmission through multiple walls can be investigated; even walls with different materials on either side and with thickness can be handled. The influence of partial areas with different transmission losses, the volumes of the rooms, and the reverberation times of the rooms are included in the simulation results.

The Journal of the Acoustical Society of America, 1996

Original contributions to the Technical Notes and Research Briefs section are always welcome. Man... more Original contributions to the Technical Notes and Research Briefs section are always welcome. Manuscripts should be double-spaced, and ordinarily not longer than about 1500 words. There are no publication charges, and consequently, no free reprints; however, reprints may be purchased at the usual prices. Error in the calculation of synchronized spontaneous otoacoustic emission frequencies measured with the ILO88 system [43.64.Jb, 43.64.Yp]

The Journal of the Acoustical Society of America, 2005

and it is a condition of accessing publications that users recognise and abide by the legal requi... more and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

The Journal of the Acoustical Society of America, 2008

Geometric computer models for room acoustics, such as ODEON, predict sound fields most reliably a... more Geometric computer models for room acoustics, such as ODEON, predict sound fields most reliably at high frequencies. At low frequencies, algorithms must be modified to account for deviations from geometrical acoustics caused by wave phenomena. For finite reflectors, a common low frequency model is based on the Kirchhoff-Fresnel Diffraction Approximation, which predicts a uniform 6 dB per octave slope below a reflector's geometrical limiting frequency. As discussed in this paper, highly accurate Boundary Element Method simulations, not subject to the Kirchhoff Approximation, suggest the use of an additional, lower limiting frequency and slope of 12 dB per octave to represent the reflector's response at the lowest frequencies. This second limiting frequency and 12 dB per octave slope, referred to as the dipole limiting frequency, are presented in a form suitable for insertion into a geometric computer model. [Work supported by the National Science Foundation.]

Acta Acustica united with Acustica, 2008

This thesis represents a method for reducing the geometry of complex room models to make it possi... more This thesis represents a method for reducing the geometry of complex room models to make it possible to model their acoustics in real-time. It is shown that reducing geometry can vastly decrease the modeling time. This conclusion is supported by the experimental results. The previous work on geometric model simplification is surveyed extensively. The reduction algorithms are grouped into decimation algorithms and surface reconstruction algorithms. The decimation algorithms are categorized into vertex removal, vertex clustering, edge collapsing, and triangle removal algorithms. The surface reconstruction algorithms include re-meshing and volumetric approaches. The main contribution of this thesis is a method for reducing geometric models for acoustics modeling. It consists of two steps: topology simplification and geometry reduction. Two approaches are suggested for the topology simplification, one based on a regular density grid and another based on an octree. There are also two algorithms for the geometry reduction both of which are trying to merge small coplanar triangles into large polygons. The results of the reduction method are evaluated using the acoustical parameters. Also the performance of the reduction algorithm is analyzed. The experiments show that the algorithm preserves spatial properties, measured by the reverberation time, relatively well. The algorithm can produce coarsest level approximations in real-time, but more accurate approximations require significantly longer times for computation.

The correct level of presentation is important for all kinds of auralisation in order to be as re... more The correct level of presentation is important for all kinds of auralisation in order to be as realistic as possible. The method applied in ODEON is approximate, aiming at the A-weighted sound pressure level to match that of the calculation result of the same simulation. A pink noise signal is applied for the calibration. The trick is to create modified versions of the input signals used for auralisation in such a way that the input signals have the same A-weighted level. In order to ensure a proper calibration it is necessary to know the sound power level of the sound source used as input for the auralisation. This can be difficult in some cases and may be the major source of uncertainty in the calibration. Next step is to look at the room simulation that produces the auralisation, and to choose a source-receiver combination to be used for the calibration. The relation between the sound power of the source and the sound pressure level in the receiver position is a result of the roo...

The Roman theatre follows a natural evolution from the Greek theatre combining the acting area an... more The Roman theatre follows a natural evolution from the Greek theatre combining the acting area and the seating area into a single structure. Modifications of stage, orchestra and seating area have resulted in a considerable improvement in the quality of the acoustics. As a part of the ERATO project, the acoustics in Roman theatres and Odea (roofed theatres) have been recreated through computer simulations using the Odeon software. Computer models of five Roman theatres have been created based on data from archaeologists, architects and measurements in situ. The theatres have been modelled in their present state and as they presumably were built in the Roman era; the reconstructed parts of acoustical interest are the stage wall and top colonnade in the open-air theatres and the roof and windows in the Odea. The irregular absorption distribution in these rooms makes them challenging for acoustical simulations differing from traditional concert halls. Auralisation examples will be pres...

This paper presents an extension to the traditional room acoustic modelling methods allowing comp... more This paper presents an extension to the traditional room acoustic modelling methods allowing computer modelling of huge machinery in industrial spaces. The program in question is Odeon 3.0 Industrial and Odeon 3.0 Combined which allows the modelling of point sources, surface sources and line sources. Combining these three source types it is possible to model huge machinery in an easy and visually clear way. Traditionally room acoustic simulations have been aimed at auditorium acoustics. The aim of the simulations has been to model the room acoustic measuring setup consisting of an omnidirectional sound source and a microphone. This allows the comparison of simulated results with the ones measured in real rooms. However when simulating the acoustic environment in industrial rooms, the sound sources are often far from being point like, as they can be distributed over a large space in the room and may indeed contribute surfaces to the room. Examples of such sources could be ventilation...

Multi-channel orchestral anechoic recordings were obtained at the Technical University of Denmark... more Multi-channel orchestral anechoic recordings were obtained at the Technical University of Denmark (DTU) in June 2005. Every orchestral part of specific movements of two symphonies, Brahms’ Symphony No. 4, 3 rd movement, and Mozart’s Symphony No. 40 in g minor, 1 st movement, were digitally recorded using five 0.5” DPA microphones, with four surrounding the musicians in the horizontal plane and the fifth directly above. The recordings were made in DTU’s large anechoic chamber, which has free space of about 1000 m 3 and a lower frequency limit of 50 Hz. Each musician was recorded individually, and to assist with overall synchronization of all recordings, the musicians listened to the piece over headphones and viewed a video of a conductor while playing. In general, for the string parts, two to three individual musicians were recorded, and only one instrumentalist was recorded for the remaining brass, woodwind, and percussion parts. These recordings have been edited for use in room aco...

which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer mo... more which are ignored by classical geometrical acoustics. ODEON, a well-known geometrical computer model, is in the process of upgrading its ray tracing and scattering algorithm. The new algorithm allows users to specify transmission through reflector panel arrays. To aid in the development of ODEON’s new algorithm, its predictions are compared with predictions from a boundary element method (BEM) model. The computationally intense BEM model is shown to be very accurate in predicting the response from single- and multi-panel reflector arrays. Comparisons will be shown for several reflector arrays of varied size and density. The BEM results have been filtered into octave bands for ease of comparison.

The measured impulse response is often used as a true reference of a real room impulse response a... more The measured impulse response is often used as a true reference of a real room impulse response and geometrical acoustic simulations are considered to be only a crude representation of it. However, both approaches have their own challenges and limitations. Geometrical acoustic models do not include wave phenomena, such as interferences and diffraction, as they simplify sound propagation by rays. The advantages of acoustic simulations with such models include a perfectly omnidirectional and impulsive sound source, no distortion problems, full control of the background noise, and a well-defined onset time of the impulse response. On the other hand, impulse response measurements include wave phenomena, but they do have their own weaknesses, which may cause significant errors in the derivation of the ISO-3382 room acoustic parameters. Due to the presence of background noise in the measured impulse response it is difficult to evaluate which part is valid. In addition, the sound source us...

The measurement of the Sound Strength (G) room acoustic parameter requires a calibration of the m... more The measurement of the Sound Strength (G) room acoustic parameter requires a calibration of the measuring system, so either the sound power of the source or the sound pressure level at a distance of 10 m in free field is known. Two procedures are described in ISO 3382-1: Calibration in a reverberation chamber and calibration in free field in a large anechoic chamber. Both methods require that all conditions in the measuring chain (amplification gains, sound card, cables etc.) remain fixed during calibration and in-situ measurements. This can be impractical mainly because measurements may be performed much later than calibration and at a distant location, and it cannot be guaranteed that the conditions in the measuring chain remain unchanged. In this paper a Two-step calibration procedure is proposed that removes the requirement of fixed conditions of the measuring chain. The procedure adds a second step to the normal reverberation room or free field calibration methods, in order to ...

The application of room acoustic simulations to industrial halls with a large number of sound sou... more The application of room acoustic simulations to industrial halls with a large number of sound sources has been known for many years as an efficient means for noise control. However, the application of the auralisation tool to multi-source environments is rather new. The challenges and possibilities are discussed through a number of examples including a symphony orchestra in a concert hall, crowd sounds in a theatre, and the speech privacy in an open plan office. In order to make this technique a useful tool it is important that the quality and realism of the auralisation is very high, but also that the user interface allows a sufficient overview and control of the whole scenario. Good localisation is particularly important in multi-source environments. For some applications the use of headphones is not possible, so it is necessary that the auralisation can be presented through a surround loudspeaker system.

The use of computer models for acoustical design of auditoria takes advantage of visualization an... more The use of computer models for acoustical design of auditoria takes advantage of visualization and auralization for several purposes, some of which will be presented. The sound absorption characteristics of materials can be visualized by the use of colors of surfaces in a 3D room model. Calculation results displayed as color maps in a grid can give a quick overview of complicated conditions of sound distribution, including the display of acoustical parameters for noise level, sound strength, clarity, echo etc. The dynamic picture of a wave front with thousands of balls emitted from a source and reflected in a room has proven to be a useful tool to understand complicated conditions of sound reflection. Using auralization dynamic phenomena like reverberance, echo, and flutter echo can be auralized by listening to a hand clap. Coloration is another phenomenon that may be auralized by listening to white noise. The multisource auralization of a symphony orchestra where each single instru...