High Performance Loudspeakers: Optimising High Fidelity Loudspeaker Systems, Seventh Edition, by Martin Colloms. John Wiley & Sons, Inc., 2018. Paperback, 696 pp., $95. Available as an eBook, $79.99.
“Listen to that—that‘s what I mean by ‘cone cry!'”
It was 1979. I’d been taking part in a blind listening test of loudspeakers organized by Martin Colloms (footnote 1) for the British magazine Hi-Fi Choice and, after the formal sessions had ended, had asked Martin to explain something I’d heard. A drive-unit’s diaphragm produces cone cry when it resonates at a frequency unconnected with the musical signal it is being asked to produce; we had been using an anechoic recording of a xylophone, and one of the loudspeakers we’d been listening to was blurring the pitches of some of the instrument’s notes. Over the next few years, I took part in many of Martin’s listening tests, and the experience of learning from a master—not only of the craft of designing loudspeakers, but also of the art of judging them—provided this then-tyro audio critic with an invaluable education in how to listen, and what to listen for.
The first edition of Martin’s seminal textbook on loudspeaker design was published by Pentech Press in January 1978; the fifth edition (John Wiley & Sons, 1997) has been my constant companion the past 20 years, along with: Harry F. Olson’s Music, Physics and Engineering (second edition, Dover, 1967); Vance Dickason’s Loudspeaker Design Cookbook (sixth edition, Audio Amateur Publications, 2000); Philip Newell and Keith Holland’s Loudspeakers for Music Recording and Reproduction (first edition, Focal Press, 2008); and Floyd E. Toole’s Sound Reproduction: Loudspeakers and Rooms (first edition, Elsevier/Focal Press, 2008).
Both the technology and the theory of loudspeaker behavior have expanded immensely in the four decades since that first edition of Martin’s High Performance Loudspeakers, not least because of the introduction of PC-based measurement and analysis systems, which he examined in the sixth edition (2005), and complemented with psychoacoustic research data and an examination of the different demands made on home-theater speakers. In the seventh edition’s 10 chapters, each with up to 30 subchapters, Martin has expanded the sections on analysis and modeling, and included new sections on the increasingly popular Klippel and Comsol Multiphysics systems, as well as on the finite element analysis (FEA) of magnetic systems. He has added two new chapters, one on DSP integration into system design, and the second providing a worked-through example of the loudspeaker design process.
Chapter 1 is an overview of the field, followed by chapters on: the developments in all relevant technical areas; a detailed discussion of transducer design, including Air-Motion Transformers and Bending-Mode Radiators; a comprehensive discussion of the behavior of speakers when reproducing low frequencies and how that theoretical behavior is modified when a speaker is used in a room; and chapters on horn speakers, direct radiators, crossovers, and enclosures. Each chapter starts with first principles and ends in an examination of problems in implementation. While some mathematics had to be included, particularly concerning the modeling of a loudspeaker as an equivalent electrical circuit, Martin presents the math in a readily understandable manner.
Of particular interest to this observer of the field was Chapter 10, “Loudspeaker Assessment,” especially these sections: 10.2.1, “Transient Response Decay Rates and Coloration”; 10.2.4, “Direct Versus Reverberant Sound Balance”; 10.5.20, “Electrical Impedance,” which cites Keith Howard’s development of the Equivalent Peak Dissipation Resistance (EPDR) index to reveal how difficult a speaker can be for an amplifier to drive; 10.6.18, “Analogue and Digital Programme and Its Effect on Listening Tests”; and 10.6.30, “The High End: ‘High-Fidelity’ Sound Quality.”
A passage in that last section (p.628) excited a personal cri de coeur, if not quite a cri de cone, given Martin’s mentoring 40 years ago: “There is no examination or qualification for audio critics. The bar frequently is set by the editors of audio magazines who may be still less qualified for this task than the intending critic. Regarding web publications, it is perhaps unfortunate that almost anyone can set themselves up as an expert reviewer, this including the audio field.”
At the very beginning of the new edition, Martin writes: “Speech and music is noise with meaning. The recording and reproduction of sound is imperfect, and the imperfections in these processes reduce meaning and add noise. The art of the loudspeaker designer is the employment of science to help increase meaning for reproduced sound. . . . Science must serve art.”
Amen to that sentiment.
High Performance Loudspeakers: Optimising High Fidelity Loudspeaker Systems, Seventh Edition, is a must-have addition to the bookshelf of any audiophile who wants to learn everything there is to know about the art and science of loudspeaker design. Just one thing appears to be missing: While there is a detailed discussion of cone breakup behavior, the term cone cry doesn’t appear in the book’s almost 700 pages!—John Atkinson
Footnote 1: Based in the UK, Martin Colloms has written more than 1500 loudspeaker reviews for many magazines, including Stereophile; click here, for example. He is currently the technical editor of HiFi Critic magazine.
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