DOCSLIB.ORG

Electroacoustic Devices: Microphones and Loudspeakers This Page Intentionally Left Blank Electroacoustic Devices: Microphones and Loudspeakers

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Electroacoustic Devices: Microphones and Loudspeakers This Page Intentionally Left Blank Electroacoustic Devices: Microphones and Loudspeakers Electroacoustic Devices: Microphones and Loudspeakers This page intentionally left blank Electroacoustic Devices: Microphones and Loudspeakers Edited by Glen Ballou AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Focal Press is an imprint of Elsevier Focal Press is an imprint of Elsevier 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA Linacre House, Jordan Hill, Oxford OX2 8DP, UK © 2009 ELSEVIER Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Library of Congress Cataloging-in-Publication Data Application submitted British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN: 978-0-240-81267-0 For information on all Focal Press publications visit our website at www.elsevierdirect.com Typeset by: diacriTech, Chennai, India 09 10 11 12 5 4 3 2 1 Printed in the United States of America Contents Part I Electroacoustic Devices 1. Microphones Glen Ballou, Joe Ciaudelli, Volker Schmitt 1.1 Introduction 4 1.2 Pickup Patterns 5 1.2.1 Omnidirectional Microphones 5 1.2.2 Bidirectional Microphones 9 1.2.3 Unidirectional Microphones 10 1.3 Types of Transducers 23 1.3.1 Carbon Microphones 23 1.3.2 Crystal and Ceramic Microphones 24 1.3.3 Dynamic Microphones 26 1.3.4 Capacitor Microphones 33 1.3.5 Electret Microphones 48 1.4 Microphone Sensitivity 49 1.4.1 Open-Circuit Voltage Sensitivity 49 1.4.2 Maximum Power Output Sensitivity 50 1.4.3 Electronic Industries Association (EIA) Output Sensitivity 51 1.4.4 Various Microphone Sensitivities 53 1.4.5 Microphone Thermal Noise 53 1.5 Microphone Practices 54 1.5.1 Placement 54 1.5.2 Grounding 56 1.5.3 Polarity 57 1.5.4 Balanced or Unbalanced 59 1.5.5 Impedance 59 1.6 Miscellaneous Microphones 61 1.6.1 Pressure Zone Microphones (PZM) 61 1.6.2 Lavalier Microphones 69 1.6.3 Head-Worn Microphones 72 1.6.4 Base Station Microphones 75 1.6.5 Differential Noise-Canceling Microphones 76 1.6.6 Controlled-Reluctance Microphones 77 1.6.7 Handheld Entertainer Microphones 77 1.6.8 Pressure-Gradient Condenser Microphones 79 1.6.9 Interference Tube Microphones 82 1.6.10 Rifle Microphones 89 1.6.11 Parabolic Microphones 90 v vi Contents 1.6.12 Zoom Microphones 91 1.6.13 Automatic Microphone Systems 94 1.6.14 PolarFlex™ Microphone System 95 1.7 Stereo Microphones 98 1.7.1 Coincident Microphones 98 1.7.2 XY Stereo Technique 100 1.7.3 The ORTF Technique 103 1.7.4 The M/S Stereo Technique 104 1.7.5 The Stereo Boom Microphone 111 1.7.6 SASS Microphones 113 1.7.7 Surround Sound Microphone System 115 1.8 Microphones for Binaural Recording 120 1.8.1 Artificial Head Systems 120 1.8.2 In the Ear Recording Microphones 124 1.9 USB Microphones 126 1.10 Wireless Communication Systems 127 1.10.1 Criteria for Selecting a Wireless Microphone 129 1.10.2 Receiving Antenna Systems 134 1.10.3 Companding 137 1.10.4 Waterproof Wireless Microphone Systems 138 1.11 Multichannel Wireless Microphone and Monitoring Systems 139 1.11.1 Introduction 139 1.11.2 Frequencies 140 1.11.3 Spacing 140 1.11.4 Frequency Deviation 140 1.11.5 Frequency Coordination 140 1.11.6 Transmitter Considerations 143 1.11.7 Receiver Considerations 146 1.11.8 Antennas 147 1.11.9 Wireless Monitor Systems 151 1.11.10 System Planning for Multichannel Wireless Systems 152 1.11.11 Future Considerations: Digital Wireless Transmission 154 1.11.12 Conclusion 155 1.12 Microphone Accessories 156 1.12.1 Inline Microphone Processors 156 1.12.2 Windscreens and Pop Filters 160 1.12.3 Shock Mounts 165 1.12.4 Stands and Booms 169 1.12.5 Attenuators and Equalizers 170 1.13 Microphone Techniques 171 1.13.1 Stereo Micing Techniques 173 1.13.2 Microphone Choice 174 1.13.3 Microphone Characteristics 174 1.13.4 Specific Micing Techniques 176 1.13.5 Conclusion 192 Acknowledgments 192 References 192 Bibliography 193 Contents vii 2. Loudspeakers Jay Mitchell 2.1 Introduction 196 2.1.1 Uses of Loudspeakers 196 2.1.2 Loudspeaker Components 197 2.2 Transducer Types 197 2.2.1 Electrodynamic Transducers 198 2.2.2 Diaphragm Types 199 2.2.3 Suspension Methods 201 2.2.4 Mechanical Construction 201 2.3 Compression Drivers 203 2.4 Electrostatic Transducers 206 2.5 Piezoelectric Loudspeakers 210 2.6 Motor Design Considerations 213 2.6.1 Output Limitations 215 2.6.2 Heat Transfer Designs for High-Power Woofers 219 2.7 Radiator Types 221 2.7.1 Direct Radiators 221 2.7.2 Cone Radiators 221 2.7.3 Dome Radiators 222 2.7.4 Ring Radiators 222 2.7.5 Panel Radiators 223 2.7.6 Horns 223 2.8 Loudspeaker Systems 234 2.8.1 Configuration Choices 235 2.8.2 Types of Loudspeaker Systems 236 2.8.3 Performance Issues in Multiway Systems 237 2.8.4 Line Arrays 241 2.8.5 Crossovers 243 2.8.6 Acoustic Boundaries 249 2.8.7 Conclusion 251 2.9 Characterization of Loudspeaker Performance 252 2.9.1 Motivation 252 2.9.2 Efficiency and Sensitivity 252 2.9.3 Network Transfer Function 253 2.9.4 Loudspeaker Transfer Function 253 2.9.5 Impedance 255 2.9.6 Distortion 257 2.9.7 Characterization for Design Purposes 257 2.9.8 Characterization for the User 258 2.10 Direct Radiation of Sound 261 2.10.1 Acoustics of Radiators 261 2.10.2 Direct Radiator Enclosure Design 265 2.10.3 Horns 270 2.11 Loudspeaker Testing and Measurement 271 2.11.1 Linear Transfer Function 271 2.11.2 Chart Recorders 272 viii Contents 2.11.3 Real Time Analyzers 273 2.11.4 Time-Windowed Measurements 274 2.11.5 Swept Sine Measurements 276 Reference 277 Bibliography 277 3. Loudspeaker Cluster Design Ralph Heinz 3.1 Why Array? 279 3.2 Array Problems and Partial Solutions: A Condensed History 280 3.3 Conventional Array Shortcomings 280 3.4 Conventional Array Shortcoming Analysis 284 3.5 Coincident Acoustical Centers: A Practical Approach 286 3.5.1 TRAP Horns: A New Approach 286 3.5.2 TRAP Performance 289 3.6 Low Frequency Arrays: Beneficial Interference 289 3.6.1 Horizontal Woofer Arrays: Maintaining Wide Dispersion 289 3.6.2 Vertical Woofer Arrays 291 3.7 Line Arrays and Digitally Steerable Loudspeaker Column Arrays 292 3.7.1 What Affects Intelligibility 293 3.7.2 Measuring Intelligibility 294 3.7.3 Architecture and Room Acoustics 295 3.7.4 Line Arrays 296 3.7.5 DSP-Driven Vertical Arrays 300 3.7.6 Multichannel DSP Can Control Array Height 306 3.7.7 Steerable Arrays May Look Like Columns But They Are Not 306 Index 311 Part I Electroacoustic Devices This page intentionally left blank Section 1 Microphones Glen Ballou, Joe Ciaudelli, Volker Schmitt 1.1 Introduction 1.5.3 Polarity 1.2 Pickup Patterns 1.5.4 Balanced or Unbalanced 1.2.1 Omnidirectional 1.5.5 Impedance Microphones 1.6 Miscellaneous Microphones 1.2.2 Bidirectional 1.6.1 Pressure Zone Microphones Microphones (PZM) 1.2.3 Unidirectional 1.6.2 Lavalier Microphones Microphones 1.6.3 Head-Worn 1.3 Types of Transducers Microphones 1.3.1 Carbon Microphones 1.6.4 Base Station Microphones 1.3.2 Crystal and Ceramic 1.6.5 Differential Noise- Microphones Canceling Microphones 1.3.3 Dynamic Microphones 1.6.6 Controlled-Reluctance 1.3.4 Capacitor Microphones Microphones 1.3.5 Electret Microphones 1.6.7 Handheld Entertainer 1.4 Microphone Sensitivity Microphones 1.4.1 Open-Circuit Voltage 1.6.8 Pressure-Gradient Sensitivity Condenser Microphones 1.4.2 Maximum Power Output 1.6.9 Interference Tube Sensitivity Microphones 1.4.3 Electronic Industries 1.6.10 Rifle Microphones Association (EIA) Output 1.6.11 Parabolic Microphones Sensitivity 1.6.12 Zoom Microphones 1.4.4 Various Microphone 1.6.13 Automatic Microphone Sensitivities Systems 1.4.5 Microphone Thermal 1.6.14 PolarFlex™ Noise Microphone System 1.5 Microphone Practices 1.7 Stereo Microphones 1.5.1 Placement 1.7.1 Coincident Microphones 1.5.2 Grounding 1.7.2 XY Stereo Technique Electroacoustic Devices: Microphones and Loudspeakers Copyright © 2009 by Focal Press, Inc.
Load more

Recommended publications
  • LIT9785 RFA/PWR-14X
    RFA-14x ® ® car audiofor RFR-14x Tweeters fanatics Operation & Installation RFA-14x PWR-14x power ® Dear Customer, Congratulations on your purchase of the world's finest brand of car audio speakers. At Rockford Fosgate we are fanatics about musical reproduction at its best, and we are pleased you chose our product. Through years of engineering expertise, hand craftsman- ship and critical testing procedures, we have created a wide range of products that reproduce music with all the clarity and richness you deserve. For maximum performance we recommend you have your new Rockford Fosgate product installed by an Authorized Rockford Fosgate Dealer, as we provide specialized training through Rockford Technical Training Institute (RTTI). Please read your warranty and retain your receipt and original carton for possible future use. Great product and competent installations are only a piece of the puzzle when it comes to your system. Make sure that your installer is using 100% authentic installation accessories from Connecting Punch in your installation. Connecting Punch has everything from RCA cables and speaker wire to Power line and battery connectors. Insist on it! After all, your new system deserves nothing but the best. To add the finishing touch to your new Rockford Fosgate image order your Rockford wearables, which include everything from T-shirts and jackets to hats and sunglasses. To get a free brochure on Rockford Fosgate products and Rockford wearables, in the U.S. call 602-967-3565 or FAX 602-967-8132. For all other countries, call +001-602- 967-3565 or FAX +001-602-967-8132. PRACTICE SAFE SOUND™ CONTINUOUS EXPOSURE TO SOUND PRESSURE LEVELS OVER 100dB MAY CAUSE PERMANENT HEARING LOSS.
    [Show full text]
  • Measurement of Loudspeaker Directivity
    KLIPPEL E-learning, training 8 2018-12-19 Hands-On Training 8 Measurement of Loudspeaker Directivity 1. Objective of the Hands-on Training - Understanding the need for assessing loudspeaker directivity - Introducing the basic theory of acoustic holography and field separation - Applying Near Field Scanning techniques to loudspeakers - Interpreting the results of Near Field Scanning - Developing skills for performing practical measurements 2. Requirements 2.1. Previous Knowledge of the Participants It is recommended to do the Klippel Training #2 “Vibration and Radiation Behavior of Loudspeaker’s Membrane” before starting this training. 2.2. Minimum Requirements The objectives of the hands-on training can be accomplished by using the results of the measurement provided in a Klippel database (.kdbx) dispensing with a complete setup of the KLIPPEL measurement hardware. The data may be viewed by downloading the measurement software dB-Lab from www.klippel.de/training and installing them on a Windows PC. 2.3. Optional Requirements If the participants have access to a KLIPPEL Analyzer System, we recommend to perform some additional measurements on loudspeakers provided by instructor or by the participants. In order to perform these measurements, you will also need the following additional software and hardware components: Klippel Robotics KLIPPEL Analyzer (DA2 or KA3) Near Field Scanner Amplifier Microphone 3. The Training Process Read the following theory to refresh your knowledge required for the training. Watch the demo video to learn about the practical aspects of the measurement. Answer the preparatory questions to check your understanding. Follow the instructions to interpret the results in the database and answer the multiple- choice questions off-line.
    [Show full text]
  • Winter 2018 Revel Is a Unique Loudspeaker Company
    Winter 2018 Revel is a unique loudspeaker company that exists for the design and production of using off-the-shelf transducers. Most were no such research existed, the Harman innovative, no-compromise products that using transducers from OEM sources that Corporate Acoustics Research Group — a expand the performance envelope of home would allow very limited customization. A group of researchers and engineers world- sound reproduction. manufacturer could ask for performance wide that are unquestionably without peer in targets, but the vendor would essentially the loudspeaker industry — do the research Revel was launched as a distinguished ‘choose a voice coil from column A and a required for us to make the world’s finest Harman International brand in January spider from column B,’ and the manufacturer loudspeakers. 1996, when company Chairman Dr. Sidney would have to take what they could get. Harman asked Kevin Voecks, now Product Revel has been in the enviable position from Revel was the first brand to embrace the Development Manager, of HARMAN Luxury the start of having extraordinarily talented multi-channel listening lab approach to Audio Group, to create the world’s finest transducer engineers who design each of our testing, where double-blind listening tests loudspeakers, period — no strings attached. drivers from the ground up to be ideally suited have been refined to such a degree that "Indeed, Dr. Harman remained true to his for each specific application. Revel has led the results yield repeatable metrics, rather word, never attempting to influence Revel’s the way with innovative transducers that allow than the unreliable and unverifiable results technical or sonic direction," notes Voecks.
    [Show full text]
  • PRODUCT GUIDE Table of Contents
    PRODUCT GUIDE Table of Contents “We are integrators building FastLoc pg. 2 products for integrators.” pg. 4 – Sean McDermott, CEO FIT CS pg. 6 Bipole/Dipole pg. 8 Dual Tweeter pg. 10 Great design, integration, and excellence in manufacturing all play critical roles in creating Current Audio products. InWall pg. 12 Current Audio is backed by an award winning and inspiring team of seasoned designers, engineers, and installation experts, LCR pg. 14 holding title as CE Pro Top 100 Integrators with years of patented, custom audio product development, manufacturing and pg. 16 experience. CECS ProSeries pg. 18 You don’t have to go far to see how the electronics industry has changed over the last few decades but what can we say about the actual speakers? Subwoofer pg. 20 pg. 22 With decades of sales and installation know-how in the speaker business, as integrators we Outdoor understand the installers’ wants, needs, and struggles because we are installers ourselves. ILS pg. 24 pg. 25 Current Audio presents proven and innovative products that excel in quality and performance Amp which will save you time and money. We carefully listen to and respond to our customers’ Bracket pg. 26 suggestions and needs. The result of our listening has modeled a superior company and product line. SpeKap/WWP pg. 27 pg. 28 Current Audio is holder of fifteen international patents. This is a true testament of our Transformer determination to bring a fresh set of innovative ideas to what has become known as stagnant part of the industry. Speaker Selector/Volume Control pg.
    [Show full text]
  • The New 700 Series Studio Sound Comes Home
    The new 700 Series Studio sound comes home Bring the breathtaking clarity and definition of studio sound home with the new 700 Series. Replacing the CM Series, the range combines studio-grade 800 Series Diamond technologies with purpose-built innovations to elevate home audio to an entirely new level. And all this from room-friendly cabinets designed to fit beautifully into your home environment. The new 700 Series. Inspired by recording studios. Made for living rooms. 702 S2 Featuring a Carbon Dome™ tweeter in a solid-body housing and a decoupled Continuum™ midrange, the 700 Series’ flagship floorstander brings studio-quality sound to your home audio set up. The speaker relays textural details with goosebump-inducing accuracy, making even large- scale recordings sound stunningly lifelike. 705 S2 With state of the art features such as the tweeter-on- top design borrowed from the 800 Series Diamond, this uncompromising high performance two-way speaker reveals subtle nuances in music others miss. Even challenging instruments such as the piano are conveyed with uncanny realism, presence and transparency. 703 S2 A substantial, uncompromising three-way floorstander built to fill even the largest rooms with full-blooded, realistic sound. Powerful bass lines come roaring to life, while the speaker’s dedicated Continuum™ midrange driver and Carbon Dome tweeter lend an astonishing clarity to vocals and treble effects. 704 S2 A slim, elegant floorstander designed to blend unobtrusively into your home environment, while providing the commanding presence of a much larger speaker. Music is a revelation, with details picked out in pin-sharp detail and with exceptional realism.
    [Show full text]
  • Current-Driving of Loudspeakers
    IV First Edition 2010 Copyright © 2010 Esa T. Meriläinen All rights reserved Homepage: www.current-drive.info ISBN: 1450544002 EAN-13: 9781450544009 Published in the U.S.A. through a print-on-demand service While every precaution has been taken to ensure the accuracy of infor- mation presented herein, the author and publisher assume no responsi- bility for errors or omissions. Nor is any liability assumed for any pos- sible damages or losses arising from the use of this information. 1 SOME PARALLELS 1.1 The Era of Direct Current The issue whether loudspeakers should be excited by a voltage or current signal is quite well comparable to a dispute that took place over a century ago, concerning whether the production and distribution of electricity should operate on direct or alternating current. Thomas A. Edison had opened, in New York, the world's first power generating plant, that supplied a DC voltage of 110 volts for an area of a few square kilometres in Manhattan. Another pioneer of electrical tech- nology, Croatian-born Nikola Tesla, instead, believed strongly in the su- periority of the three-phase AC system he had developed. In 1886, George Westinghouse founded an electric company to utilize the inven- tions and patents of Tesla and to compete with Edison. Edison was not at all pleased seeing a rivaling system threatening his dominating stature in power production. The conflict caused a breach between Edison and Tesla, and a public struggle about which system would become prevalent. Edison even resorted to a trick campaign in his attempt to defame AC power, that he thought was dangerous.
    [Show full text]
  • High-Fidelity Uniform-Directivity Loudspeakers
    www.PiSpeakers.com High-Fidelity Uniform-Directivity Loudspeakers Lots of people are experimenting with waveguides and constant directivity loudspeakers these days. This has been a π Speakers flagship design for decades, so naturally we understand the attraction to this approach, and the surge in popularity amongst manufacturers and DIY hobbyists alike. This paper explores the technologies and development history of waveguides and constant directivity loudspeakers, with emphasis on high-fidelity designs rather than sound production or public address. We’ll also explore some of the different design approaches that have been used, illuminating the strengths and weaknesses of each. While this paper primarily addresses loudspeaker system design rather than horn or driver design, an understanding of the acoustic properties of various horns and waveguides is needed to properly implement them. Towards that aim, we shall explore some of the kinds of horns used in high-fidelity constant-directivity loudspeakers. After a brief history of the evolution of the state of the art, we will explore the advantages of uniform-directivity in a high-fidelity loudspeaker, and why it is a desirable trait. There are those that are unconcerned with directivity in a home high-fidelity speaker, and who would place little emphasis on it. To them, the whole concept of constant directivity is a goal only for sound reinforcement speakers. Many audiophiles hold this belief, and in fact, until somewhat recently, convincing them otherwise was an uphill battle. Of course, once the unconvinced audiophile heard a true high-fidelity quality sound system that produced a uniform sound field, all academic argument was made moot.
    [Show full text]
  • Speaker Measurements Importance of Time & Phase Objective Gauges of Fidelity Isfactory Conclusions About Audio Components
    3 Why Flat Response? Auricle Publishing Number 13 2005 $35.00 US 4 How Can You Tell? 8 Speaker Measurements Importance of Time & Phase Objective Gauges of Fidelity isfactory conclusions about audio components. I’ll This Journal will explain how to interpret speaker offer examples in an attempt to explain why. 9 measurements so you’ll know what the test results Evaluating mean and what they can tell you about a If you hate listening to a component Time & Phase product’s potential for accurate per- or system, no group of meas- formance. These objective meas- urements can magically 11 urements can be very valuable to make that experience Minimizing consumers because they show enjoyable. On the other Stored Energy which products to avoid there- hand, if a component by narrowing the field of con- or system is demon- 13 tenders and minimizing the strably inaccurate Evaluating number of components you’ll learn to hate it Energy Storage you’ll have to audition. sooner or later (based on my expe- 16 Objective measurements rience) when you Importance don’t tell the entire story of learn how to hear of Bass course, and they raise the the flaw(s) that may age-old questions about initially have gone 17 objective versus subjective unnoticed. Evaluating Bass product evaluation. Performance I’m convinced that you The Debate have a far better chance for 19 A debate we encounter frequently in audio long-term satisfaction if you fol- Thiel CS2.4 involves the validity of “objective” versus “subjective” low the high fidelity approach and Review evaluations.
    [Show full text]
  • A Straightforward One-Seat Stereo Tuning Process and Some Notes About Why It Works
    A Straightforward One-Seat Stereo Tuning Process and Some Notes About Why it Works The Process Note 1: This process assumes the input to your DSP is confirmed as a flat, two-channel and in phase signal, like that of an aftermarket radio. Note 2: In an active system in which your tweeters are driven by an amplifier directly, install a capacitor in series with each tweeter to protect it from erroneous crossover settings, turn on and turn off pops and other failures that may destroy them. Choose a capacitor value that provides a -3dB point about an octave below the tweeter’s Fs. Note 3: This is not an iterative process in which you listen and then make an adjustment or two and then listen again to confirm an improvement. Once you’ve confirmed that all the speakers are connected and playing, there’s no need to listen until after all of the settings have been made and you’ve put away the RTA. Polarity, delay, crossovers, level and EQ, confirmation and additional level adjustments. That’s the order. 1. Confirm that electrical polarity is correct. Use the markings on the speakers and the amps, a polarity checker or the UMI-1 and a scope. Do not set polarity by listening for a center image from speaker pairs! 2. Put the mic in the car. 3. Measure from the center of each speaker to the microphone. Estimate a straight line from the sub to the mic no matter which way the sub is facing. If your system includes passive crossovers for the front speakers, measure to the midbass driver in a 3-way system or the midrange in a 2-way system.
    [Show full text]
  • Measurements
    Rear Loudspeaker Transducer Measurements Loudspeaker’s frequency response was measured in-room, using windowed MLS techniques. The 0.5m set-up and results are presented on the pictures below. Tweeter frequency/phase response Woofer frequency/phase response Tweeter’s frequency response is fully usable for the design purposes, however, woofer’s frequency response lacks information in the low-end and is really unsuitable for developing equalization. Consequently, woofer’s frequency response was measured in-room, using close- mike technique. The way it works, is that you need to measure driver’s frequency response, then port’s frequency response, and add them together. Port response has to be scaled down by several decibels, due to the difference in effective diameter between port and driver: 20*log(Driver_Radius / Port_Radius) In my case, the port SPL was shifted down by -10dB. On the top of this, you need to add pre-calculated diffraction for this box. The technique was also described in details in UE3 User’s Manual, http://www.bodziosoftware.com.au/UE%20V3%20Manual.zip All operations and measurements were performed using SoundEasy V18. As a starting point, I calculated diffraction of the front panel. Dimensions are 23cm x 46cm. Diffraction plot is shown below. Next, close-mike measurements are performed on driver and port. Port is scaled down by -10dB. Driver’s SPL is stored in Buffer 1 and port is stored in Buffer 2 - see below. Next, port and driver SPL are summed in Master Buffer and the Master Buffer is copied to Buffer 5. Then, I added pre-calculated diffraction to Buffer 5 – see step 5 above.
    [Show full text]
  • Control/Studio Monitors
    CONTROL/STUDIO MONITORS PH5VS The PH5-vs is ideal for a variety of studio and multimedia applications due to clean, precise mid-range design and low distortion. 40 watts RMS per channel drive a 5 1/4" woofer and 3/4" tweeter in a video-shielded ABS enclosure. Sold in pairs with cable and DC power supply included. (6.3" W x 9.3" H x 6.5" D, B2030-TRUTH weight/pair 11 lb.) sold in pairs. LIST Monitors PH5VS ..................................................................................................................299.00 A 6.75" 2-way active bi-amplified monitor system with CALL FOR PRICE balanced XLR and 1/4 TRS inputs. Features magnetic shielding, separate 75 and 35 Watt amplifiers, active crossover and response form 50-21k Hz. LIST B2030A-TRUTH ..pair of active monitors ............339.99 B2030P-TRUTH ..pair of passive monitors, PH3S needs amplifier ......................159.99 These high quality, video-shielded self-powered speakers are in a league of their own. CALL FOR PRICE With an extremely small footprint, Audix PH3-s are versatile solution for applications requiring high-definition sound in a compact, transportable shielded package. 20 watts of power per channel (RMS) delivers a clean, surprisingly big sound through a 3-1/2" woofer and a 3/4" tweeter. Sold in pairs with cable and DC power supply. (4.75" W x 7.5" H x 4.75" D, weight- pair 8 lb.) sold in prs. LIST PH3S......................................................................................................................199.00 MONITOR-1C CALL FOR PRICE This monitor system is ide- ally suited for fixed installa- tions, multimedia, home recording studios, audio/video productions and surround-sound sys- tems.
    [Show full text]
  • Measuring Loudspeakers, Part One John Atkinson, November 1998
    Measuring Loudspeakers, Part One John Atkinson, November 1998 This series of articles was initially written (in slightly different form), as a paper presented at the 103rd Audio Engineering Society Convention, New York, September 1997. The preprint, "Loudspeakers: What Measurements Can Tell Us—And What They Can't Tell Us!," AES Preprint 4608, is available from the AES, 60 East 42nd Street, Room 2520, New York, NY 10165- 0075. The AES internet site, offers a secure transaction page for credit-card orders. What's the point of measuring the performance of an audio component if what is owners do is listen to it? Of the 20 or so regularly published English-language consumer magazines on audio, only three routinely publish rigorous loudspeaker measurements: Hi-Fi News & Record Review in the UK; Audio and Stereophile in the US (footnote 1). It would seem that supporting a reviewer's subjective impression of how a loudspeaker sounds with measured data is an idea that is out of fashion these days. But without measuring a loudspeaker's performance, how can a "Golden Ears" reviewer avoid falling into error? I believe that it is the responsibility of any magazine that publishes judgments on audio components to fully describe their performance. And that cannot be done without measurements. For electronic components, measuring their effect on an input signal is relatively straightforward (though correlating those effects with perceived sound quality is not a job for the fainthearted). But for many decades, getting a true idea of how a loudspeaker performed was only possible using swept sinewaves in large, expensive anechoic chambers.
    [Show full text]