UNIVERSITY OF NAIROBI SCHOOL OF ENGINEERING DEPARTMENT OF ELECTRICAL AND INFORMATION ENGINEERING FINAL YEAR PROJECT REPORT DESIGN OF A 4-WAY PASSIVE CROSS-OVER NETWORK BY ODHIAMBO TONNY SILVANCE REGISTRATION NUMBER: F17/1453/2011 SUPERVISOR: MR. S. L. OGABA EXAMINER: PROF.ABUNG’U This project was submitted as a partial fulfillment of the requirement for the award of Bachelor of Science Degree in Electrical and Information Engineering from University of Nairobi DECLARATION OF ORIGINALITY FACULTY/SCHOOL/INSTITUTE: ENGINEERING DEPARTMENT: ELECTRICAL AND INFORMATION ENGINEERING COURSE NAME: BACHELOR OF SCIENCE IN ELECTRICAL AND INFORMATION ENGINEERING NAME: ODHIAMBO TONNY SILVANCE REGISTRATION NUMBER: F17/1453/2011 COLLEGE: ARCHITECTURE AND ENGINEERING PROJECT: DESIGN OF A 4-WAY PASSIVE CROSS-OVER NETWORK PROJECT NUMBER: 112 1) I understand what plagiarism is and I am aware of the University policy on this regard. 2) I declare that this final year project is my original work and has not been submitted elsewhere for examination, award of degree or publication. Where other people’s work or my own work has been used, this has properly been acknowledged and referenced in accordance with University of Nairobi’s requirements. 3) I have not sought or used the services of any professional agencies to produce this work. 4) I have not allowed and shall not allow anyone to copy my work with the intention of passing it off as his/her own work. 5) I understand that any false claim in respect of this work shall result in disciplinary action, in accordance with University anti-plagiarism policy. Signature: ……………………………………..……………………………………..................... Date: ……………………………………..…………………………………………………. i DECLARATION AND CERTIFICATION This is my original work and has not been presented for any degree award in this or any other university. Information from other sources has been duly acknowledged. ………………………………………………………………………… ODHIAMBO TONNY SILVANCE F17/1453/2011 This report has been submitted to the Department of Electrical and Information Engineering, University of Nairobi with my approval as supervisor: …………………………………………………………………………….. MR. S. L. OGABA Date: …………………………. ii DEDICATION I would like to dedicate this project to my parents, my uncle Dr.Jared Oule, my entire family and my supervisor for their support during the period of my project. You have been the drive and inspiration that has kept me on course and track in pursuit of this very interesting but rather demanding and challenging career path iii ACKNOWLEDGEMENTS I would like to thank the Almighty God for giving me a good health, strength and the ability to carry out this project. I would also like to thank my supervisor, Mr. S. L. Ogaba for the continuous guidance he has shown from when the project started all through to its completion. My sincere appreciation goes to my classmates and close friends for their views, opinions on various aspects of the project and their constructive criticism that enabled me deliver the final piece of work to the best of my ability. iv ABBREVIATIONS SPL- Sound Pressure Levels AWG -American Wire Gauge OPAMP- Operational Amplifier mmf -Magneto motive force emf -Electromotive Force dB -Decibel Hz -Hertz Rms -Root mean square v Table of Contents 1 CHAPTER ONE- INTRODUCTION..................................................................................... 1 1.1 BACKGROUND INFORMATION ................................................................................. 1 1.2 PROBLEM DEFINITION ............................................................................................... 3 1.3 PROJECT JUSTIFICATION ........................................................................................... 3 1.4 OVERALL OBJECTIVE ................................................................................................. 4 1.5 SPECIFIC OBJECTIVES ................................................................................................ 4 2 CHAPTER TWO- LITERATURE REVIEW ......................................................................... 5 2.1 Filter networks.................................................................................................................. 5 2.1.1 Low-pass filters ......................................................................................................... 6 2.1.2 High pass filters ........................................................................................................ 6 2.1.3 Band-pass filters........................................................................................................ 7 2.1.4 Band-stop filters ........................................................................................................ 7 2.1.5 Butterworth response ................................................................................................ 8 2.1.6 Chebyshev response .................................................................................................. 9 2.1.7 Maximally flat time delay response (Bessel) .......................................................... 10 2.1.8 COMPARISON ...................................................................................................... 11 2.2 Speakers ......................................................................................................................... 12 2.2.1 SPEAKER PARAMETERS ................................................................................... 14 2.2.2 USABLE FREQUENCY RANGE ......................................................................... 17 2.2.3 POWER HANDLING ............................................................................................ 18 2.2.4 SENSITIVITY ........................................................................................................ 18 2.2.5 SIGNAL-TO-NOISE RATIO (SNR) ..................................................................... 19 2.2.6 DRIVER SIZES [7] ................................................................................................ 19 2.2.7 SPEAKER MODEL [8] [2] .................................................................................... 21 2.3 AUDIO CROSSOVER NETWORKS ........................................................................... 23 2.3.1 Active crossover...................................................................................................... 23 2.3.2 Passive crossover .................................................................................................... 24 2.4 Components (inductors and capacitors) ......................................................................... 25 vi 2.4.1 Inductors ................................................................................................................. 25 2.4.2 CAPACITORS ........................................................................................................ 27 2.5 ADDITIONAL USEFUL CIRCUITS ............................................................................ 29 2.5.1 1.Zobel network [11] .............................................................................................. 29 2.5.2 L-pad ....................................................................................................................... 33 2.5.3 Series-notch filter .................................................................................................... 33 2.5.4 Parallel notch (trap) filter ........................................................................................ 33 2.6 WORKING MECHANISM OF A CROSSOVER NETWORK ................................... 34 2.6.1 12dB crossover........................................................................................................ 34 3 CHAPTER 3- DESIGN ........................................................................................................ 36 3.1 Passive Crossover Circuit Design .................................................................................. 36 3.1.1 Selection of crossover frequency ............................................................................ 36 3.2 Component values determination ................................................................................... 38 3.2.1 Crossover points...................................................................................................... 38 3.2.2 Woofer (100W): ...................................................................................................... 39 3.2.3 Midrange1 (60W).................................................................................................... 40 3.2.4 Midrange2 (30W).................................................................................................... 40 3.2.5 Tweeter (10W) ........................................................................................................ 41 3.3 IMPEDANCE CURVES AND ZOBEL NETWORK DESIGN ................................... 45 3.3.1 1. woofer (wf090wa02) ........................................................................................... 46 3.3.2 specifications........................................................................................................... 46 3.3.3 midrange1(rs52an-8) ............................................................................................... 47 3.3.4 specifications........................................................................................................... 47 3.3.5 midrange2 (nd105-8) .............................................................................................