We analyzed the characteristics of sounds generated by local taps on a violin top plate. We examined the gravitational center of the frequency spectrum of tapping sounds and investigated its distribution over the top plate. The results showed that three categories of violins, with two violins in each category, had similar characteristics within the categories. The top plates of violins made after the 19th century in northern Italy had a high centroid frequency around the f-holes, and the tops of older Italian violins made before the 18th century showed a high centroid frequency only around the chin rest area, which was probably due to repeated coating with varnish. In addition, violin top plates with adjusted thickness of the wood to even out the pitch of the tapping sounds over the entire plate showed centroid frequencies with small variability over the top plates, similar to the old violins except around the chin rest area. These results indicate that violin top plates can be characterized by the sound of local taps on the violin plate, and suggest that tapping was an effective means of adjusting the thickness of the wood, especially before the early 19th century.

To clarify non-native speakers' perception of Japanese singleton and geminate stops, the perceptual boundary and discrimination sensitivity of these stops were investigated with native speakers of Japanese and Taiwanese Mandarin. The perceptual boundary of Japanese speakers varied with speaking rate, but Taiwanese Mandarin speakers had an almost constant perceptual boundary regardless of speaking rates. Taiwanese Mandarin speakers also had a much lower discrimination sensitivity, only about 15% that of native Japanese speakers. These results indicate that Taiwanese Mandarin speakers' perception of Japanese singleton and geminate stops is ambiguous due to their inadequate perceptual boundary and low discrimination sensitivity. Meanwhile, vowel devoicing preceding or following the stops decreased the discrimination sensitivity in both Japanese and Taiwanese Mandarin speakers, suggesting an effect of language-independent hearing processing on discrimination sensitivity instead of an effect of language-dependent speech processing. Our results suggest that multiple factors play a role in non-native speakers' perception of Japanese singleton and geminate stops.

A perception experiment and analyses were conducted to clarify the acoustic features of pop-out voice. Speech items pronounced by 779 native Japanese speakers were prepared for stimuli by mixing them with a babble noise that consisted of overlapping short sentences spoken by 10 Japanese speakers. Using a 5-point scale, 12 Japanese participants rated the pop-out score of the speech items listened using headphones. The scores and acoustic features of the speech items were investigated using correlation analysis and principal coordinate analysis. It was revealed that the pop-out score relates to the acoustic features such as overall intensity, relative intensity in the high-frequency range, fundamental frequency, dynamic feature of the spectrum, and a spectrum shape in high frequency. The results suggest that these are crucial acoustic features for the pop-out voice.

In acoustic music recording, spaced microphone positions typically give an impression of spaciousness and depth in the rendered sound scene. Inter-channel decorrelation, particularly at low frequencies, is thought to contribute to this effect, and cannot be achieved through coincident techniques. Higher order Ambisonics microphones have seen a rapid increase in popularity, despite their limitation as a coincident recording technique. In this article, recording and mixing strategies for the A-B spaced placement of HOA arrays are described combining the advantages of both: sound stage depth and stability, and the compatibility of b-format based mixing with respect to rendering for binaural and immersive 3D reproduction loudspeaker systems. Two tests were conducted to evaluate a) the suitability of various A-B spacings with regards to direct and/or ambient sound, and b) a novel two-dimensional mixing control tool, to study direct and ambient sound optimization. Results show that increased A/B spacing of HOA receivers correlates to more optimal presentation of ambient sound. Furthermore, users interacted with the mixing control tool differently when asked to optimize the sound scene for either direct or ambient sound, or both, providing support for our microphone placement and mixing techniques. This work points to new directions for the integration of HOA microphones with traditional recording techniques towards improved spatial representation of mediated music.

The term "Immersive Audio" is frequently used to describe an audio experience that provides to the listener the sensation of being fully immersed or "present" in a sound scene. This can be achieved via different presentation modes, such as surround sound (several loudspeakers horizontally arranged around the listener), 3D audio (with loudspeakers at, above and below listener ear level) and binaural audio to headphones. This article provides an overview of the recent MPEG standard, MPEG-H 3D Audio, which is a versatile standard that supports multiple immersive sound signal formats (channels, objects, higher order ambisonics), and is now being adopted in broadcast and streaming applications.

The present study subjectively evaluated loudspeaker reproductions of four different classical recordings in 0+2+0 (stereo), 0+5+0 (surround), 4+5+0 (surround with four height channels), each of which was downmixed from the original 9+10+3 (i.e. NHK 22.2), in terms of four attributes: listener envelopment (LEV), presence (i.e. sense of being there), overall tonal quality (OTQ) and overall listening experience (OLE). Prior to the main experiment, the playback levels of the upper and bottom loudspeaker layers relative to the middle layer level were subjectively adjusted for each of the original 9+10+3 recordings. It was found that the preferred levels of the upper and bottom layers were around 4 dB and 6 dB lower than that of the middle layer, on average. From multiple comparison listening tests, the perceived degradation from the original 9+10+3 to 4+5+0 was found to be significantly dependent on the recording technique used as well as the programme material. It was also found that 0+5+0 was not significantly different from 4+5+0 in general. Overall, LEV was most correlated with OLE, whilst Presence and OTQ tended to have a strong association.