Thresholds

A working group is evaluating the American National Standard, “Criteria for Evaluating Room Noise” (ANSI/ASA S12.2-2019). This presentation will give an overview of our progress and areas of significant proposed change. The goal is to simplify the standard body to match the industry practice of using Noise Criterion curves and A-weighted sound levels as the primary noise level metrics. Less common criteria will be relegated to annexes, with explanations for when it may be appropriate to use these alternate rating systems. Since the beginning of this standard, there has been interest in qualifying the effects of spectral imbalance, temporal variation, and tone prominence. This talk will briefly mention proposals to address these aspects. A procedure for using Noise Criterion curves in one-third octave bands will also be explained. The goal is to solicit feedback from the industry to minimize the challenges associated with implementing this standard.

At the heart of Brown University’s Lindemann Performing Arts Center is a shape-shifting hall capable of supporting a wide range of performance types. Acoustic simulation played a crucial role in optimizing each of the hall’s five primary configurations during design. Leading up to the opening events 2023 and 2024, the lengthy commissioning and tuning process provided an invaluable opportunity to measure subtle and drastic changes in the hall’s form and materiality for comparison to the predictive simulation. Drawing from the Lindemann set, the paper compares modeled and measured data from the PAC to that from other projects designed using similar tools. The paper identifies points of uncertainty during design and delves into commonalities and differences between ray-based simulation and measurement in performance spaces of varying form. This paper will address the inherent complexities of approximating acoustic behavior with side by side comparison of measurement and simulated data, we will share insights that inform our future modeling process.

Situated along a popular motorcycle route, the Lindemann Performing Arts Center at Brown University posed a unique challenge to its design team — isolating the performance space from external road noise while adhering to the demanding RC 15 performance standard. This presentation provides a comprehensive exploration of the intricate development and testing of a robust yet relatively lightweight acoustic isolation façade system. The ultimate approach employed unconventional damping methods, ensuring compliance with dew point requirements. The paper delves into the nuances of the design process, with a focus on key elements such as glazing systems, roofing solutions, access doors, and gypsum buildups that push the boundaries of conventional construction, challenging the possible maximum length of a drywall fastener. Attendees will gain valuable insights into the innovative strategies implemented to achieve effective acoustic isolation without compromising the high-performance standards demanded by the Lindemann Performing Arts Center. This presentation serves as a valuable case study, offering a deeper understanding of the intersection between architecture, acoustics, and the practical challenges encountered in the design of performance spaces.

Purpose: To find out threshold of visual acuity for cataract surgery at a tertiary eye center of Iraq. Study Design: Descriptive observational. Place & Duration of Study: Ibn Al-Haitham Teaching Eye Hospital during the year 2022. Methods: It was a retrospective descriptive study in which 6650 patients who complained of visual impairment due to cataract, 30 to 80 years of age and either gender were included.Any intraocular pathology that leads to visual impairment other than cataract and congenital cataract were excluded. The best corrected visual acuity (BCVA) and the state of the fellow eye was also determined. Visual impairment was defined as mild; 6/9 - 6/18, moderate; 6/24 - 6/36 and severe visual impairment; 6/60 or less. Results: Data collected from 6650 cases showed 2625 (39.5%) males and 4025 (60.5%) females. Mild visual impairment was found in 875 (13.15%) patients, moderate was found in 175(2.63%) patients, and severe visual impairment was the most common type in 5250 (78.95%) patients. Conclusion: Most of the patients with cataract present late with severe impairment of visual acuity which requires national screening program with extra focuson risk groups. Nonetheless, these results are of potential use to planners of cataract screening outreach programs. It could be regarded as a preliminary study for further larger study on a national level to establish a scheme for patients’ diagnosis and referral to cataract surgery to get early diagnosis and shorten the waiting lists.

Sound data for variable refrigerant flow units are generally tested under anechoic conditions. This introduces significant error when extrapolating to different acoustic environments. Further, depending on the type of unit - ducted or non-ducted, the reported test configuration bears little resemblance to normal operating conditions. Quiet and bad data are not mutually exclusive; however, engineers must be aware of the challenges and potential pitfalls associated with manufacturer data. This paper will compare available manufacturer data tested in anechoic and reverberant chambers and their respective standards, as well as field measured data in common, lightly furnished spaces.

As the first notes from a performer are expressed on a newly constructed stage, we acousticians close our eyes and hold our breath. We do this not because our reputation is on the line but rather to focus all our attention on our auditory system. We listen for the impulse response, hearing the loudness, clarity, bass ratio, and profile of the decay. We open our eyes as the performer continues, pairing our visual and auditory senses to gain still more information. We look for those surfaces placed around the stage to support the direct sound. We follow the vibrations into the larger volume and map their path as they bounce around the room and rain down a shower of energy that envelops us in warm sonic embrace. Did we achieve the acoustic signature we designed? We will discuss our methods for mapping out the recording of two-dimensional time and energy in an impulse responses onto three-dimensional space with rendering software in order to analyze and tune our performances spaces.

People with serious mental illness die up to 20 years younger than others in the same age group, with people of color showing even earlier death. The social disadvantages experienced by this group-for example, poverty, criminal legal involvement, and immigration-are further determinants of this disparity. Peer health navigators (PHNs) are people with experiences of recovery who may share a racial-ethnic background, history of poverty, experience with criminal legal systems, or immigration status with current patients and who assist in practical and timely tasks that help people engage with fragmented health systems. This column describes the PHN practice, including the putative components that define it.