The Virtual Acoustic Room
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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. -
The Pennsylvania State University
The Pennsylvania State University The Graduate School EFFECTS OF PERTURBATIONS ON THE REVERBERANT SOUND FIELD OF A ROOM A Thesis in Acoustics by Sumeet Sanjay Gawali © 2020 Sumeet Sanjay Gawali Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science May 2020 ii The thesis of Sumeet Gawali was reviewed and approved by the following: Stephen Thompson Research Professor Thesis Advisor Daniel Russell Teaching Professor of Acoustics and Distance Education Coordinator Robert Smith Assistant Research Professor Victor Sparrow Director of Graduate Program in Acoustics and United Technologies Corporation Professor of Acoustics iii ABSTRACT The reverberant sound field in a room, with all surfaces of the room being stationary, depends on the objects present in the room and their reflective or absorptive features and partly expressed in the reverberation time of the room. However, if perturbations are introduced in the sound field, either by moving objects in a room or by introducing new moving objects in the room with reflective or absorptive characteristics, the reverberant sound field undergoes modifications as the reflections change and in turn change how sound waves in a room interfere with each other at different locations in the room. These changes can be observed by making a comparison measurement between the frequency response of the room when it is stationary and when it is being perturbed. In this research effort, the impact on the time averaged sound field of a person moving through four candidate rooms was examined to assess the impact of this type of practical and easily achieved level of perturbation on a room. -
Loudspeakers and Rooms for Sound Reproduction—A Scientific Review*
PAPERS Loudspeakers and Rooms for Sound Reproduction—A Scientific Review* FLOYD E. TOOLE ([email protected]) Harman International Industries, Inc., Northridge, CA 91329, USA The physical measures by which acousticians evaluate the performance of rooms have evolved in large performance spaces—concert halls. They rely on assumptions that become progressively less valid as spaces get smaller and more acoustically absorptive. In listening rooms the loudspeakers and the rooms interact differently below and above a transition region around 300 Hz, similar to the Schroeder frequency in large rooms. Above this transition we need to understand our reactions to reflected sounds; below it the modal behavior of the space is the dominant factor. A review of the scientific literature reveals that natural reflections in small rooms are at levels where they are perceptible, and their subjectively judged effects range from neutral to positive. At low frequencies the long-standing problem of room reso- nances can be alleviated substantially through the use of multiple subwoofers, thereby pro- viding similarly good bass to several listeners in a room. A provocative observation has to do with human adaptation to the complexities of reflective rooms, and the extent to which it allows us to localize sounds correctly in direction and distance, and to hear much of the true timbral nature of sound sources. In the case of loudspeakers, an analysis of comprehensive anechoic data is found to be sufficient to provide a good prediction of sound quality, above the low-bass frequencies, as subjectively judged in a normal room. Although the interactions of loudspeakers and listeners in small rooms are becoming clearer, there are still gaps in our understanding. -
Measurements for Loudspeaker Modeling Files
Excelsior Audio Design & Services 2130 Shadwell Court 704.675.5435 4471 Posterity Court Gastonia, NC 28056 www.excelsior-audio.com Gastonia, NC 28056 Audio & Acoustical Consulting, Design, and Measurement 22 March 2017 Charlie Hughes Measurements for Loudspeaker Modeling Files Loudspeaker modeling files are most often used with acoustical modeling programs such as EASE, Focus, CATT-Acoustic, and others to help determine how well the loudspeakers cover the audience areas and how much “spill” there is on the room’s surfaces. Some of these programs also allow for the investigation of additional metrics like reverberation time, clarity, speech transmission index (STI), and more. For many of these items it is important to have accurate data about the characteristics of the loudspeakers that are used in the models. Errors in the data used for these modeling programs will often lead to errors in the results the programs generate. In this article we will details some of the requirements to help assure good measurement data for use with loudspeaker modeling. It is also possible to use some of these loudspeaker modeling files to help optimize the design of crossover filters for the loudspeaker system. Since these modeling files have both on-axis and off-axis data the effects of the crossover and equalization filters used for each pass band can be seen in the overall directivity response of the loudspeaker system. We will also show an example of this in a follow-up article. While it is sometimes possible to measure a multi-transducer loudspeaker system as a single radiating, full-range device, these measurements may be limited in their use. -
Microphone Techniques for RECORDING
A Shure Educational Publication MICROPHONE TECHNIQUES RECORDING Microphone Techniques for Table of Contents RECORDING Introduction: Selection and Placement of Microphones ............. 4 Section One .................................................................................. 5 Microphone Techniques ........................................................ 5 Vocal Microphone Techniques ............................................... 5 Spoken Word/“Podcasting” ................................................... 7 Acoustic String and Fretted Instruments ................................ 8 Woodwinds .......................................................................... 13 Brass ................................................................................... 14 Amplified Instruments .......................................................... 15 Drums and Percussion ........................................................ 18 Stereo .................................................................................. 21 Introduction: Fundamentals of Microphones, Instruments, and Acoustics ....................................................... 23 Section Two ................................................................................ 24 Microphone Characteristics ................................................. 24 Instrument Characteristics ................................................... 27 Acoustic Characteristics ....................................................... 28 Shure Microphone Selection Guide .................................... -
Microphone Techniques
A Shure Educational Publication MICROPHONE TECHNIQUES RECORDING Microphone Techniques for Table of Contents RECORDING Introduction: Selection and Placement of Microphones ............. 4 Section One .................................................................................. 5 Microphone Techniques ........................................................ 5 Vocal Microphone Techniques ............................................... 5 Spoken Word/“Podcasting” ................................................... 7 Acoustic String and Fretted Instruments ................................ 8 Woodwinds .......................................................................... 13 Brass ................................................................................... 14 Amplified Instruments .......................................................... 15 Drums and Percussion ........................................................ 18 Stereo .................................................................................. 21 Introduction: Fundamentals of Microphones, Instruments, and Acoustics ....................................................... 23 Section Two ................................................................................ 24 Microphone Characteristics ................................................. 24 Instrument Characteristics ................................................... 27 Acoustic Characteristics ....................................................... 28 Shure Microphone Selection Guide .................................... -
Remix Theory
~ SpringerWienNewYork Eduardo Navas .000• 00.00 .000. 00000 .000.••••• •••••• 0000 ••0 •• 00.00 0.0.0 00000 .0.0 • 00.00 00.00 00.00 .00.0••••• •••••• 0000 .000• 00.00 0.0.0 00000 • 000. ••••• .000• 00.00 .000. 00000 • 000• .000• •••••00.00 .000. •••••• 0000 •••••• 000• .000•••••• 0.0.0 00.00 • 000• 00.00 00.00 .000.••••• •••••• 0000 .000• .00.0••••• 00.00 00.00 • 000. ••••• ••••• .000• 00.00 THE AESTHETICS OF SAMPLING SpringerWienNewYork Eduardo Navas, Ph.D. Post-Doctoral Research Fellow Information Science and Media Studies University of Bergen, Norway With financial support of The Department of Information Science and Me- dia Studies at The University of Bergen, Norway. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is con- cerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machines or similar means, and storage in data banks. Product Liability: The publisher can give no guarantee for all the informa- tion contained in this book. The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific state- ment, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. © 2012 Springer-Verlag/Wien SpringerWienNewYork is part of Springer Science+Business Media springer.at Cover Image: Eduardo Navas Cover Design: Ludmil Trenkov Printing: Strauss GmbH, D-69509 Mörlenbach Printed on acid-free and chlorine-free bleached -
Design and Implementation of Digital Signal Processing Hardware for a Software Radio Reciever
Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-2008 Design and Implementation of Digital Signal Processing Hardware for a Software Radio Reciever Jake Talbot Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Electrical and Computer Engineering Commons Recommended Citation Talbot, Jake, "Design and Implementation of Digital Signal Processing Hardware for a Software Radio Reciever" (2008). All Graduate Theses and Dissertations. 265. https://digitalcommons.usu.edu/etd/265 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. DESIGN AND IMPLEMENTATION OF DIGITAL SIGNAL PROCESSING HARDWARE FOR A SOFTWARE RADIO RECIEVER by Jake Talbot A report submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Computer Engineering Approved: Dr. Jacob H. Gunther Dr. Todd K. Moon Major Professor Committee Member Dr. Aravind Dasu Committee Member UTAH STATE UNIVERSITY Logan, Utah 2008 ii Copyright © Jake Talbot 2008 All Rights Reserved iii Abstract Design and Implementation of Digital Signal Processing Hardware for a Software Radio Reciever by Jake Talbot, Master of Science Utah State University, 2008 Major Professor: Dr. Jacob H. Gunther Department: Electrical and Computer Engineering This project summarizes the design and implementation of field programmable gate ar- ray (FPGA) based digital signal processing (DSP) hardware meant to be used in a software radio system. The filters and processing were first designed in MATLAB and then imple- mented using very high speed integrated circuit hardware description language (VHDL). -
The Routledge Companion to Remix Studies
THE ROUTLEDGE COMPANION TO REMIX STUDIES The Routledge Companion to Remix Studies comprises contemporary texts by key authors and artists who are active in the emerging field of remix studies. As an organic interna- tional movement, remix culture originated in the popular music culture of the 1970s, and has since grown into a rich cultural activity encompassing numerous forms of media. The act of recombining pre-existing material brings up pressing questions of authen- ticity, reception, authorship, copyright, and the techno-politics of media activism. This book approaches remix studies from various angles, including sections on history, aes- thetics, ethics, politics, and practice, and presents theoretical chapters alongside case studies of remix projects. The Routledge Companion to Remix Studies is a valuable resource for both researchers and remix practitioners, as well as a teaching tool for instructors using remix practices in the classroom. Eduardo Navas is the author of Remix Theory: The Aesthetics of Sampling (Springer, 2012). He researches and teaches principles of cultural analytics and digital humanities in the School of Visual Arts at The Pennsylvania State University, PA. Navas is a 2010–12 Post- Doctoral Fellow in the Department of Information Science and Media Studies at the University of Bergen, Norway, and received his PhD from the Program of Art and Media History, Theory, and Criticism at the University of California in San Diego. Owen Gallagher received his PhD in Visual Culture from the National College of Art and Design (NCAD) in Dublin. He is the founder of TotalRecut.com, an online com- munity archive of remix videos, and a co-founder of the Remix Theory & Praxis seminar group. -
Countercultures and Popular Music
COUNTERCULTURES AND POPULAR MUSIC A translated and edited edition of a special issue of Volume! The French Journal of Popular Music Studies (Éditions Mélanie Seteun). Additional articles published in both ‘countercultures’ issues of Volume! can be found at: http://www.cairn.info/revue-volume.htm and http://volume.revues.org. Volume! is the only French peer-reviewed popular music studies journal. Created in 2002 by Marie-Pierre Bonniol, Samuel Étienne and Gérôme Guibert, it is published independently by the Éditions Mélanie Seteun, a publishing association specialising since 1998 in the cultural sociology of popular music. Biannual special issues deal with various topics in popular music studies, in a multidisciplinary perspective. It is also included on the online international academic portals Cairn.info and Revues.org. Volume! is classified by the French AERES and abstracted/indexed on the International Index to Music Periodicals, the Répertoire International de Littérature Musicale and the Music Index. This page has been left blank intentionally Countercultures and Popular Music Edited by SHEILA WHITELEY University of Salford, UK JEDEDIAH SKLOWER Université Sorbonne Nouvelle, Paris 3, France © Sheila Whiteley and Jedediah Sklower and the contributors 2014 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior permission of the publisher. Sheila Whiteley and Jedediah Sklower have asserted their rights under the Copyright, Designs and Patents Act, 1988, to be identified as the editors of this work. Published by Ashgate Publishing Limited Ashgate Publishing Company Wey Court East 110 Cherry Street Union Road Suite 3-1 Farnham Burlington, VT 05401-3818 Surrey, GU9 7PT USA England www.ashgate.com British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. -
The Discrete Hilbert Transform
The Swiss Army Knife of Digital Networks ___________________ by Richard Lyons and Amy Bell ___________________ This article describes a general discrete-signal network that appears, in various forms, inside many DSP applications. So the "DSP Tip" for this column is for every DSP engineer to become acquainted with this network. Figure 1 shows how the network's structure has the distinct look of a digital filter—a comb filter followed by a 2nd-order recursive network. However, we do not call this unique general network a filter because its capabilities extend far beyond simple filtering. Through a series of examples, we illustrate the fundamental strength of the network: its ability to be reconfigured to perform a surprisingly large number of useful functions based on the values of its seven control parameters. Comb 2nd-order recursive network (biquad) x(n) y(n) + - -1 a0 z b z -N 0 a -1 1 z b1 c1 a b 2 2 Figure 1. General discrete-signal processing network. The general network has a transfer function of -1 -2 -N b0 + b1z + b2z H(z) = (1 -c1z ) -1 -2 . (1) 1/a0 -a1z -a2z From here out, we'll use DSP filter lingo and call the 2nd-order recursive network a "biquad" because its transfer function is the ratio of two quadratic polynomials. The tables in this article list various signal processing functions performed by the network based on the an, bn, and c1 coefficients. Variable N is the order of the comb filter. Included in the tables are depictions of the network's impulse response, z-plane pole/zero locations, as well as frequency-domain magnitude and phase responses. -
Room Acoustics and Sound Reinforcement Systems
Room Acoustics and Sound Reinforcement Systems Tadeusz Fidecki Contents Introduction ................................................................................................................................. 3 1. Wave theory approach ................................................................................................... 3 1.1 Eigenfrequencies and eigenmodes .......................................................................... 3 1.2 Modal density ............................................................................................................ 8 1.3 Loss factor and reverberation time ........................................................................... 8 1.4 Conclusion ................................................................................................................ 11 2. Statistical method ........................................................................................................... 12 2.1 The room response to the sound radiation ............................................................... 12 2.2 Reverberation in enclosures ..................................................................................... 13 2.3 Growth of energy in enclosure .................................................................................. 13 2.4 Decay of energy in enclosure ................................................................................... 14 2.5 Reverberation time ..................................................................................................