Applications of a system for two-channel auralization using ODEON-SOUND (original) (raw)

Auralisation of a Symphony Orchestra With Odeon - the Chain From Musical Instruments to the Eardrums

Auralisation is a very complicated technique, the quality of which depends on every single part in a long chain, starting with the anechoic recording of the sound to be used as input, continu- ing through the room acoustic simulation that connects the source and the receiver, and ending in the presentation of the sound to the listening person. The auralisation of a symphony orchestra is an even bigger challenge because of the large number of sound sources distrib- uted over a considerable area. Recently, a number of high quality anechoic recordings of symphonic music aiming at the multi- source auralisation technique have been available. So, the aim of this paper is to give an overview of the auralisation chain with particular reference to the multi-source auralisation of a sym- phony orchestra.

Subjective Assessment of the Multi-Channel Auralizations

Acta Physica Polonica A, 2012

The article presents the course and the results of an experiment, which aimed at the subjective assessment of the multi-channel impulse responses. The assessment was conducted considering the usefulness of the received responses for the conducting operation of the digital convolution. The resulting sound material is generated for the simulation of the characteristics of the room. In a medium-sized, rectangular reverberation room (74 m 3) a number of measurements of impulse responses were conducted with the use of multi-channel microphone techniques and with the use of SoundField type microphone. In identical conditions the raw sound material was recorded (in conditions of free eld). Next, the convolution was performed between the raw material and the recorded impulse responses. The group of experts, whose members had at least 5 years of experience in the eld of sound engineering, was subjected to the psychoacoustic tests aiming at comparison of the sound materials achieved in the convolution and in the recording.

Synchronization of spontaneous otoacoustic emissions to a 2f1−f2 distortion product

The Journal of the Acoustical Society of America, 1990

Amplitude and frequency fluctuations of spontaneous otoacoustic emissions have been studied. Spontaneous otoacoustic emissions were recorded from eight human ears and two frog ears (Rana esculenta). Record length typically was 80 s. For a recorded emission signal, the amplitude signal .4 (t) (average.40) and time intervals T(ti) between successive positive-going zero crossings (i counts zero crossings) were determined. Emission amplitude and period both showed small fluctuations: 3.4•,•/.4o ranged from 0.7 X 10 -• to 6.3 X 10-2 for human emissions and was 24 X 10 -2 for both frog emissions; •T•ms ranged from 1.4 to 6.9 X 10 -? s for human emission and was 50.0 and 55.0)< 10-? s for the two frog emissions. There was a positive correlation between •.4•m•/.40 and 3Tr•s as determined for different emissions (R = 0.9). Spectra of A (t) and T( ti ) revealed that amplitude and period were slowly fluctuating functions: cutoff frequency Af• of the amplitude spectrum ranged from 3 to 18 Hz; Afar ranged from 7 to 32 Hz. Results have been compared to amplitude and frequency fluctuations era second-order oscillator, that interacts With a noise source. It has been concluded that an oscillator with linear stiffness (for example a Van der Pol oscillator) driven by white Gaussian noise, cannot account for all experimental results. Other possible oscillators (e.g., nonlinear stiffness) and noise sources (e.g., narrow-band noise), that may account for the observed phenomena, are discussed. PACS numbers: 43.64Jb, 43.64.Bt INTRODUCTION Spontaneous otoacoustic emissions (SOAE) are narrow-band acoustic signals ( Kemp, 1979; Zurek, 1981; Palmer and Wilson, 1981 ). They have been recorded in quantity from human (Dallmayr, 1985; Strickland et al., 1985; Rebillard etaL, 1987) and frog ears (Wilson etaL, 1986; van Dijk et al., 1989). Many hearing researchers consider the existence of SOAEs as important evidence for the hypothesis that the inner ear makes use of active signal filtering, in order to optimize its performance as signal detector (Dallos, 1988). Under certain conditions, an active filter can become unstable, which results in oscillation. Instability of an active filter in the inner ear, would generate a certain amount of acoustical energy, being radiated out into the ear canal (Gold, 1948). Thus, SOAEs are possibly a byproduct of active signal processing in the inner ear.

Interactions Among Multiple Spontaneous Otoacoustic Emissions

Lecture Notes in Biomathematics, 1986

Evidence has recently been obtained for several interact ions among spontaneous otoacoustic emissions (SOAEs) including intermodulation distortion products, mutual suppression, and noncontiguous-linked SOAEs which ap parently share energy between two quasi-stable states. In this paper, we give an updated record of our findings on intermodulation distortion products and linked emissions, and give evidence that the former tend to occur when a distortion product frequency is close to that of a cochlear resonance. Computer simulations of the interactions among van der Pol oscillators, which represent nonlinear active elements in a simplified cochlear model, appear to qualitatively account for some of the observed features of SOAE interactions.

Otoacoustic emissions of the 4th kind: Nonlinear reflection

Acoustical Science and Technology

Otoacoustic emission (OAE) refers to acoustic waves that originate from the cochlea. Since its discovery, various ways have been developed to elicit OAEs; those elicited by short clicks are called transient-evoked (TE) OAEs, and the cubic distortion elicited by two tones are called distortionproduct (DP) OAEs. In addition, spontaneous OAEs can be found from some ears without applying any external stimulus. Shera and Guinan proposed a taxonomy of OAEs that consists of three kinds: the linearly reflected emissions, the spontaneous emissions, and the distortion emissions. This article aims to introduce an additional 4th kind of OAEs to the taxonomy. We have shown theoretically that, when a high frequency, large-amplitude suppressor tone is present, it may set up a temporary and reversible impedance mismatch for the traveling waves that pass through its characteristic place. Because of this mismatch, the waves get partially reflected and going backward toward the stapes. The derivation of this ''nonlinear reflection'' mechanism is based on de Boer's quasi-linear, equivalent system framework, and may help explain the controversial tone-burst evoked OAEs experiments obtained in recent years.

Validation of an auralization system

The Journal of the Acoustical Society of America, 2002

The room acoustics program ODEON provides auralization using fully filtered binaural room impulse responses, each reflection being filtered through nine octave bands and a set of head-related transfer functions. Using the full filtering scheme allows, in principle, a complete audible presentation of all the properties, time-variant frequency coloration, as well as directional information predicted by the room acoustics program. Two methods of verification have been applied. The first method is based on direct measurements on the impulse responses predicted by ODEON, using the room acoustics measuring system DIRAC in order to verify that the auralization method is actually capable of reproducing the predicted room acoustic parameters. Monaural auralization filters were used for this purpose. The other method is an audible comparison between in situ recordings of a singing person in real rooms and the ODEON auralization of the same situations. The latter verification is part of an ongoing European research project, CAHRISMA, on restoration of the acoustics in old Byzantine churches and mosques in Istanbul. 8:30 3aAAa2. Effect of model detail level on room acoustic computer simulations. David T. Bradley and Lily M. Wang ͑Univ. of Nebraska-Lincoln, Peter Kiewit Inst., 1110 S. 67th St., Omaha, NE 68182-0681, dbradley@mail.unomaha.edu͒