Vern Oliver Knudsen Papers LSC.1153
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Basics of Acoustics Contents
BASICS OF ACOUSTICS CONTENTS 1. preface 03 2. room acoustics versus building acoustics 04 3. fundamentals of acoustics 05 3.1 Sound 05 3.2 Sound pressure 06 3.3 Sound pressure level and decibel scale 06 3.4 Sound pressure of several sources 07 3.5 Frequency 08 3.6 Frequency ranges relevant for room planning 09 3.7 Wavelengths of sound 09 3.8 Level values 10 4. room acoustic parameters 11 4.1 Reverberation time 11 4.2 Sound absorption 14 4.3 Sound absorption coefficient and reverberation time 16 4.4 Rating of sound absorption 16 5. index 18 2 1. PREFACE Noise or unwanted sounds is perceived as disturbing and annoying in many fields of life. This can be observed in private as well as in working environments. Several studies about room acoustic conditions and annoyance through noise show the relevance of good room acoustic conditions. Decreasing success in school class rooms or affecting efficiency at work is often related to inadequate room acoustic conditions. Research results from class room acoustics have been one of the reasons to revise German standard DIN 18041 on “Acoustic quality of small and medium-sized room” from 1968 and decrease suggested reverberation time values in class rooms with the new 2004 version of the standard. Furthermore the standard gave a detailed range for the frequency dependence of reverberation time and also extended the range of rooms to be considered in room acoustic design of a building. The acoustic quality of a room, better its acoustic adequacy for each usage, is determined by the sum of all equipment and materials in the rooms. -
Physics of Music PHY103 Lab Manual
Physics of Music PHY103 Lab Manual Lab #6 – Room Acoustics EQUIPMENT • Tape measures • Noise making devices (pieces of wood for clappers). • Microphones, stands, preamps connected to computers. • Extra XLR microphone cables so the microphones can reach the padded closet and hallway. • Key to the infamous padded closet INTRODUCTION One important application of the study of sound is in the area of acoustics. The acoustic properties of a room are important for rooms such as lecture halls, auditoriums, libraries and theatres. In this lab we will record and measure the properties of impulsive sounds in different rooms. There are three rooms we can easily study near the lab: the lab itself, the “anechoic” chamber (i.e. padded closet across the hall, B+L417C, that isn’t anechoic) and the hallway (that has noticeable echoes). Anechoic means no echoes. An anechoic chamber is a room built specifically with walls that absorb sound. Such a room should be considerably quieter than a normal room. Step into the padded closet and snap your fingers and speak a few words. The sound should be muffled. For those of us living in Rochester this will not be a new sensation as freshly fallen snow absorbs sound well. If you close your eyes you could almost imagine that you are outside in the snow (except for the warmth, and bizarre smell in there). The reverberant sound in an auditorium dies away with time as the sound energy is absorbed by multiple interactions with the surfaces of the room. In a more reflective room, it will take longer for the sound to die away and the room is said to be 'live'. -
University of Montana Commencement Program, 1977
University of Montana ScholarWorks at University of Montana University of Montana Commencement Programs, 1898-2020 Office of the Registrar 6-12-1977 University of Montana Commencement Program, 1977 University of Montana (Missoula, Mont. : 1965-1994). Office of the Registrar Follow this and additional works at: https://scholarworks.umt.edu/um_commencement_programs Let us know how access to this document benefits ou.y Recommended Citation University of Montana (Missoula, Mont. : 1965-1994). Office of the Registrar, "University of Montana Commencement Program, 1977" (1977). University of Montana Commencement Programs, 1898-2020. 80. https://scholarworks.umt.edu/um_commencement_programs/80 This Program is brought to you for free and open access by the Office of the Registrar at ScholarWorks at University of Montana. It has been accepted for inclusion in University of Montana Commencement Programs, 1898-2020 by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. EIGHTIETH ANNUAL COMMENCEMENT UNIVERSITY OF MONTANA MISSOULA SUNDAY, JUNE THE TWELFTH NINETEEN HUNDRED AND SEVENTY-SEVEN FIELD HOUSE AUDITORIUM THE MARSHALS Walter E. Hill Chairman, Faculty Senate Professor of Chemistry Walter N. King R. Keith Osterheld Professor of English Professor of Chemistry The carillon concert by Dr. John Ellis preceding today’s commencement procession marks the first commencement music from Main Hall’s bell tower in almost ten years. This rededication concert has been made possible -
The Room Acoustics of Large Spaces
ROOMROOM ACOUSTICSACOUSTICS OFOF LARGELARGE SPACESSPACES TheThe TalaskeTalaske Group,Group, inc.inc. The Room Acoustics of Large Spaces Presented by: Rick Talaske The Talaske Group, inc. Oak Park, IL – U.S.A. ASA Tutorial Cancun, Mexico The photos of all projects are designed by The Talaske Group, inc. Presented to the Acoustical Society of America – Cancun, Mexico 02 December 2002 ROOMROOM ACOUSTICSACOUSTICS OFOF LARGELARGE SPACESSPACES TheThe TalaskeTalaske Group,Group, inc.inc. Acoustically speaking: What is a “Large” Room It is my pleasure to present this discussion in Cancun regarding the acoustics of large rooms. Generally, this topic is what the public thinks of when they hear the word “acoustics”. This is because of their experiences in churches, theatres and music halls. I hope to better your understanding about this interesting topic. Es un placer de estar aqui en Cancun y al al vez hacer un presentacion sobre la acustica en grandes espacios. Generalmente, la gente cada vez que se menciona la palabra “acusticaq”, la relacionan con iglesias, teatros ysalas musicales. Espero de que en esta presentacion, ustedes se lleven un mejor entendimiento del concepto de acustica. Presented to the Acoustical Society of America – Cancun, Mexico 02 December 2002 ROOMROOM ACOUSTICSACOUSTICS OFOF LARGELARGE SPACESSPACES TheThe TalaskeTalaske Group,Group, inc.inc. Acoustically speaking: What is a “Large” Room In this paper, a large room: • Schroeder’s Frequency is less than 50 Hz •fc = 2000*SR ( T60/V ) •fc is below the voice and music bandwidth. • Comb filtering is a lesser consideration. • Un espacio grande es un cuarto con muchas resonancias normales. Hay tantas resonancias que finalmente no son tan importantes. -
Paper One the Standing Wave Problem
LeadingEdge Systematic Approach Room Acoustic Principles - Paper One The Standing Wave Problem Sound quality problems caused by poor room acoustics. We all recognise that room acoustics can cause sound quality problems. But often the issues are not clearly described or discussed. Here we will cover some important considerations and principles of room acoustics problems. Treating your room should not be done in isolation from all the other system building considerations. Your thoughts about room acoustics treatment should be in conjunction with your requirements for mains, supports, system electronics, speakers and cables etc. None of these should be dealt with in isolation, and with regards to room acoustics it’s particularly important to be aware of some of the interactive nature of room acoustics, and other systematic faults. For example, a boomy bass could be caused by a room mode, but equally it could be caused by bass feedback from a wall and up into your system through the mains leads. If it’s your mains cables feeding back vibration that’s the dominant problem, spending money on room treatment may not correctly resolve the issue. Room acoustics problems can be grouped into the following categories. 1. Air mass problems: – Standing waves with sound pressure peaks and suck-outs (and associated velocity peaks) – Velocity generated intermodulation 2. Reflection problems – Unwanted reflected signals at the listening position – Raised reverberant background noise floor The behavior of a room’s air mass is the most important consideration with room treatment. A significant air mass problem is a fundamental destroyer of performance - uncontrolled room modes produce associated velocity intermodulation, which damages every aspect of musical reproduction. -
Acoustics 101 for Architects a Presentation of Acoustical Terminology and Concepts Relating Directly to the Design and Construction of an Architectural Space
Acoustics 101 for Architects A presentation of acoustical terminology and concepts relating directly to the design and construction of an architectural space. Low-tech descriptions, explanations, and examples. By: Michael Fay This essay is tailored to the one group of people who have more influence over a building's acoustics than any other; architects. The focus is on Architectural Acoustics, a field that is broader than most imagine. To do justice to the theme, we must briefly touch on many subordinate topics, most having a synergetic relationship bonding architecture and sound. This paper is based on fundamentals, not perfection. It covers most of the basics, and explores many modern and esoteric matters as well. You will be introduced to interesting and analytical subjects; some you may know, some you may never have considered. Here are a few examples of what you'll find by reading on: . What is sound and why is it so hard to manage or control? . The length of low- and high-frequency sound waves vary by as much as 400:1. Why does this disparity matter? . How and why do various audible frequencies behave differently when interacting with various materials, structures, shapes and finishes? . There are three acoustical tools available to both the architect and the acoustician. What are they? How can they benefit or hinder the work of each craft? . Room geometry: Why some shapes are much better than others. Examples and explanations. Reverberation and echo: How do they differ? Which is better, or worse, and why? How much is too much, or too little? . -
Room Acoustics and Reverberation
21m.380 · Music and Technology Recording Techniques & Audio Production Room acoustics & reverberation Session 18 · Wednesday, November 9, 2016 1 Pa1 presentations • • Flo: Randy Newman – A Few Words in Defense of Our Country (2006) 2 Announcement: Schlepping reminder • Please remember if you are signed up for pre- or post-class schlepping for either recording session on Mon, 11/14, Wed, 11/16. • Pre-class schlepping: Meet at , 10 minutes before class 3 Review 3.1 Recording session 1 3.2 Ed3 assignment • How to limit to −3 dB with ReaComp plugin – Large ratio – Small rms size – Short attack and release times • Review of setting up a gate 4 Audible effects of reflections & delays 4.1 Flutter echoes & resonances • Unpleasant flutter echoes tend to occur between hard, parallel walls • Real-world examples: Killian Hall – Front right stage area as seen from audience (floor & ceiling) – Center of room with folded-in wall panels (left & right wall) • Demo in Pd: Perceptual effect of delays – ≳ 30 ms: Audible as echoes – ≲ 30 ms: Audible as pitched resonance – why? 1 of 10 21m.380 · Room acoustics & reverberation · Wed, 11/9/2016 4.2 Comb filters +6 Figure 2. Comb filter frequency re- sponse (note linear 푥 axis −20 (dB) −40 gain −60 −80 푛 푛+1 푛+2 Δ푡 Δ푡 Δ푡 … Frequency 푓 (Hz) input • Result of mixing a sound with a copy of itself delayed by Δ푡: – Δ푡 = 푇, 2푇, 3푇, ⋯ = 푛 Constructive interference if 푓 푇 3푇 5푇 – Destructive interference if Δ푡 = 2 , 2 , 2 ,… • Sound example: pink noise, moving mic, reflective surface Delay Δ푡 • Can be enjoyed outdoors across mit campus; just combine: + – Broadband hvac noise – Reflections from nearby building walls – Moving observer output • Other ubiquituous examples: Figure 1. -
Cohen-Internet-History-2011.Pdf
International Journal of Technoethics, 2(2), 45-64, April-June 2011 45 Internet History Raphael Cohen-Almagor, University of Hull, UK ABSTRACT This paper outlines and analyzes milestones in the history of the Internet. As technology advances, it presents new societal and ethical challenges. The early Internet was devised and implemented in American research units, universities, and telecommunication companies that had vision and interest in cutting-edge research. The Internet then entered into the commercial phase (1984-1989). It was facilitated by the upgrading of back- bone links, the writing of new software programs, and the growing number of interconnected international networks. The author examines the massive expansion of the Internet into a global network during the 1990s when business and personal computers with different operating systems joined the universal network. The instant and growing success of social networking-sites that enable Netusers to share information, photos, private journals, hobbies, and personal as well as commercial interests with networks of mutual friends and colleagues is discussed. Keywords: ARPANET, History, ICANN, Innovation, Internet, Open Architecture, Packet Switching, Social Networking INTRODUCTION the biological kingdom. The third was Sigmund Freud (1856–1939), who acknowledged that History consists of a series of accumulated the mind is also unconscious and subject to the imaginative inventions. defence mechanism of repression, thus we are – Voltaire far from being Cartesian minds entirely transpar- ent to ourselves. And now, in the information Floridi (2009, 2010) argues that we are now revolution, we are in the process of dislocation experiencing the fourth scientific revolu- and reassessment of humanity’s fundamental tion. -
Room Acoustics
Room Acoustics Room Acoustics Fourth edition Heinrich Kuttruff Institut für Technische Akustik, Technische Hochschule Aachen, Aachen, Germany First published 1973 by Elsevier Science Publishers Ltd Second edition 1979 Third edition 1991 Fourth edition published 2000 by Spon Press 11 New Fetter Lane, London EC4P 4EE Simultaneously published in the USA and Canada by Spon Press 29 West 35th Street, New York, NY 10001 This edition published in the Taylor & Francis e-Library, 2001. Spon Press is an imprint of the Taylor & Francis Group © 1973, 1979, 1991 Elsevier Science Publishers; 1999, 2000 Heinrich Kuttruff The right of Heinrich Kuttruff to be identified as the Author of this Work has been asserted by him in accordance with the Copyright, Designs and Patents Act 18 All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Kuttruff, Heinrich. Room acousticHeinrich Kuttruff.–4th ed. p. cm. -
Characterizing Apparent Source Width Perception
CONTRIBUTIONS TO HEARING RESEARCH Volume 25 Johannes Käsbach Characterizing apparent source width perception Hearing Systems Department of Electrical Engineering Characterizing apparent source width perception PhD thesis by Johannes Käsbach Preliminary version: August 2, 2016 Technical University of Denmark 2016 © Johannes Käsbach, 2016 Cover illustration by Emma Ekstam. Preprint version for the assessment committee. Pagination will differ in the final published version. This PhD dissertation is the result of a research project carried out at the Hearing Systems Group, Department of Electrical Engineering, Technical University of Denmark. The project was partly financed by the CAHR consortium (2/3) and by the Technical University of Denmark (1/3). Supervisors Prof. Torsten Dau Phd Tobias May Hearing Systems Group Department of Electrical Engineering Technical University of Denmark Kgs. Lyngby, Denmark Abstract Our hearing system helps us in forming a spatial impression of our surrounding, especially for sound sources that lie outside our visual field. We notice birds chirping in a tree, hear an airplane in the sky or a distant train passing by. The localization of sound sources is an intuitive concept to us, but have we ever thought about how large a sound source appears to us? We are indeed capable of associating a particular size with an acoustical object. Imagine an orchestra that is playing in a concert hall. The orchestra appears with a certain acoustical size, sometimes even larger than the orchestra’s visual dimensions. This sensation is referred to as apparent source width. It is caused by room reflections and one can say that more reflections generate a larger apparent source width. -
Room Acoustics
Room Acoustics Prof. Unruh told us: - sound drops with distance squared - lower frequency can “bend” around walls - sound waves are additive - large build‐up of pressure near walls sound is 3db louder at walls - sound wavelength > walls “wiggle size” causes sound to scatter in different directions - so walls are oriented in direction and material to control reflections Terms: - long wavelengthlow frequency - short wavelengthhigh frequency - reflection wave bounces off object - diffraction edges used to spread in non‐linear directions - absorption objects turn waves to heat Reverberation Time reverberation: prolonged sound if incident and secondary/reflected waves are separated by <1ms sound continues to reverberate around a room until it’s energy has been fully absorbed by air and objects RT60 time for amplitude to decay by 60dB RT60 AND number of modes is proportional to the size of room, inversely prop to absorption in room complex frequency spectra ring longer more possibility of survival trick is to design a room where all frequencies have same RT60 If the RT60 s too short, all sounds very dry and hard to hear o ie: outdoor arenas, where the sound never reflects speech audibility = 1s <1s broadcasting/recording studio 1.5s‐2s in opera/concert halls 10s old stone cathedrals o good for a slow organ music; as long as there are very slow changes of pitch o but terrible for fast music/speech Reflection – Echoes perceiver in a room will hear sound which is a combo of the original sound and echoes from the walls, ceiling, -
The Effect on Room Acoustical Parameters Using a Combination Of
acoustics Article The Effect on Room Acoustical Parameters Using a Combination of Absorbers and Diffusers—An Experimental Study in a Classroom Emma Arvidsson 1,* , Erling Nilsson 2, Delphine Bard Hagberg 1 and Ola J. I. Karlsson 2 1 Engineering Acoustics, Lund University, John Ericssons väg 1, 221 00 Lund, Sweden; [email protected] 2 Saint-Gobain Ecophon AB, Yttervägen 1, 265 75 Hyllinge, Sweden; [email protected] (E.N.); [email protected] (O.J.I.K.) * Correspondence: [email protected] Received: 9 June 2020; Accepted: 2 July 2020; Published: 4 July 2020 Abstract: Several room acoustic parameters have to be considered in ordinary public rooms, such as offices and classrooms, in order to present the actual conditions, thus increasing demands on the acoustic treatment. The most common acoustical treatment in ordinary rooms is a suspended absorbent ceiling. Due to the non-uniform distribution of the absorbent material, the classical diffuse field assumption is not fulfilled in such cases. Further, the sound scattering effect of non-absorbing objects such as furniture are considerable in these types of rooms. Even the directional characteristic of the sound scattering objects are of importance. The sound decay curve in rooms with absorbent ceilings often demonstrate a double slope. Thus, it is not possible to use reverberation time as room parameter as a representative standalone acoustic measure. An evaluation that captures the true room acoustical conditions therefore needs supplementary parameters. The aim of this experimental study is to show how various acoustical treatments affect reverberation time T20, speech clarity C50 and sound strength G.