Editing Thiele/Small parameters (section)

==History==

The 1925 paper<ref name="RiceKellog_1925"/> of [[Chester W. Rice]] and [[Edward W. Kellogg]], fueled by advances in [[Radio frequency|radio]] and electronics, increased interest in direct radiator loudspeakers. In 1930, [[A. J. Thuras]] of [[Bell Labs]] [[patent]]ed (US Patent No. 1869178) his "Sound Translating Device" (essentially a vented box) which was evidence of the interest in many types of [[Loudspeaker enclosure|enclosure]] design at the time.

Progress on loudspeaker enclosure design and analysis using [[Acoustical engineering|acoustic analogous circuits]] by academic acousticians like [[Harry F. Olson]] continued in the 1940s.  In 1952, [[Bart N. Locanthi]] developed equivalent electrical models of common loudspeaker configurations.<ref>{{cite journal
  |title=Application of electric circuit analogies to loudspeaker design problems
  |author=Locanthi, Bart N
  |journal=IRE Trans. Audio
  |volume=6
  |pages=15
  |year=1952
  |url=https://www.aikenamps.com/images/Documents/speaker.pdf }}</ref>  In 1954 when [[Leo Beranek|Leo L. Beranek]] of the [[Massachusetts Institute of Technology]] published ''Acoustics'',<ref name="Beranek1954"/> a book summarizing and extending the [[Acoustical engineering|electroacoustics]] of the era. [[J. F. Novak]] used novel simplifying assumptions in an analysis in a 1959 paper<ref name="NovakIRE_1959"/><ref name="NovakJAES_1959"/> which led to a practical solution for the response of a given loudspeaker in sealed and vented boxes, and also established their applicability by empirical measurement. In 1961, leaning heavily on Novak's work, [[A. N. Thiele]] described a series of sealed and vented box "alignments" (i.e., enclosure designs based on electrical filter theory with well-characterized behavior, including frequency response, power handling, cone excursion, etc.) in a publication in an Australian journal.<ref name="Thiele1961"/> This paper remained relatively unknown outside Australia until it was re-published in the ''[[Audio Engineering Society|Journal of the Audio Engineering Society]]'' in 1971.<ref name="Thiele_VBPt1"/><ref name="Thiele_VBPt2"/> It is important to note that Thiele's work neglected enclosure losses and, although the application of filter theory is still important, his alignment tables now have little real-world utility due to neglecting enclosure losses.

Many others continued to develop various aspects of loudspeaker enclosure design in the 1960s and early 1970s. From 1968 to 1972, [[John Ernest Benson|J. E. Benson]] published three articles<ref name="Benson1996"/> in an Australian journal that thoroughly analyzed [[Loudspeaker enclosure#Closed-box enclosures|sealed]], [[Bass reflex|vented]] and [[Passive radiator (speaker)|passive radiator]] designs, all using the same basic model, which included the effects of enclosure, leakage and port losses. Beginning in June 1972, [[Richard H. Small]] published a series of very influential articles on direct radiator loudspeaker system analysis,<ref name="SmallDR"/> including closed-box,<ref name="Small_CBPt1"/><ref name="Small_CBPt2"/> vented-box,<ref name="Small_VBPt1"/><ref name="Small_VBPt2"/><ref name="Small_VBPt3"/><ref name="Small_VBPt4"/> and passive-radiator<ref name="Small_PRPt1"/><ref name="Small_PRPt2"/> loudspeaker systems, in the ''Journal of the Audio Engineering Society'', restating and extending Thiele's work. These articles were also originally published in Australia, where he had attended graduate school, and where his thesis supervisor was J. E. Benson. The work of Benson and Small overlapped considerably, but differed in that Benson performed his work using computer programs and Small used [[Analog Computer|analog simulators]]. Small also analyzed the systems including enclosure losses. Richard H. Small and Garry Margolis, the latter of [[JBL]], published an article in the ''Journal of the Audio Engineering Society'' (June 1981),<ref name="MargolisSmall"/> which recast much of the work that had been published up till then into forms suited to the programmable calculators of the time.