This disclosure relates to systems and methods for sound system design and simulation. As used herein, design system and simulation system are used interchangeably and refer to systems that allow a user to build a model of at least a portion of a venue, arrange sound system components around or within the venue, and calculate one or more measures characterizing an audio signal generated by the sound system components. The design system or simulation system may also simulate the audio signal generated by the sound system components thereby allowing the user to hear the audio simulation.
A sound system design/simulation system includes background noise to provide more realistic sound renderings of the designed space and more accurate quality measures of the design space. The background noise may be provided as a library in the design system that allows the user to select a background noise profile. The user may also provide a recording of a background noise from the built space or from a similar space. The design system converts the recorded background noise to a background noise profile and adds the profile to the library of background noise profiles. The user can select a background noise profile and associate the profile with a specified space. The user can adjust the noise level of the background noise and the design system automatically updates one or more quality measures in response to the change in background noise level.
One embodiment of the present invention is directed to an audio simulation system comprising: a model manager configured to enable a user to build a 3-dimensional model of a venue and place and aim one or more loudspeakers in the model; an audio engine configured to estimate a coverage pattern in a portion of the venue based on at least one acoustic characteristic of a component of the model; and an audio player generating at least two acoustic signals simulating an audio program played over the one or more loudspeakers in the model, each of the at least two acoustic signals including an audio program signal and a background noise signal. In one aspect, the background noise signal is equalized to reduce linear distortions introduced by the audio player. Another aspect further comprises a background noise library, the library including at least one user-defined background noise file, the user-defined background noise file including a noise profile portion and a background noise signal representing acoustic signal of the background noise, the noise profile portion used by the audio engine to estimate a speech intelligibility coverage pattern, the background noise signal played by the audio player simulating a background noise. In a further aspect, the background noise signal is recorded at the venue modeled by the simulation system. In a further aspect, the background noise signal is recorded at a venue similar to the venue modeled by the simulation system. In a further aspect, a level of the background noise signal is adjusted independently of the level of the audio program signal. In a further aspect, the speech intelligibility coverage pattern is automatically updated to reflect the independently adjusted background noise signal relative to the audio program signal. Another aspect further comprises a profile editor configured to allow a user to graphically edit the noise profile portion of the user-defined background noise file.
Another embodiment of the present invention is directed to an audio simulation method comprising: providing an audio simulation system including a model manager, an audio engine, and an audio player; building a model of a venue in the audio simulation system, the model including a sound system; selecting a location in the model; and generating at least two acoustic signals simulating an audio program played over the sound system in the model at the selected location, each of the at least two acoustic signals including an audio program signal and a background noise signal. Another aspect further comprises selecting the background noise signal based on the venue. Another aspect further comprises adjusting the background noise signal independently of the audio program signal. Another aspect further comprises recording a background noise at an existing venue; equalizing the recorded background noise to reduce linear distortions introduced by the audio player; and saving the equalized background noise in a file, the file part of a library of background noise files selectable by the user. Another aspect further comprises editing the background noise signal.
Another embodiment of the present invention is directed to a computer-readable medium storing computer-executable instructions for performing a method comprising: providing an audio simulation system including a model manager, an audio engine, and an audio player; building a model of a venue in the audio simulation system, the model including a sound system; selecting a location in the model; and generating at least two acoustic signals simulating an audio program played over the sound system in the model at the selected location, each of the at least two acoustic signals including an audio program signal and a background noise signal.
a illustrates a detailed view of the data window with an MTF tab selected.
b displays exemplar MTF plots indicative of typical speech intelligibility problems.
The audio engine 130 estimates one or more sound qualities or sound measures of the venue based on the acoustic model of the venue managed by the model manager 120 and the placement of the audio components. The audio engine 130 may estimate the direct and/or indirect sound field coverage at any location in the venue and may generate one or more sound measures characterizing the modeled venue using methods and measures known in the acoustic arts.
The audio player 140 generates at least two acoustic signals that preferably give the user a realistic simulation of the designed sound system in the actual venue. The user may select an audio program that the audio player uses as a source input for generating the at least two acoustic signals that simulate what a listener in the venue would hear. The at least two acoustic signals may be generated by the audio player by filtering the selected audio program according to the predicted direct and reverberant characteristics of the modeled venue predicted by the audio engine. The audio player 140 allows the designer to hear how an audio program would sound in the venue, preferably before construction of the venue begins. In many instances, the human ear may be able to distinguish small and subtle differences in the sound field that may not be apparent in the sound field coverage maps generated by the audio engine 130. This allows the designer to make changes to the selection of materials and/or surfaces during the initial design phase of the venue where changes can be implemented at low cost relative to the cost of retrofitting these same changes after construction of the venue. The auralization of the modeled venue provided by the audio player also enables the client and designer to hear the effects of different sound systems in the venue and allows the client to justify, for example, a more expensive sound system when there is an audible difference between sound systems. An example of an audio player is described in U.S. Pat. No. 5,812,676 issued Sep. 22, 1998, herein incorporated by reference in its entirety.
Examples of interactive sound system design systems are described in co-pending U.S. patent application Ser. No. 10/964,421 filed Oct. 13, 2004, herein incorporated by reference in its entirety. Procedures and methods used by the audio engine to calculate coverage, speech intelligibility, etc., may be found in, for example, K. Jacob et al., “Accurate Prediction of Speech Intelligibility without the Use of In-Room Measurements,” J. Audio Eng. Soc., Vol. 39, No. 4, pp. 232-242 (April, 1991) and are herein incorporated by reference in their entirety. Auralization methods implemented by the audio player may be found in, for example, M. Kleiner et al., “Auralization: Experiments in Acoustical CAD,” Audio Engineering Society Preprint # 2990, September, 1990 and is herein incorporated by reference in its entirety.
The modeling window 220, detail window 230, and the data window 240 simultaneously present different aspects of the design project to the user and are linked such that data changed in one window is automatically reflected in changes in the other windows. Each window can display different views characterizing an aspect of the project. The user can select a specific view by selecting a tab control associated with the specific view.
The Direct, Direct+Reverb, and Speech tabs estimate and display coverage patterns for the direct field, the direct+reverb field, and a speech intelligibility field. The coverage area may be selected by the user. The coverage patterns are preferably overlaid over a portion of the displayed model. The coverage patterns may be color-coded to indicate high and low areas of coverage or the uniformity of coverage. The direct field is estimated based on the SPL at a location generated by the direct signal from each of the speakers in the modeled venue. The direct+reverb field is estimated based on the SPL at a location generated by both the direct signal and the reflected signals from each of the speakers in the modeled venue. A statistical model of reverberation may be used to model the higher order reflections and may be incorporated into the estimated direct+reverb field. The speech intelligibility field displays the speech transmission index (STI) over the portion of the displayed model. The STI is described in K. D. Jacob et al., “Accurate Prediction of Speech Intelligibility without the Use of In-Room Measurements,” J. Audio Eng. Soc., Vol. 39, No. 4, pp 232-242 (April, 1991), Houtgast, T. and Steeneken, H. J. M. “Evaluation of Speech Transmission Channels by Using Artificial Signals” Acoustica, Vol. 25, pp 355-367 (1971), “Predicting Speech Intelligibility in Rooms from the Modulation Transfer Function. I. General Room Acoustics,” Acoustica, Vol. 46, pp 60-72 (1980) and the international standard “Sound System Equipment—Part 16: Objective Rating of Speech Intelligibility by Speech Transmission Index, IEC 60268-16, which are each incorporated herein in their entirety.
When the Simulation tab is selected, the detail window display one or more input controls that allow the user to specify a value or select from a list of values for a simulation parameter. Examples of simulation parameter include a frequency or frequency range encompassed by the coverage map, a resolution characterizing the granularity of the coverage map, and a bandwidth displayed in the coverage map. The user may also specify one or more surfaces in the model for display of the acoustic prediction data.
The Surfaces, Loudspeakers, and Listeners tab allows the user to view the properties of the surfaces, loudspeakers, and listeners, respectively, placed in the model and allows the user to quickly change one or more parameters characterizing a surface, loudspeaker or listener. The Properties tab allows the user to quickly view, edit, and modify a parameter characterizing an element such as a surface or loudspeaker in the model. A user may select an element in the modeling window and have the parameter values associated with that element displayed in the detail window. Changes made by the user in the detail window are reflected in an updated coverage map, for example, in the modeling window.
When selected, the EQ tab enables the user to specify an equalization curve for one or more selected loudspeakers. Each loudspeaker may have a different equalization curve assigned to the loudspeaker.
In
A user may select a pin shown in
The user can select the proper delays by displaying in the data window the direct arrivals in the time response plot. The user can select a pin representing one of the direct arrivals to identify the source of the selected direct arrival in the modeling window, which displays the path of the selected direct arrival from one of the loudspeakers in the model. The user can then adjust the delay of the identified loudspeaker in the detail window such than the first direct arrival the listener hears is from the loudspeaker closest to the audio source.
The concurrent display of both the model and coverage field in the modeling window, a response characteristic such as time response in the data window, and a property characteristic such as loudspeaker parameters in the detail window enables the user to quickly identify a potential problem, try various fixes, see the result of these fixes, and select the desired fix.
Removing objectionable time arrivals is another example where the concurrent display of the model, response, and property characteristics enables the user to quickly identify and correct a potential problem. Generally, arrivals that arrive more than 100 ms after the direct arrival and are more than 10 dB above the reverberant field may be noticed by the listener and may be unpleasant to the listener. The user can select an objectionable time arrival from the time response plot in the data window and see the path in the modeling window to identify the loudspeaker and surfaces associated with the selected path. The user can select one of the surfaces associated with the selected path and modify or change the material associated with the selected surface in the detail window and see the effect in the data window. The user may re-orient the loudspeaker by selecting the loudspeaker tab in the detail window and entering the changes in the detail window or the user may move the loudspeaker to a new location by dragging and dropping the loudspeaker in the modeling window.
a shows the data window with the MTF tab 626 selected. The Modulation Transfer Function (MTF) returns a normalized modulation preserved as a function of modulation frequency for a given octave band. A discussion of the MTF is presented in K. D. Jacob, “Development of a New Algorithm for Predicting the Speech Intelligibility of Sound Systems,” presented at the 83rd Convention of the Audio Engineering Society, New York, N.Y. (1987), Houtgast, T. and Steeneken, H. J. M. “Evaluation of Speech Transmission Channels by Using Artificial Signals” Acoustica, Vol. 25, pp 355-367 (1971) and “Predicting Speech Intelligibility in Rooms from the Modulation Transfer Function. I. General Room Acoustics,” Acoustica, Vol. 46, pp 60-72 (1980), and the international standard “Sound System Equipment—Part 16: Objective Rating of Speech Intelligibility by Speech Transmission Index, IEC 60268-16, which are each incorporated herein in their entirety. In
b displays exemplar MTF plots that may indicate the source of a speech intelligibility problem. In
As
In addition to selecting a background noise profile from a library of standard noise profiles, the user may create or import a new background noise profile. The ability to create or import a new background noise profile may provide for a more realistic audio rendering by the audio player of the design model. If the design project involves a venue that is already built, the user can provide a background noise profile that was generated from a recording in the existing venue. If the design project involves a venue that has not completed construction, the user may record background noise at a similar venue, such as for example, an airport or train station that can provide a more realistic rendering to the user. In another example, a recording may be made of the “babble” generated by the conversations at adjacent tables in a restaurant to simulate a more realistic restaurant environment. Each background noise profile may be stored as a separate file by the design system.
In addition to seeing the effect of the background noise on the coverage map, the user can also hear the effect through the audio playback device. By playing an appropriate background noise through the audio player along with the program signal, the user experiences a more realistic simulation of the model. For example, if the model is of a check-in area of an airport, a background noise profile generated from a recording of a check-in area of an airport would provide a more realistic simulation than, for example, a standard pink noise profile. The user may record background noise at a similar venue if the modeled venue has not been built and process the recorded background noise into a format compatible with the simulation system. For example, the recorded background noise may be transformed into the frequency domain to generate the noise profile for the recorded background noise. The recorded background noise may be filtered and stored in a format compatible with the audio player. The filtering of the recorded background noise equalizes the recorded signal to compensate for any linear distortions introduced by the audio player. For example, the audio player may add 10 dB above 10 kHz and to compensate for the 10 dB boost, the recorded signal is equalized to reduce the signal by 10 dB above 10 kHz such that the rendered audio playback reduces linear distortions introduced by the audio player. The generated profile and filtered recording are stored in the background noise library. When the user selects the noise profile, both the noise profile and filtered recording are loaded into the model. The noise profile is used to calculate, for example, the STI coverage. The filtered recording is played through the audio player when selected by the user.
Embodiments of the systems and methods described above comprise computer components and computer-implemented steps that will be apparent to those skilled in the art. For example, it should be understood by one of skill in the art that portions of the audio engine, model manager, user interface, and audio player may be implemented as computer-implemented steps stored as computer-executable instructions on a computer-readable medium such as, for example, floppy disks, hard disks, optical disks, Flash ROMS, nonvolatile ROM, flash drives, and RAM. Furthermore, it should be understood by one of skill in the art that the computer-executable instructions may be executed on a variety of processors such as, for example, microprocessors, digital signal processors, gate arrays, etc. For ease of exposition, not every step or element of the systems and methods described above is described herein as part of a computer system, but those skilled in the art will recognize that each step or element may have a corresponding computer system or software component. Such computer system and/or software components are therefore enabled by describing their corresponding steps or elements (that is, their functionality), and are within the scope of the present invention.
Having thus described at least illustrative embodiments of the invention, various modifications and improvements will readily occur to those skilled in the art and are intended to be within the scope of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto.