###### Abstract
Coherent Image Source Modeling of Sound Fields in Long Spaces with a Sound-Absorbing Ceiling  
This paper by [PERSON] and [PERSON] [9] presents a coherent image source model for a simple yet accurate prediction of the sound field in long enclosures with a sound-absorbing ceiling. In the proposed model, the reflections on the absorbent boundary were separated from those on the reflective ones when evaluating the reflection coefficients. The model was compared with the classic wave theory, an existing coherent image source model and a scale model experiment. 10. Power Response and Modal Decay Estimation of the Room Reflections from Spherical Microphone Array Measurements Using Eigenbeam Spatial Correlation Model  
The application of the eigenbeam spatial correlation method in estimating the time frequency-dependent directional reflection powers and model decay times was presented by [PERSON] et al. [10]. The experimental results evaluated the application of the proposed technique for two rooms with distinct environments using their room impulse response measurements recorded by a spherical microphone array. The experimental observations proved that the proposed model is a promising tool in characterizing early and late reflections, which is beneficial in controlling the perceptual factors of room acoustics. Design of Concert or Conference Halls and Open-Plan Offices  
11. On the Sequence of Unmasked Reflections in Shoebox Concert Halls  
This work by [PERSON] et al. [11] is a tribute to the 90 th anniversary of Sir [PERSON] and his early innovative ideas of the acoustic signature of a hall. By analyzing the cross-sections of three concert halls, this study quantified the potential links between the architectural form of a hall, the resultant skeletal reflections and the properties of its acoustic signature. Whilst doing so, this study identified potential masking reflections through a visual and an analytical assessment of the skeletal reflections. 12. Comfort Distance--A Single-Number Quantity Describing Spatial Attenuation in Open-Plan Offices  
This study by [PERSON] and [PERSON] [12] introduces a new single-number quantity, the comfort distance \(r_{\text{C}}\), that integrates the quantities of the A-weighted sound pressure level of speech, \(\text{L}_{\text{P,A,S,4m}}\), and the spatial decay rate of speech, \(\text{D}_{\text{2,S}}\), used in ISO 3382-3. The new quantity describes the distance from an omnidirectional loudspeaker where the A-weighted sound pressure level of normal speech falls below 45 dB. The study explains why the comfort criterion level is set to 45 dB and explores the comfort distances in 185 offices reported in previous studies. 13. A Trial Acoustic Improvement in a Lecture Hall with MPP Sound Absorbers and FDTD Acoustic Simulations  
The feasibility and performance of micro-perforated panels (MPPs) when used as an acoustic treatment in lecture rooms were investigated in this work by [PERSON] et al. [13]. Three different micro-perforated steel specimens were first designed following existing predictive models and then physically manufactured through 3D additive metal printing. Numerical simulations were carried out using a full-spectrum wave-based method: a finite-difference time-domain (FDTD) code was chosen to better handle time-dependent signals as the verbal communication. The outcomes of the process showed the influence of the acoustic treatment in terms of the reverberation time (\(\text{T}_{\text{30}}\)) and sound clarity (\(\text{C}_{\text{50}}\)). 14. Mechanism Analysis of the Influence of Seat Attributes on the Seat Dip Effect in Music Halls  
In this paper [14], [PERSON] and [PERSON] performed numerical simulations on the basis of the finite element method to study the influence of seat attributes (seat height, seat spacing and seat absorption) on the seat dip effect (SDE) and the corresponding mechanism. The mapping of the sound spatial distribution related to the SDE was employed to observe the behavior of sound between the seats.