A method of simulating a room impression and/or sound impression occurring at a representative listening location in a room with monophonic, stereophonic or multichannel reproduction includes selecting a room whose sound is to be simulated. A location of a representative listening location is then determined. Subsequently, the corresponding room impulse response at least for one channel is determined at the representative listening location. A threshold value which exceeds over at least a portion of the duration of the determined room impulse response is determined for the determined room impulse response. By comparing the determined room impulse response with the threshold value, a reduced room impulse response is produced which within the portion of the duration of the determined room impulse response only includes those contents of the determined room impulse response in which a momentary amplitude is above the threshold value. The reduced impulse response to the value zero for those contents of the determined room impulse response whose momentary amplitude is below the threshold value is set. Outside of the portion of the duration of the determined room impulse response, the reduced room impulse response contains the determined room impulse response in unchanged form.
A method for the creation of acoustic impulse responses for utilization in rendering to an array of speakers comprising the steps of measuring a room response function; extracting a series of discrete time arrivals from the measured room response function so as to have a reverberant residual response function; separately rendering the extracted series and the reverberant residual response function to the array of speakers to form a discrete response and a residual response; combining the discrete response and the residual response to form an acoustic impulse response for the array of speakers.
A method of processing a series of input audio signals representing a series of virtual audio sound sources placed at predetermined positions around a listener to produce a reduced set of audio output signals for playback over speaker devices placed around a listener, the method comprising the steps of: (a) for each of the input audio signals and for each of the audio output signals: (i) convolving the input audio signals with an initial head portion of a corresponding impulse response mapping substantially the initial sound and early reflections for an impulse response of a corresponding virtual audio source to a corresponding speaker device so as to form a series of initial responses; (b) for each of the input audio signals and for each of the audio output signals: (i) forming a combined mix from the audio input signals; and (ii) forming a combined convolution tail from the tails of the corresponding impulse responses; (iii) convolving the combined mix with the combined convolution tail to form a combined tail response; (c)for each of the audio output signals: (i) combining a corresponding series of initial responses and a corresponding combined tail response to form the audio output signal.
The invention provides a method and system for forming an output impulse response function. The method includes the steps of creating an initial impulse response, and dividing the impulse response into a head portion and a tail portion. The tail portion is high pass filtered, and low frequency components of the head portion are boosted. The low frequency boosted and high pass filtered respective head and tail portions are then combined into a modified output impulse response, which can then be used to spatialize an audio signal by convolving it.
A method and apparatus for locating the user of a computer system and adjusting the sound from the system speakers. The computer system includes a computer, two speakers, a microphone, a signal processor, and an audio processor. The speakers emit a sound which is reflected from the user and other objects in the vicinity of the system. The invention includes an algorithm for determining which of the reflected sounds had been reflected from the user of the computer system. The character of the sound emitted by the computer system is then adjusted to enhance the sound effects at the location of the user.
The method is provided for simulating an audio effect processor. At least two impulse responses are stored representing the audio processor for input signals having different characteristics. The same characteristic of the input signal is then repeatedly assessed and at least one of the impulse responses selected to apply to the input signal in dependence on the result of the assessment. The selected impulse response is then applied to the input signal to derive an output signal. This process continues throughout the duration of the input signal, thereby taking account of time dependent changes in the assessed characteristics.
