Acoustics 201 : Loudspeaker measurements
What you'll learn
- Measure frequency response of a speaker or sound system.
- Make distortion measurements.
- Measure impedance and create impedance plots.
- Measure the Thiele / Small parameters of a speaker driver.
- Create FRD and ZMA files for crossover design applications.
- How to make anechoic frequency response measurements in your own room.
Requirements
- Basics on acoustics and enclosure design.
- Microphone designed for measuring.
- Device for impedance and other electrical measurements.
Description
Learn how to measure frequency response
The first thing you will learn from this course is to measure the frequency response of a certain speaker driver, loudspeaker or sound system. The difficult part is to get an anechoic response without an anechoic chamber. Using different measuring techniques and with the help of intuitive software, you will learn how to measure the full frequency bandwidth anechoically in your own living room. This will help you set up your audio system using measured data, or it can be used to design crossovers for your particular DIY loudspeaker.
A little bit of electrical engineering
A sound system is a combination of both acoustical and electrical parts. You will also learn how to measure impedance and create impedance plots. Measure different electrical components like capacitors, inductors and resistors. Also, if you have an unknown speaker driver you will learn how to measure the Thiele / Small parameters without much fuss.
Dip your feet into crossover design
While this course will not teach you how to design a crossover, it will show you how to create FRD and ZMA files. These are frequency response and impedance files which are used in crossover design apps. At the end of the course I will show you how to load these files into such program, and tryout different circuits and see how adding crossover components behave. A comprehensive course about crossovers will be released in the near future.
Do I need certain equipment?
Yes, you will need 2 core pieces of gear :
A measurement microphone (like miniDSP UMIK-1).
A device for measuring impedance (like Dayton Audio DATS v2 (recently released v3 as of 2020).
These are roughly 100$ each, but you will get a more comprehensive list of the equipment needed inside the course. With alternatives that you can buy, or more cheaper options. Also, some accessories that will make your life easier are included in the list.
Software option
For the different acoustical measurements we are going to use Room EQ Wizard (or REW). This is a free to use software. Usually, acoustics software are quite expensive and difficult to follow. However, REW is free and quite intuitive to use. Pretty much a complete package. It only misses one function, which I consider important. Don't worry, we're are not going to step up to those complicated application. I devised an Excel spreadsheet which handles this shortcoming. You will find the spreadsheet inside the course.
Nov 2018 Update - Added English subtitles.
June 2019 Update - Corrected a measurement error for the 3-way speaker and added more info to that section
Jan 2020 Update - Update the equipment list
Who this course is for:
- Audiophiles who want to learn more about sound and speaker systems.
- DIY-ers who want to build their own loudspeakers.
- People who want to set up their audio gear using measurements.
- People who want to set the foundation for learning how to design a crossover.
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Course content
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Instructor
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- 4,045 Students
- 5 Courses
Hi! My name is Marius and I'm from Romania. I majored in economics and computer science, and have a college and masters degree in this field. Regarding the audiophile part of me, I started to intensely study this area since several years ago. It’s difficult to get a college degree in this field, since there are only a few universities around the world which have this specialization (from what I know, In Europe, there is a famous one in Denmark, and another in UK). The closest specialization would be electrical engineering, but I wanted something a bit more specific. So instead of going abroad for studies, I decided to study at home in my free time. The things I find important or interesting I write them down on my blog. Here is a list of books I have read, some of them even twice or three times :
1. Master Handbook of Acoustics by F. Alton Everest, Ken Pohlmann (McGraw Hill Professional, 2009)
2. Introduction to Sound System Design and Electro-Acoustics by Peter Swarte (DHvV Interactive Lab, 2014)
3. Audio Engineering Explained by Douglas Self (Taylor & Francis, 2012)
4. Electroacoustics by Mendel Kleiner (CRC Press, 2013)
5. The Audio Expert: Everything You Need to Know About Audio by Ethan Winer (Focal Press, 2012)
6. Electroacoustic Devices: Microphones and Loudspeakers 1st Edition by Glen Ballou (Focal Press, 2009)
7. The Complete Guide to High-End Audio 5th Edition by Robert Harley (Acapella Publishing, 2015)
8. Introduction to Loudspeaker Design: Second Edition by John L. Murphy (True Audio, 2014)
9. Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms 1st Edition by Floyd Toole, (Focal Press, 2008)
10. Basic Electricity (Dover Books on Electrical Engineering) 2nd Edition by Bureau of Naval Personnel (Dover Publications, 1970)
11. Distortion: The Cause Of Harmonics And The Lie Of THD by Dan P. Bullard (CreateSpace Independent Publishing Platform, 2015)
12. Audio Engineer's Reference Book 2nd Edition by Michael Talbot-Smith (Focal Press, 2001)
13. Loudspeaker and Headphone Handbook 3rd Edition by John Borwick (Focal Press, 2001)
14. Loudspeaker Design Cookbook 7th Edition by Vance Dickason (Audio Amateur Pubns, 2005)
15. How to Build Speaker Enclosures by Alexis Badmaieff and Don Davis (Howard W. Sams & Co, 1966)
16. Making Sense of Sound by Alvis J. Evans (Prompt Publications, 1992)
17. Designing, Building, and Testing Your Own Speaker System with Projects 4th Edition by David Weems (McGraw-Hill Education TAB, 1996)
18. Testing Loudspeakers by Joseph D'Appolito (Audio Amateur Pubns,1998)
19. Speaker Building 201: A Comprehensive Course in Speaker Design by Ray Alden (Audio Amateur Pubns, 2004)
20. Loudspeaker Recipes: Book 1 : Four Two-Way Systems by Vance Dickason (Audio Amateur Pubns, 1994)
21. The Sound Reinforcement Handbook 2nd Edition by Gary Davis and Ralph Jones (Yamaha, 1988)
The difficult part Is making sense of all the information from a text book, since there is no mentor to guide you. There is a lot of study to be done, when you have a question that needs answering. Hopefully, the courses I’m about to publish, will save you from this ordeal and give you concentrated and easy to digest information.