Sound source elevation using spectral notch filtering and directional band boosting in stereo loudspeaker reproduction

Chun, Chan Jun; Kim, Hong Kook; Choi, Seung Ho; Jang, Sei-Jin; Lee, Seok-Pil

doi:10.1109/tce.2011.6131171

Cited by 10 publications

(10 citation statements)

References 10 publications

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“…This is in general agreement with the literature that states frequencies around 8 kHz are important for vertical localization in the front median plane [16,17]. A previous study [42] has shown that boosting a band around 8 kHz alone can increase the vertical elevation of a broadband signal, based on Blauert's boosted band hypothesis [33], so potentially it could also control the vertical extent of an image as well. However, there seems to be an inherent dominance of the heightchannel signal when presenting the 8 kHz octave-band signals in vertical stereophony.…”

Section: Practical Implicationssupporting

confidence: 91%

The Frequency and Loudspeaker-Azimuth Dependencies of Vertical Interchannel Decorrelation on the Vertical Spread of an Auditory Image

Gribben¹

2018

J. Audio Eng. Soc.

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In horizontal stereophony, it is known that interchannel correlation relates to the horizontal spread of a phantom auditory image. However, little is known about the perceptual effect of interchannel correlation on vertical image spread (VIS) between two vertically-arranged loudspeakers. The present study investigates this through two subjective experiments: (i) a multiple comparison of relative VIS for stimuli with varying degrees of correlation; and (ii) the absolute measurement of upper and lower VIS boundaries for extreme stimuli conditions. Octave-band (center frequencies: 63 Hz to 16 kHz) and broadband pink noise signals have been decorrelated using two techniques: all-pass filtering and complementary comb-filtering. These stimuli were presented from vertically-spaced loudspeaker pairs at three azimuth angles (0• , ±30• , and ±110 • ), with each angle assessed discretely. Both the relative and absolute test results show no significant effect of vertical correlation on VIS for the 63 Hz, 125 Hz, and 250 Hz bands. For the 500 Hz band and above, there is a general tendency for VIS to increase as correlation decreases, which is observed for both decorrelation methods. This association is strongest at 0• azimuth for the 500 Hz and 1 kHz bands; at ±30• for 8 kHz and Broadband; and at ±110• for 2 kHz, 4 kHz, and 16 kHz. The 8 kHz band at ±30• has the strongest association of all conditions-post-hoc objective analysis indicates a potential relationship between HRTF localization cues (pinna filtering) and VIS perception within this frequency region. Furthermore, the absolute test results suggest that changes of VIS from interchannel decorrelation are fairly slight, with only the Broadband and 16 kHz bands showing a significant increase. The deviations of boundary scores also suggest a difficulty grading absolute VIS and/or potential disagreements among listeners.

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Section: Practical Implicationssupporting

confidence: 91%

The Frequency and Loudspeaker-Azimuth Dependencies of Vertical Interchannel Decorrelation on the Vertical Spread of an Auditory Image

Gribben¹

2018

J. Audio Eng. Soc.

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“…From the delta spectrum for the upper loudspeaker it can be seen that the upper loudspeaker is most dominant over the lower at around 8000 Hz. Chun et al [28], presented musical sources and speech to subjects from stereophonic loudspeakers arranged on the horizontal plane. The test stimuli first underwent HRTF modeling, followed by spectral notch filtering, directional band boosting, or a combination of both.…”

Section: Practical Implications and Future Workmentioning

confidence: 99%

Vertical Stereophonic Localization in the Presence of Interchannel Crosstalk: the Analysis of Frequency-Dependent Localization Thresholds

Wallis¹

2016

J. Audio Eng. Soc.

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Listening tests were conducted in order to investigate the frequency dependency of localization thresholds in relation to vertical interchannel crosstalk. Octave band and broadband pink noise stimuli were presented to subjects as phantom images from vertically arranged stereophonic loudspeakers located directly in front of the listening position. With respect to the listening position the lower loudspeaker was not elevated; the upper loudspeaker was elevated by 30• . Subjects completed a method of adjustment task in which they were required to reduce the amplitude of the upper loudspeaker until the resultant phantom image matched the position of the same stimulus presented from the lower loudspeaker alone. The upper loudspeaker was delayed with respect to the lower by 0, 0.5, 1, 5, and 10 ms. The experimental data demonstrated that the main effect of frequency on the localization threshold was significant, with the low frequency stimuli (125 and 250 Hz) requiring significantly less level reduction (less than 6 dB) than the mid-high (1, 2, and 8 kHz) frequency stimuli (9-10.5 dB reduction). The main effect of interchannel time difference (ICTD) on the localization thresholds for each octave band was found to be non-significant. For all stimuli interchannel level difference (ICLD) was always necessary, indicating that the precedence effect is not a feature of median plane localization.

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“…The results show that using the first three top predicted HRTF datasets out of 18, 80% of listeners are expected to find one of their favourite HRTF datasets when using the doublehidden-layer neural network. When the number of selected HRTF datasets reaches nine (taking Table 5 as an example, HRTF 16,18,17,7,6,5,11,8, and 4 are selected for Subject 1; taking Table 6 as an example, HRTF 4,16,18,7,10,12,14,6, and 11 are selected for Subject 2), the single-hidden-layer neural network is effective for 100% of population. When using the total error method (Zotkin et al, 2004), 15 HRTF datasets would be needed to be selected to satisfy all of the listeners.…”

Section: Resultsmentioning

confidence: 99%

Head-Related Transfer Function Selection Using Neural Networks

Yao¹,

Collins²,

Liang³

2017

Archives of Acoustics

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In binaural audio systems, for an optimal virtual acoustic space a set of head-related transfer functions (HRTFs) should be used that closely matches the listener's ones. This study aims to select the most appropriate HRTF dataset from a large database for users without the need for extensive listening tests. Currently, there is no way to reliably reduce the number of datasets to a smaller, more manageable number without risking discarding potentially good matches. A neural network that estimates the appropriateness of HRTF datasets based on input vectors of anthropometric measurements is proposed. The shapes and sizes of listeners' heads and pinnas were measured using digital photography; the measured anthropometric parameters form the feature vectors used by the neural network. A graphical user interface (GUI) was developed for participants to listen to music transformed using different HRTFs and to evaluate the fitness of each HRTF dataset. The listening scores recorded were the target outputs used to train the neural networks. The aim was to learn a mapping between anthropometric parameters and listener's perception scores. Experimental validations were performed on 30 subjects. It is demonstrated that the proposed system produces a much more reliable HRTF selection than previously used methods.

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Sound source elevation using spectral notch filtering and directional band boosting in stereo loudspeaker reproduction

Cited by 10 publications

References 10 publications

The Frequency and Loudspeaker-Azimuth Dependencies of Vertical Interchannel Decorrelation on the Vertical Spread of an Auditory Image

The Frequency and Loudspeaker-Azimuth Dependencies of Vertical Interchannel Decorrelation on the Vertical Spread of an Auditory Image

Vertical Stereophonic Localization in the Presence of Interchannel Crosstalk: the Analysis of Frequency-Dependent Localization Thresholds

Head-Related Transfer Function Selection Using Neural Networks

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