Efficient Phantom Source Widening

Zotter, Franz; Frank, Matthias

doi:10.2478/aoa-2013-0004

Cited by 15 publications

(18 citation statements)

References 9 publications

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“…An introduction of differences between horizontal channel signals leads to a change in the relationship between ear input signals. For example, a lower interchannel cross-correlation coefficient (ICCC) tends to produce a lower interaural cross-correlation coefficient (IACC), thus causing the perception of a wider auditory image [3].…”

Section: Introductionmentioning

confidence: 99%

“…Various methods have been proposed for rendering auditory image spread in horizontal stereo, such as decorrelation techniques based on all-pass filtering [1][2][3] and comb-filtering [4], stereo shuffling [5], and frequencydependent panning [6]. These methods are fundamentally based on the fact that our ears are spaced apart and horizontally arranged.…”

Section: Introductionmentioning

confidence: 99%

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Perceptual Band Allocation (PBA) for the Rendering of Vertical Image Spread with a Vertical 2D Loudspeaker Array

Lee

2016

J. Audio Eng. Soc.

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Two subjective experiments were conducted to examine a new vertical image rendering method named "Perceptual Band Allocation (PBA)," using octave bands of pink noise presented from main and height loudspeaker pairs. The PBA attempts to control the perceived degree of vertical image spread (VIS) by a flexible mapping between frequency band and loudspeaker layer based on the desired positioning of the band in the vertical plane. The first experiment measured the perceived vertical location of the phantom image of each octave band stimulus for the main and height loudspeaker layers individually. Results showed significant differences among the frequency bands in perceived image location. Furthermore, the so-called "pitch-height" effect was found for two separate frequency regions, with most bands from the main loudspeaker layer perceived to be elevated from the physical height of the layer. Based on the localization data from the first experiment, six different PBA stimuli were created in such a way that each frequency band was mapped to either the main or height loudspeaker layer depending on the target degree of VIS. The second experiment conducted a listening test to grade the perceived magnitudes of VIS for the six stimuli. The results first indicated that PBA could significantly increase the perceived magnitude of VIS compared to that of a sound presented only from the main layer. It was also found that the different PBA schemes produced various degrees of perceived VIS with statistically significant differences. The paper discusses possible reasons for the obtained results in details based on the localization test results and the frequency-dependent energy weightings of ear-input signals. Implications of the proposed method for the vertical upmixing of horizontal surround content are also discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Perceptual Band Allocation (PBA) for the Rendering of Vertical Image Spread with a Vertical 2D Loudspeaker Array

Lee

2016

J. Audio Eng. Soc.

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“…Therefore, a new method that can render vertical image spread would be necessary. In the context of horizontal stereophony, horizontal image spread can be rendered by means of interchannel decorrelation, and many different decorrelation methods have been proposed over the past years [6][7][8][9][10]. Such methods are based on the principle that as the degree of correlation between stereophonic channel signals decreases, that between ear-input signals (interaural crosscorrelation), which has a direct relationship with perceived auditory image spread [4], also decreases.…”

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confidence: 99%

2D-to-3D Ambience Upmixing based on Perceptual Band Allocation

Lee

2015

J. Audio Eng. Soc.

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Listening tests were conducted to evaluate the feasibility of a novel 2D-to-3D ambience upmixing technique named "perceptual band allocation" (PBA). Four-channel ambience signals captured in a reverberant concert hall were low-pass and high-pass filtered, which were then routed to lower and upper loudspeaker layers arranged in a 9-channel 3D configuration, respectively. The upmixed stimuli were compared against original 3D recordings made using an 8-channel ambience microphone array in terms of 3D listener envelopment and preference. The results suggest that the perceived quality of the proposed method could be at least comparable to that of an original 3D recording. INTRODUCTIONThree-dimensional multichannel audio systems such as Auro-3D [1], Dolby Atmos [2], and 22.2 [3] employ additional height loudspeakers in order to provide the listener with a three-dimensional (3D) auditory experience. One of the perceptual attributes that could be enhanced by the use of height channels is listener envelopment (LEV). In the context of two-dimensional (2D) surround sound (e.g., 5.1), LEV is widely understood as the subjective impression of being enveloped by reverberant sound [4,5]. With 3D loudspeaker formats, the added height channels could be used to render the "vertical" spread of reverberant sound image as well as the horizontal one, and ultimately the auditory impression of 3D LEV could be achieved.One of the key requirements for 3D multichannel audio applications would be a 2D-to-3D upmixing technique that can add a height dimension to 2D content. Therefore, a new method that can render vertical image spread would be necessary. In the context of horizontal stereophony, horizontal image spread can be rendered by means of interchannel decorrelation, and many different decorrelation methods have been proposed over the past years [6][7][8][9][10]. Such methods are based on the principle that as the degree of correlation between stereophonic channel signals decreases, that between ear-input signals (interaural crosscorrelation), which has a direct relationship with perceived auditory image spread [4], also decreases. However, vertically reproduced stereophonic signals would have no or little influence on interaural cross-correlation. From a recent study by Gribben and Lee [11] it was found that vertically applied interchannel decorrelation was not as effective as horizontal decorrelation in terms of controlling the spread of image.The literature generally suggests that vertical localization relies on spectral cues. A number of researchers [12][13][14] have found that the higher the frequency of a pure tone the higher the perceived image position was regardless of the physical height of the presenting loudspeaker; a phenomenon referred to as the "pitch-height" effect in [15]. In the case of band-pass filtered noise signals, however, this effect was reported to be dependent on the physical height of the loudspeaker that presents the signal. For example, Roffler and Butler [16] found from their experiments using loudspeake...

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“…It is well documented in the literature that horizontal interchannel decorrelation between left and right loudspeaker signals relates directly to the perceived width of the horizontal auditory image [1]. This is due to a strong relationship between the interchannel cross-correlation (ICC) and interaural cross-correlation (IAC)-it is known that the IAC coefficient (IACC) is a good indicator of apparent source width (ASW) in concert hall acoustics, as dictated by decorrelated early reflections from lateral directions [2].…”

Section: Introductionmentioning

confidence: 99%

A Comparison between Horizontal and Vertical Interchannel Decorrelation

Gribben

2017

Applied Sciences

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Featured Application: 3D audio mixing and upmixing; creative sound design. Abstract:The perceptual effects of interchannel decorrelation on perceived image spread have been investigated subjectively in both horizontal and vertical stereophonic reproductions, looking specifically at the frequency dependency of decorrelation. Fourteen and thirteen subjects graded the horizontal and vertical image spreads of a pink noise sample, respectively. The pink noise signal had been decorrelated by a complementary comb-filter decorrelation algorithm, varying the frequency-band, time-delay and decorrelation factor for each sample. Results generally indicated that interchannel decorrelation had a significant effect on auditory image spread both horizontally and vertically, with spread increasing as correlation decreases. However, it was found that the effect of vertical decorrelation was less effective than that of horizontal decorrelation. The results also suggest that the decorrelation effect was frequency-dependent; changes in horizontal image spread were more apparent in the high frequency band, whereas those in vertical image spread were in the low band. Furthermore, objective analysis suggests that the perception of vertical image spread for the low and middle frequency bands could be associated with a floor reflection; whereas for the high band, the results appear to be related to spectral notches in the ear input signals.

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Efficient Phantom Source Widening

Cited by 15 publications

References 9 publications

Perceptual Band Allocation (PBA) for the Rendering of Vertical Image Spread with a Vertical 2D Loudspeaker Array

Perceptual Band Allocation (PBA) for the Rendering of Vertical Image Spread with a Vertical 2D Loudspeaker Array

2D-to-3D Ambience Upmixing based on Perceptual Band Allocation

A Comparison between Horizontal and Vertical Interchannel Decorrelation

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