|
Horn Resources and References
One of the most important papers written on horn design is:
W. Marshall Leach, Jr., On the Specification of Moving-Coil Drivers for Low-Frequency Horn-Loaded Loudspeakers: Preprint 1405. Also reprinted in the AES anthology: "Loudspeakers Volume 2."
Software for calculating horns based on Leach is ML Util.zip by Michael Zhang (see the Readmefirst1.txt file). Make sure you read and understand Leach's paper first.
Internet Resources
Print References
- Introduction to Electroacoustics and Audio Amplifier Design by W. Marshall Leach, Kendall/Hunt Publishing Company; 2nd edition (September 1999). The book contains horn theory as well as amplifier design. Currently out of print.
- Audio Transducers, a new book on loudspeaker theory by Earl Geddes contains a chapter on waveguides (part of horn theory). Geddes' waveguide theories lead him to question the common Webster equations for horns.
- Horn Loudspeaker Design by Jack Dinsdale. Book published by Audion Magazine in Italy, 1999. Language is both English and Italian in the same book. Comes with computer software for generating horn contours. Available from Audion.
- Acoustical Engineering by Harry Olson. 50 years old but still in print. The horn bible. Available from Old Colony ~$60.
- The Show Horn, by Bruce Edgar. In Speaker Builder Two/1990 (Volume 11, Number 2) available from Old Colony. A bass horn article with good theory.
Articles in the Audio Engineering Society (AES) publications, available as preprints here at the AES website.
- W. Marshall Leach, Jr., On the Specification of Moving-Coil Drivers for Low-Frequency Horn-Loaded Loudspeakers: Preprint 1405. Also reprinted in the AES anthology: "Loudspeakers Volume 2."
- D.B. Keele, Jr., Low-Frequency Horn Design Using Thiele/Small Driver Parameters: Preprint 1250
- Richard H. Small, Suitability of Low-Frequency Drivers for Horn-Loaded Loudspeaker Systems: Preprint 1251.
New theory on "Waveguides" as an alternative to Webster's equations is presented by Dr. Earl Geddes:
- Earl Geddes, Acoustic Waveguide Theory, AES Journal Vol. 37, Number 7 pp. 554 (1989)
- Earl Geddes, Author's Reply to "Comments on 'Acoustic Waveguide Theory'", AES Journal Vol. 39, Number 6 pp. 471 (1991)
- Earl Geddes, Acoustic Waveguide Theory Revisited, AES Journal Vol. 41, Number 6 pp. 452 (1993)
- Earl Geddes et al., Acoustic Waveguides-In Practice, AES Journal Vol. 41, Number 6 pp. 462 (1993)
More References
1. "Design Factors in Horn-Type Speakers" Daniel J. Plach, 3 pp (6 pp in
journal) (Journal of Audio Engineering Society -- JAES), Vol. 1, No. 4,
October 1953)
2. "High-Efficiency Three-Way Speaker System" S.J. White, Journal of
Audio Engineering Society (JAES) , July 1955, Vol. 3, No. 3, pp.
155-159.
3. "Acoustical Studies of the Tractrix Horn. I" and "Acoustical Studies
of the Tractrix Horn,. II" Robert F. Lambert, 10 pp. (JASA, Vol. 26, No.
6, November 1954)
comment: Early and significant work in the prediction of throat
impedance characteristics is presented, what makes this paper even
more interesting is that the horn is a large axisymmetrical tractrix,
in experiments driven by a WE 555W driver. Interesting, hard to find
information about tractrix horns.
4. "Horn Loudspeakers", Chapter 7, from "Elements of Acoustical
Engineering" Harry F. Olson, 17 pp. (34 pages in original book) - 1957
comment: Nice treatment of general horn theory with many graphs,
drawings and even practical considerations and examples. Nice!!
5. "Development of Horn-Type Moving Coil Driver Unit", J.K. Hilliard,
JAES, Vol. 14, No. 4, 1966, pp. 252-xxx.
6. "360 degree Conical Wavefront Loudspeaker for the New York World's
Fair", J.E. Volkmann,, A.R. Morgan, and H.F. Olson, JAES, Vol. 16, No.
2, 1968, pp. 130-xxx.
7. "One Kilowatt Cylindrical Wavefront Loudspeaker for the New York
World's Fair", J.E. Volkmann, JAES, Vol. 16, No. 2, 1968, pp. 136-xxx.
8. "Horn-Loaded Electrostatic Loudspeaker", J. Merhaut, JAES, Vol. 19,
No. 10, 1971, pp. 840-xxx.
9. "Acoustical Impedance, and the Theory of Horns and of the
Phonograph", A.G. Webster,
JAES, Jan/Feb 1977, Vol. 25, No. 1/2, pp. 24-28. (Reprint of 1919
article)
10. "Discussion: The Function and Design of Horns For Loudspeakers",
JAES, Mar 1978, Vol. 26, No. 3, pp. 131-138. (Reprint of 1924 article)
"A High-Efficiency Receiver for a Horn-Type Loudspeaker of Large Power
Capacity", E.C. Wente and A.L. Thuras, JAES, Mar 1978, Vol. 26, No. 3,
pp. 139-nnn. (Reprint of 1928 article)
"A Study of Theatre Loud Speakers and the Resultant Development of the
Shearer Two-Way Horn System", J.K. Hilliard, JAES, Nov 1978, Vol. 26,
No. 11, pp. 843-850. (Reprint of 1936 article)
"The Manta-Ray Horns" Clifford A. Henricksen and Mark S. Ureda (JAES,
Vol. 26, No. 9, September 1978)
comment: The paper deals with the theoretical basis for Altec Lansing's
Manta-Ray type of constant directivity horns.
"Historical review of horns used for audience-type sound reproduction",
J.K. Hilliard, Journal of Acoustic Society of America., Vol. 59, No. 1,
Jan 1976, pp. 1-8.
"An efficiency constant comparison between low-frequency horns and
direct-radiators", D.B. Keele, Jr., Audio Engineering Ssociety (AES)
Preprint 1127, 54th Convention, May 4-7 1976. -- Note: AES Preprints are
material from AES conventions.
54. "A Study of Theatre Loud Speakers and the Resultant Development of
the Shearer Two-Way Horn System" John K. Hilliard, 8 pp. and "Dividing
Networks for Loud Speaker Systems" John K. Hilliard, H.R. Kimball, 6 pp.
(JAES, Vol. 26, No. 11, November 1978 - reprinted from Academy Research
Council Technical Bulletin, 1936 Volume, March 3, 1936 pp. 1-28)
comment: Historically and technically very interesting paper about this
big Shearer/MGM theatre horn system whose development involved greats
like Harry F. Olson and James B. Lansing. Great!
"A New Piezoelectric Driver Enhances Horn Performance", J.R. Bost, JAES,
1980 April, Vol. 28, No. 4, pp. 244-249.
"Acoustic Radiation of a Horn Loudspeaker by the Finite Element Method -
Acoustic Characteristics of a Horn Loudspeaker with an Elastic
Diaphragm", N. Kyounu, S. Sakai, S. Morita, T. Yamabuchi, and Y. Kagawa,
-- JAES, Vol. 30, No. 12, 1982 Dec, pp. 896-905.
"The Boundary Element Method and Horn Design", D.J. Henwood, -- JAES,
Vol. 41, No. 6, 1993 Jun, pp. 485-496.
"On the Specification of Moving-Coil Drivers for Low-Frequency
Horn-Loaded Loudspeakers" W. Marshall Leach, jr., 6 pp (12 pp in
journal) (JAES, Vol. 27, No. 12, December 1979)
comment: (from header of the paper): "A procedure is described for the
design from specifications of moving-coil drivers for low-frequency
horn-loaded loudspeakers. The method permits specification of the upper
and lower cutoff frequencies, the volume of the cavity behind the
driver, the driver area, the horn throat area, and the desired system
electrical impedance. From these specifications, the required
Thiele-Small small-signal parameters of the driver are determined under
the condition of a maximum-sensitivity constraint on the system. The
procedure can be easily modified for a maximum-efficiency constraint."
"Every One-Parameter Acoustic Field Obeys Webster's Horn Equation", G.R.
Putland, -- JAES, Vol. 41, No. 6, 1993, pp. 435-xxx.
"Acoustic Waveguide Theory Revisited", E.R. Geddes, -- JAES, Vol. 41,
No. 6, 1993, pp. 452-xxx.
"Acoustic Waveguides - In Practice", P.D. Bauman, A.B. Adamson, & E.R.
Geddes, -- JAES, Vol. 41, No. 6, 1993, pp. 462-xxx.
"Measurement of Input Impedance of Loudspeaker Horns", T. Salava, --
JAES, Vol. 29, No.6, 1981, pp. 416-xxx.
"Impulse Measurement of Horn-Type Loudspeaker Drivers", J. Merhaut, --
JAES, Vol. 34, No. 4, 1986, pp. 245-xxx.
More on "Impulse Measurement of Horn-Type Loudspeaker Drivers", J.
Merhaut, -- JAES, Vol. 35, No. 3, 1987, pp. 144-xxx.
Letters to the Editor: Comments on "Horn Modelling with Conical and
Cylindrical Transmission Line Elements", J.T. Post and E.L. Hixson
(including author's reply), -- JAES, Vol. 42, No. 6, 1994 June, pp.
497-498.
"Equivalent circuits for conical waveguides", A.H. Benade, -- J. Acoust.
Soc. Am, Vol. 83, No. 5, May 1988, pp. 1764-1769.
"Apparent apex part II: the three dimensional case", M. Ureda, -- AES
Preprint 3040, 90th Convention, Feb 19-22, 1991.
"Tractrix Horns: Improved Imaging and Phasing", R. Delgado, K. Geist,
and J. Hunter, -- Audio, March 1991, pp. 36-40.
"Horn Modelling with Conical and Cylindrical Transmission Line
Elements", D. Mapes-Riordan, -- AES Preprint 3194, 91st Convention, Oct
4-8, 1991.
"Apparent apex part III: the three dimensional case", M. Ureda, -- AES
Preprint 3166, 91st Convention, Oct 4-8, 1991.
"Modeling of the Nonlinear Behaviour of a Horn Loaded Compression Driver
System", R. Schmitt and W. Klippel, -- AES Preprint 3256, 92nd
Convention, Mar 24-27, 1992.
"Impulse Meaasurement of Acoustic Impedance of Horns", P. Pribyl and D.
Holan, -- AES Preprint 3270, 92nd Convention, Mar 24-27, 1992.
"A Computational Model of Horn Loudspeakers", J. Backman, -- AES
Preprint 3512, 94th Convention, Mar 16-19, 1993.
"Directivity Phase Response of Horns", M.S. Ureda, -- AES Preprint 3593,
94th Convention, Mar 16-19, 1993.
"Round the horn", P. Newell, -- Studio Sound, March 1994, pp. 59-nnn.
"The Convolution Method for Horn Array Directivity Prediction", M.S.
Ureda, -- AES Preprint 3790, 96th Convention, Feb 26-Mar 1, 1994.
"Beam Width Change of Transducer Array Directional Patterns", D. Ruser,
-- AES Preprint 3829, 96th Convention, Feb 26-Mar 1, 1994.
"A loudspeaker horn that covers a flat recatngular area from an oblique
angle", D.B. Keele, Jr., -- AES Preprint 2052, 74th Convention, Oct 8-12
1983.
"Horn layout simplified", B. Thurmond, -- AES Preprint 2167, 76th
Convention, Oct 8-11 1984.
"Wide dispersion frequency invariant acoustic lens", M.W. Ferralli and
J. White, -- AES Preprint 2267, 79th Convention, Oct 12-16 1985.
"Computer Simulation of Horn Loaded Compression Drivers", E. Geddes and
D. Clark, -- AES Preprint 2286, 79th Convention, Oct 12-16 1985.
"Spruce moose: a slightly bent horn", E.J. Czerwinski, M.D. Buck, and A.
Duncan, -- AES Preprint 2311, 79th Convention, Oct 12-16 1985.
"Optimization procedure for computer designing a horn loudspeaker", --
M.A. Milosevic and M.V. G Mitrovic, AES Preprint 2360, 79th Convention,
Oct 12-16 1985.
"An omnidirectional sound source", P. Lunden, -- AES Preprint 2431, 82nd
Convention, Mar 10-13 1987.
"Horn speaker having continuously changing cross section", M. Ohkawa and
H. Yoshii, -- AES Preprint 2664, 2nd Regional Convention, Tokyo, Jun
17-19 1987.
"Horn Loading Revisited", R.M. Harris, -- Elektor in Australian
Electronics Monthly, Oct 1987, pp. 38-44.
"Acoustic waveguide theory", E.R. Geddes,-- AES Preprint 2547, 83rd
Convention, Oct 16-19 1987.
"General equivalent electrical circuits for acoustic horns", J.
Kergomard, -- AES Preprint 2575, 84th Convention, Mar 1-4 1988.
"A new look at horn speakers", A. Orlowski, -- Hi-Fi News & Record
Review, Jan 1983, pp. 39-43.
"Loudspeaker Acoustics - Horn Design", Electronics, June 1941, pp. 58.
"Horn-Type Electrothermal Loudspeakers", T.S. Paige, M.A.K. Hamid, IEEE
Trans. on Audio and Electroacoustics, Vol. AU-20, No. 3, Aug 1972, pp.
218-222.
"Letters to the Editor - Horn Loudspeaker Design", T. Hevreng and J.
Dinsdale's reply,
Wireless World, Jun 1974, pp. 180.
"Letters to the Editor - Horn Loudspeaker Design", J. Dinsdale, Wireless
World, May 1982, pp. 60.
More References:
(Comments by Tom)
"The Function and Design of Horns for Loudspeakers" C.R. Hanna and J.
Slepian, 13 pp. (JAES reprint, original article first presented in 1924
by AIEE)
comment: Thorough treatment of conical, exponential and hyperbolical
horns with lots of math, including some analogies/models from the
electronic world.
"Discussion: The Function and Design of Horns for Loudspeakers" H.
Fletcher, V. Karapetoff, S. Boyajian, A. Nyman, E.W. Kellogg, L.P.
Rundle, J. Minton, J. Slepian, 9 pp. (JAES reprint, original article
first presented in 1924 by AIEE)
comment: Comments, discussion and critique of the preceding paper. Given
the age of these papers, some will be old news, but they are of great
historical interest and of general interest to any horn builder.
"A High-Efficiency Receiver for a Horn-Type Loudspeaker of Large< Power
capacity" E.C. Wente and A.L Thuras, 6 pp. (JAES reprint, original
article from Bell System Technical Journal, 1928)
comment: Witness the invention of the compression horn driver as we know
it. These guys designed the Western Electric 555 and 594 drivers!
Describes first generation of compression drivers, with field coils,
phase plug, edge wound aluminum ribbon voice coils and aluminum
diaphragms. Great stuff!
Bunch of Celestion and Electro-Voice PA bass horn drawings, 11 pp.
comment:
Big beasts, get a new house if you plan to use any of these at home.
Some could possibly be shrunk a little and adapted for other uses than
big scale PA. Cool designs, though.
"A Back-Loaded Wall-Horn Speaker" Rick Steiner, 12 pp. (Speaker Builder
4/91)
comment: Kind of interesting, with a clever horn mouth that takes
advantage of the floor, but not a very flexible design, as midrange and
tweeter are mounted into the front of the bass horn enclosure. Uses
Speakerlab mid and tweet horns and Oaktron 15" woofer. Big speakers that
appear to play reasonably deep bass.
"The Show Horn" Bruce Edgar, 12 pp. (Speaker Builder, 2/90)
comment: Big, 50 Hz hypex bass horn with folding inspired by old
University design. Probably great if you have the space. Uses EV EVM12L
driver.
"Solving the Klipschorn Throat Riddle" Bruce Edgar, 4pp. (Speaker
Builder 4/90)
comment: Theoretical analysis of the constricted throat geometry used in
the Klipschorn. Gives clues as to how the technique can be used to
accomodate for a wider choice of woofers to be used in a bass horn.
"Vintage Designs: University Classic" Courtesy of B.Edgar, 1 page.
(Speaker Builder 2/90)
comment: Large bass horn...the folding used in this horn inspired Edgar
when he designed the Show Horn. Horn has room to fit midrange and
tweeter horns inside the bass horn mouth.
"A Low Frequency Horn of Small Dimensions" Paul W. Klipsch, 8 pp. (JASA,
Vol. 13 October 1941)
comment: The first paper on the classical Klipschorn (corner bass horn).
Some curves and a lot of enthusiastic talk about how good the horns
sound.
"Improved Low-Frequency Horn" Paul W. Klipsch, 4 pp. (JASA, Vol. 14
January 1943)
comment: Followup to previous article, better measurements and some
improvements in the design of the horn.
"A High Quality Loudspeaker of Small Dimensions" Paul W. Klipsch, 6 pp.
(JASA, Vol. 17 No.3 January 1946)
comment: Complete system using the corner bass horn and HF horn using
WE 555W driver is described, along with evaluations. If you own a KHorn,
all these articles should be useful.
"Generalized Plane Wave Horn Theory" Vincent Salmon, 13 pp. (JASA, Vol.
17 No.3 January 1946)
comment: A theoretical treatment of horns, with mathematical and
electrical models/analogies. Lotsa math, not a lot of immediate
practical interest.
"A New Family of Horns" Vincent Salmon, 7 pp. (JASA, Vol. 17 No.3
January 1946)
comment: Introduction of the (then) new hyperbolic-exponential horns,
along with a number of graphs and mathematical explanations.
"Horn Loudspeaker Design" Parts 1-3 Jack Dinsdale, 17 pp. (Wireless
World, March, May and June 1974)
comment: Essential horn basics written by a horn enthusiast with a
practical approach to things, meant to inspire the amateur builder.
Great, great article that covers different horn flares, including the
tractrix. The last article finishes off with two practical designs, one
of which is a huge tractrix bass horn. Excellent, lots of useful curves,
tables and explanations that normal people can understand. Many good
literature references worth checking out (many are on my list already).
"Low-cost Horn Loudspeaker System" "Toneburst", 4 pp.(Wireless World,
May 1970)
comment: Large, Klipsch-style split bass horn with HF horn on top.
Pictures and drawings seem frustratingly cryptical to be followed
directly by a builder, but the design seems interesting nevertheless. If
nothing else, at least for inspiration.
"Tractrix Horn Theory" Andy Grove, 2 pp. (HiFi World Supplement,
November 1994)
comment: It Stinks! I could have done better myself! Forget it!
Catalog of Lowther Club Danmark (Denmark) H.J. Loenborg, 12 pp.
comment: Short summary of Voigt's work on horns and driver design along
with practical application details. Many interesting pictures. Specs
and prices of the whole range of Lowther drive units and a short
overview of different folded horn designs, complete plans of which can
be ordered from the club. Whole thing in Danish...
Chapter 9 - "Horn Loudspeakers" from "Acoustics" L.L. Beranek 1954, 14
pp. (27 pages in original book)
comment: A lot like Olson's treatment of horn speakers, essential basic
theory with some drawings, graphs and other nice things. Some practical
examples here as well.
Sections 5.17 through 5.30 from "Elements of Acoustical Engineering"
H.F. Olson, 8 pp. (16 pages in original book)
comment: Mathematical treatment of impedance and other characteristics
of different horn flare types, also shows effect of truncating horns on
impedance plot and some other interesting things.
Sections 2.19-2.20 from "Elements of Acoustical Engineering" H.F. Olson,
4 pp. (7 pages in original book)
comment: Great, VERY useful polar diagrams that show
dispersion/directivity patterns of many different horns for fixed or
varying flare rate or mouth size. Nice.
"Loudspeaker Performance" Paul W. Klipsch, 3 pp. (Wireless World,
February 1970)
comment: Enthusiastic horn propaganda from Klipsch himself. If there's
any doubt, this article tells you why horns are it! Fun to read.
Makes most modern speakers seem crude and awkward. Interesting and
important comparison of distortion in horn vs. direct radiator speaker.
"Design For A Folded Corner Horn" H.J.F. Crabbe (Wireless World,
February 1958)
comment: A very strange and exotic looking corner horn said to have a
response down to 40 Hz. Looks like a nightmare to build, but the
complete unit looks like something out of a 1950s sci-fi movie, pretty
cool. Appears to utilize some sort of Lowther driver. has midrange horn
on front of driver and rear loaded bass horn on the other side.
Plan: "Lowther Acousta 124" Lowther Loudspeaker Co.
comment: Folded rear loaded horn for two 8" drivers (can't tell which)
for full range no xover operation.
Plan: "Lowther Classic 400" Lowther Loudspeaker Co.
comment: Another folded rear loaded horn (full range) for one 8" driver
(I think).
Plan: "Lowther Acousta 109" Lowther Loudspeaker Co.
comment: Yet another rear loaded folded full range horn for one 8"
driver.
Plan: "Lowther Acousta 115" Lowther Loudspeaker Co.
comment: Still one more rear loaded folded horn, like the Acousta 109,
only bigger.
Chapter 11 - "Horn-Type Enclosures" from "Hi-Fi Loudspeakers and
Enclosures" 2nd. edition. A. Cohen, 14 pp. (28 pages in original book)
comment: Great explanation and intro to horns with little math and down
to earth approaches. Many examples and an enthusiastic tone (pro
horns!). Get the entire book if you can.
"Horns" from "High Quality Sound Reproduction" James Moir, 12 pp (23
pages in original book)
comment: Nice general, reasonably light explanation of horns with some
cool pictures and drawings of practical designs. The rest of the book
is excellent, too. Look for it at the library.
Chapter 12 - "Combined Enclosure-Horn System" from "Hi-Fi Loudspeakers
and Enclosures" 2nd. edition. A. Cohen, 5 pp (was 10 pages in original
book).
comment: Brief explanations of how it's possible to horn load reflex
ports and build VOT style cabinets that combine horn loading and reflex
loading. Not really crucial.
"Hoeyjttaler-selvbyg bogen" Audioscan, 1982.
comment: Essentially a catalog of Coral full range and horn/compression
drivers along with general speaker theory and many designs using Coral
drivers, a couple of VOT-style brutes, too. Read it and cry 'cause Coral
is no longer in business. Some theory, too. Only interesting to
scandinavians I guess, since it's all in Danish. Has specs for all the
Coral drivers available back then. (High efficiency full range & horn
drivers).
"1st Book of Hi-Fi Loudspeaker Enclosures" B.B. Babani, 48 pp. (96 pages
original book)
comment: A collection of speaker enclosure designs, some worthless but
some interesting ones, including a few Altec designs and the old
Karlson bass speaker. Very sparse details and descriptions, but lots of
inspirational drawings.
"Ton-and-a-Quarter of Sound" Walter Wysoczanski, 5 pp. (8 pages orig.
article, Audio, January 1964)
comment: WOW!!! Huge, cast concrete full range horn system with front
loaded bass horns that use two 15" woofers each. Concrete HF horn for
Altec 288 compression driver.
"Wide-Angle Dispersion of High-Frequency Sound" A.B.Cohen, 5 pp. (Audio
Engineering, December 1952)
comment: Excellent discussion of dispersion in HF horns of different
types and how it can be optimized. With curves, sketches and Cohen's
comprehensive way to explain things. Great!
"A New Loudspeaker of Advanced Design" Daniel J. Plach and Philip B.
Williams, 4 pp. (Audio Engineering, October 1950)
comment: Description and evaluation of the Jensen G-610 Triaxial
loudspeaker that has horn loaded midrange and tweeter. Extremely cool
looking driver. Very enthusiastically written by two of the
co-developers of the speaker. Interesting.
"A Loudspeaker for the Range from 5 to 20 kc" B.H. Smith and W.T.
Selsted (Audio Engineering, January 1950)
comment: Interesting article describing a HF horn system with two horn
loaded drivers. These horns are of the flat, "circle sector" type,
good descriptions of which are seldom found in horn literature. These
have some interesting properties worth looking into, particularly
dispersion. Another plus is that they're very easy to build compared to
most other horn types.
Section 4.4. - "Horns" Rossi, 7 pp. (12 pages in original book)
("Acoustics and Electroacoustics")
comment: Presents the different main families of horns, in a
mathematical way, with lots of differential equations and other apalling
stuff. Might still be useful.
Section 7.4 - "Horn Loudspeakers" Rossi, 7pp. (12 pages in original
book, Acoustics and Electroacoustics)
comment: Brief intro to horn loudspeakers, with discussion of
efficiency, frequency response, distortion. Theoretical, with some
analogies (electrical equivalents). Nothing major.
"The Edgar Midrange Horn" Bruce C. Edgar, 11 pp. (Speaker Builder, 1/86)
comment: The original article about the Edgar midrange tractrix horn, of
general interest to anyone building midrange horns, but has very
detailed costruction details - a must if you plan to build the standard
midrange horn. Great!
"The Klipschorn Throat Revisited: Or, Oooops" Bruce C. Edgar, 2 pp.
(Speaker Builder, 6/90)
comment: Corrections and additions to the article called "Solving The
Klipschorn< Throat Riddle" (SB 4/90). Don't read one without reading
the other.
"Round The Horn" Philip Newell and Keith Holland, 8pp. (Speaker
Builder, 8/94)
comment: Very interesting article on midrange horns, particularly
circular horns. Many measurements and references to a very thorough
5-year study. Should be of interest to any horn builder.
"The Monolith Horn" Bruce C. Edgar, 7 pp. (Speaker Builder, 6/93)
comment: Edgar's imposing 40 Hz bass horn, complete with measurements,
drawings, photos of construction details. Cool stuff!
"Chapter Five: Theory of Horns" J. Merhaut, 13 pp. (26 pp. in book)
("Theory of Electroacoustics")
comment: Basic theory on wave propagation, dense math. Covers
exponential, conical and hyperbolical horns. Not very pragmatic, but
theoretically thorough.
"Prediction and Measurement of the One-Parameter Behavior of Horns" K.R.
Holland, F.J Fahy, and C.L. Morfey, 23 pp. (JAES, Vol. 39, No. 5, May
1991)
comment: (from the header of the paper): "It is investigated to what
extent aspects of the performance of horns can be modeled using
Webster's one-parameter horn equation. A computer model, based on
Webster's equation, is described. Its results are compared to
measurements. It is shown that a one- parameter horn model can
accurately predict throat impedance provided that the shapes of the
wavefronts are taken into account."
"Chapter 4 - Radiation of Sound" L.L. Beranek, 13 pp. (26 pp. in book)
("Acoustics")
comment: Good treatment of dispersion of sound from different sources,
including examples of different horn types, with polar diagrams.
comment: The paper mainly deals with the improvement of low frequency
cutoff characteristics made possible by using reactance annulling in
hypex (hyperbolical-exponential) horns. Of special interest with regard
to bass horn design.
"Sound Translating Device" E.C. Wente, 5 pp. (US Patent No.
2,037,187.ril 14, 1936)
comment: This is the patent for the compression driver that came to be
manufactured under the name "Western Electric 594A", and basically this
driver has all the ingredients of compression drivers made today, the
only difference being the magnetic circuit. In modern drivers permanent
magnets are used instead of field coil magnets, but apart from that the
594A driver is as "modern" as any. Compare to a JBL 2445 and see how
refined this 60+ year old driver was!
"Dem Bass auf die Sprunge geholfen (Hornlautsprecher fuer den
Tieftonbereich Teil 2)" Bernd Timmermans, 2 pp. (Klang & Ton 4/91)
comment: Very brief and basic horn theory (how much can one cover on 2
pages?). In German.
"Reconsider, baby - The promise of horns in the contemporary situation"
Joe Roberts, 4 pp. (Sound Practices, Fall 1994)
comment: Discussion of the horn and triode amplifier reneissance, in a
context of tradition, history and trends. Written by Joe Roberts,
enjoyable as always.
"Casual Reactions" Herb Reichert, 5 pp (Sound Practices, Spring 1994)
comment: Description of Edgar Horn systems, and the BLISS (Blue Island
Sound System) with photos and sketches. Enthusiastic and insightful as
always with Herb's articles.
"What About Horns?" Greg Boynton, 4 pp. (Sound Practices #1, Vol. 1,
Summer 1992)
comment: Good advice, dos and don'ts for anyone trying to collect parts
for a home horn system with special attention paid to Altec VOT
speakers. Good, healthy horn propaganda.
"The Tractrix Horn Contour" Bruce Edgar, 6 pp. (Speaker Builder, 2/81)
comment: Very good introduction to tractrix horns, with interesting
historical information about Voigt's work. Useful graphs and charts
for tractrix design. Many further references given.
Another Set of References
Courtesy of horn fanatic Bill Geiger (taken from GM's post on
the Full Range Driver Forum).
L.F. Horn Design & Driver Parameters
[001] Title: Design Factors in Horn-Type Speakers
Publication: AES-J, Vol. 1, No. 4, pp. 276 (1953)
Author: Daniel J. Plach
Abstract: Maximum efficiency in a horn unit can be
achieved only if a conjugate match exists between
driver and horn. This match is possible only if the
unloaded resonance of the driver is greater than horn
cutoff frequency. Since the throat resistance of a
finite
[002] Title: On the Specification of Moving-Coil
Drivers for Low-Frequency Horn-Loaded Loudspeakers
Publication: AES-J, Vol. 27, No. 12, pp. 950 (1979)
Author: W. Marshall Leach, Jr.
Abstract: A procedure is presented for the design
from specifications of moving-coil drivers for
low-frequency horn-loaded loudspeakers. The method
permits specification of the upper and lower system
cutoff frequencies, the volume of the cavity behind
the driver,
[003] Title: Comments on Reactance Annulling in
Horn-Loaded Loudspeaker Systems
Publication: AES-J, Vol. 29, No. 7, pp. 523 (1981)
Author: Edward F. McClain, Jr.
[004] Title: Author's Reply to "Comments on Reactance
Annulling in Horn-Loaded Loudspeaker Systems"
Publication: AES-J, Vol. 29, No. 7, pp. 523 (1981)
Author: W. Marshall Leach, Jr.
[005] Title: Optimum Horn Mouth Size
Publication: AES-P, No. 933, Cnv. 46 (1973-09)
Author: D. B. Keele, Jr.
Abstract: Loudspeaker exponential horn computer model
studies indicate that there is an optimum mouth size
for a horn of specific cutoff to minimize mouth
reflections. Evaluation of the reflection coefficient
at the horn's mouth reveals how large the mouth must
be
[006] Title: Low-Frequency Horn Design Using
Thiele/Small Driver Parameters
Publication: AES-P, No. 1250, Cnv. 57 (1977-05)
Author: D. B. Keele, Jr.
Abstract: The design formulas for low-frequency horns
which yield various physical and performance related
horn data can be recast in a form which utilizes the
Thiele/Small direct-radiator driver parameters. This
conversion simplifies computations of items such a
[007] Title: Suitability of Low-Frequency Drivers for
Horn-Loaded Loudspeaker Systems
Publication: AES-P, No. 1251, Cnv. 57, (1977-05)
Author: Richard H. Small
Abstract: The efficiency, bandwidth and power
capacity of low-frequency horn-loaded loudspeaker
systems are directly affected by the parameters of
the driver used. Three new composite driver
parameters, formed by simple combination of the basic
parameters, give a
[008] Title: A Two-Port Analogous Circuit and SPICE
Model for Salmon's Family of Acoustic Horns
Publication: ASA-J, Vol. 99 No. 3, pp. 1459-1464
(Mar-1996)
Author: W. Marshall Leach, Jr.
Abstract: A two-port electroacoustic analogous
circuit model for finite-length acoustic horns
belonging to Salmon's family of horns is described.
An implementation of the circuit model for use with
the PSpice simulator software is given.
Internet:
M. Leach Papers
[009] Title: Simplified Loudspeaker Measurements at
Low Frequencies
Publication: AES-J, Vol. 20, No. 1, pp. 28 (1972)
Author: Richard H. Small
Abstract: The effective free-field frequency response
and harmonic distortion of a direct-radiator
loudspeaker system can be measured at low frequencies
without establishing free-field radiation conditions.
The technique is based on measurement of the
acoustical p
[010] Title: Direct Radiator Loudspeaker System
Analysis
Publication: AES-J, Vol. 20, No. 5, pp. 383 (1972)
Author: Richard H. Small
Abstract: The low-frequency performance of
direct-radiator loudspeaker systems can be accurately
specified and is quantitatively related to the basic
parameters of the system components. These systems
function at low frequencies as low-efficiency
electroacoustic
[011] Title: Direct Low-Frequency Driver Synthesis
from System Specifications
Publication: AES-J, Vol. 30, No. 11, pp. 800 (1982)
Author: D.B. Keele, Jr.
Abstract: The usual procedure for direct-radiator
low-frequency loudspeaker system design leads to the
calculation of the driver's fundamental
electromechanical parameters by an intermediate
specification of the Thiele-Small parameters. A
reformulation of the syn
[012] Title: Comments on "Direct Low-Frequency Driver
Synthesis from System Specifications"
Publication: AES-F, Vol. 32, No. 7, pp. 543 (1984)
Author: Thomas L. Clarke
H.F. Horn and Phase Plug Design
[013] Title: Phase Plug Modelling and Analysis:
Circumferential Versus Radial Types
Publication: AES-P, No. 1140, Cnv. 55 (1976-10)
Author: Clifford A. Henricksen
Abstract: Mechanical modeling of a simple phase plug
yields an electrical-mobility equivalent circuit; a
single-frequency notch filter. This applies directly
to "normal" circumferential-slit configurations. The
analysis is then applied to a radial-slit phase plug,
[014] Title: Phase Plug Modeling and Analysis: Radial
Versus Circumferential Types
Publication: AES-P, No. 1328, Cnv. 59 ( 1978-02)
Author: C. A. Henricksen
Abstract: Mechanical modeling of a simple
two-dimensional phase plug and diaphragm yields an
electrical mobility equivalent circuit; a two-pole,
low-pass filter. At higher frequencies, this analysis
becomes incomplete, and a model presented by Merhaut
(1975) is us
[015] Title: An Application of Bob Smith's Phasing
Plug
Publication: AES-P, No. 1384, Cnv. 61 (1978-11)
Author: F. M. Murray
Abstract: The war of the phasing plugs still rages
after more than 25 years. Compression driver phasing
plugs have vacillated between annular rings, salt
shakers, teardrops, and now radial slots again. When
Bob Smith provided simple design criteria for
[016] Title: The Dual Coil Inductively Coupled
Loudspeaker System Performance Optimization and the
Application of an Acoustic Phase Correction Plug
Publication: AES-P, No. 2780, Cnv. 86 ( 1989-03)
Author: Boaz Elieli
Abstract: Analysis of the dual coil inductively
coupled loudspeaker system using an electrical
equivalent circuit is presented, and some of the
practical design aspects relating to the system
optimization are discussed. The application of an
acoustic phase correct
[017] Title: Ultimate Performance of Wide-Range
High-Frequency Compression Drivers
Publication: AES-J, Vol. 24, No. 8, pp. 639 (1976)
Author: Clifford A. Henricksen
Abstract: Performance equations are developed from an
electric mobility model of a typical electromagnetic
compression driver. The analysis is independent of
impedance and relates ultimate performance to
material, air, and phase-plug variables.
[018] Title: An Investigation of the Air Chamber of
Horn Type Loudspeakers
Publication: ASA-J, Vol. 25, No. 2, Pg. 305-312,
Mar-1953
Author: Bob H. Smith
Abstract: The front air chamber design is treated as
a boundary value problem which yields a solution of
the wave equation for the general case in which the
horn throat enters the air chamber in a
circumferentially symmetrical manner.
[020] Title: Acoustical Studies of the Tractrix Horn.
I
Publication: ASA-J, Vol. 26, No. 6, Pg. 1024-1033,
Nov-1954
Author: Robert F. Lambert
Abstract: Acoustical properties of the tractrix horn
are modeled, measured and compared in a two part
article.
[021] Title: Acoustical Studies of the Tractrix Horn.
II
Publication: ASA-J, Vol. 26, No. 6, p.1024-1033,
Nov-1954
Author: Robert F. Lambert
Abstract: Acoustical properties of the tractrix horn
are modeled, measured and compared in a two part
article.
[022] Title: Theater Loudspeaker System Incorporating
an Acoustic-Lens Radiator
Publication: SMPTE-J, Vol. 63, p. 82, Sep-1954
Author: John G. Frayne
Author: Bart N. Locanthi
Abstract: This paper describes a two-way loudspeaker
system for presentation of stereophonic sound in
motion-picture theaters. The systems presented use
divergent acoustic lenses to achieve a wide
dispersion pattern for high frequencies.
[023] Title: Refracting Sound Waves
Publication: ASA-J, Vol. 21, No. 21, p. 471, Sep-1949
Author: Winston E. Kock
Author: F.K. Harvey
Abstract: Structures that refract and focus sound
waves are described. These include path length delay
element and obstacle arrays that function as the
acoustical convergent and divergent lenses.
[024] Title: A Modeling and Measurement Study of
Acoustic Horns
Author: Post, John Theodore
Publication: Thesis (Ph.D.)--The University Of Texas
at Austin, 1994. Source: Dissertation Abstracts
International, Vol. 55-06, Sec. B, Pg. 2246, UMI Co.
Abstract: Although acoustic horns have been in use
for thousands of years, formal horn design only began
approximately 80 years ago with the pioneering effort
of A. G. Webster. In this dissertation, the
improvements to Webster's original horn model are
reviewed and the lack of analytical progress since
Webster is noted. In an attempt to augment the
traditional methods of analysis, a semi-analytical
technique presented by Rayleigh is extended. Although
Rayleigh's method is not based on one-dimensional
wave
[025] Title: A theoretical and experimental
investigation of the throat impedance characteristics
of constant directivity horns
Publication: ASA-J, Vol 92, No. 5, Nov-92, p.
2509-2520
Author: McLean, James S.
Author: Post, John T.
Author: Hixson, Elmer L.
Abstract: none
URL:
A theoretical and experimental investigation of the throat impedance characteristics of constant directivity horns
[026] Title: Rayleigh's horn equation
Publication: ASA-J, Vol. 94, No. 3, Sep-1993, p.1803
Author: Post, John T.
Author: Hixson, Elmer L.
Abstract: none
URL:
Rayleigh's horn equation
[027] Title: Measurement of throat impedance and
far-field directivity for acoustic horns
Publication: ASA-J, Vol. 96, No. 5, Nov-94, p. 3290
Author: Post, John T.
Author: Hixson, Elmer L.
Abstract: none
URL:
Measurement of throat impedance and far-field directivity for acoustic horns
[105] Title: Computer Simulation of Horn-Loaded
Compression Drivers
Publication: AES-J, Vol. 35, No. 7, pp. 556 (1987)
Author: Earl Geddes
Author: David Clark
Abstract: Numerous investigators have performed
analyses of horns and compression drivers. Driver
models have typically used a plane-wave tube or
infinite horn as a termination to avoid the
complexities of finite horns. The present approach
models driver and â?¦
[107] Title: Calculation of Sound Radiation from an
Unbaffled, Rectangular-Cross-Section Horn Loudspeaker
Using Combined Analytical and Boundary-Element
Methods
Publication: AES-J, Vol. 38, No. 5, pp. 340 (1990)
Author: T. Shindo
Author: T. Yoshioka
Author: K. Fukuyama
Abstract: Methods are described for calculating the
sound radiation from an unbaffled,
rectangular-cross-section horn loudspeaker using a
minicomputer. The boundary-element method is used for
smaller horn loudspeakers and, in combination with
the analytical method ...
[109] Title: Prediction and Measurement of the
One-Parameter Behavior of Horns
Publication: AES-J, Vol. 39, No 5, pp. 315 (1991)
Author: K. R. Holland
Author: F. J. Fahy
Author: C. L. Morfey
Abstract: It is investigated to what extent aspects
of the performance of horns can be modeled using
Websterâ?Ts one-parameter horn equation. A computer
model, based on Websterâ?Ts equation, is described.
Its results are compared to measurements. It is shown
that a â?¦
[112] Title: Acoustic Wave-guides, In Practice
Publication: Vol. 41, No. 6, pp. 462 (1993)
Author: Paul D. Bauman
Author: A. B. Adamson
Author: Earl R. Geddes
Abstract: The acoustic wave-guide concept first
introduced in 1987 has gained little understanding
within the industry despite fundamental limitations
inherent in traditional horn theory. To illustrate
the practical feasibility of acoustic wave-guides,
measurements â?¦
The Physics of Musical Instruments, Second Edition
Springer-Verlag, Berlin (1998)
Neville H. Fletcher and Thomas D. Rossing
8.12 Curved Horns, pp. 220-222
Wave Propagation in Strongly Curved Ducts
ASA-J, Vol. 74, pg. 320-332, 1983
D.H. Keefe and A.H. Benade
Acoustical Aspects of Woodwind Instruments
Frits Knuf, Amsterdam, pg. 60
Reprinted by Northern Illinois University Press,
DeKalb, IL 1998
C.J. Nederveen (1969)
Propagation in any horn with flared walls is not 1P;
thus, Webster's equation is only an approximate
solution whose accuracy deteriorates with the flair
angle. Pressure across the isophase surface is not
uniform nor is the phase velocity between these
surfaces. I suspect that vector sum of spreading
velocity and forward propagation total to some "c"
that may be a function of frequency. You must cast
your formula in an orthogonal coordinate system for
the flair formula you are using. At a minimum, a 2p
model should yield better results. At high
frequencies, my conjecture is that sound propagation
follows the caustic in the case of a spiral. If this
were true, the process of transformation would be an
extremely important discovery.
When ever I think about your Cornu, hurricanes,
tornadoes, dust devils and toilet flushes come to
mind, which arouses the suspicion that their may be
an advantage to guiding sound propagation in this
fashion.
Well, enough speculation and on to some more
references regarding horn modeling:
Modeling of Horns and Enclosures for Loudspeakers
(PhD thesis)
Author: Gavin R. Putland
Putland web reference
Acoustics and Signal Processing Techniques for
Physical Modeling of Brass Instruments (Thesis,1999)
David P. Berners
Berners web reference
[013] Title: Phase Plug Modeling and Analysis:
Circumferential Versus Radial Types
Publication: AES-P, No. 1140, Cnv. 55 (1976-10)
Author: Clifford A. Henricksen
Abstract: Mechanical modeling of a simple phase plug
yields an electrical-mobility equivalent circuit; a
single-frequency notch filter. This applies directly
to "normal" circumferential-slit configurations. The
analysis is then applied to a radial-slit phase plug,
URL:
AES Preprint Search
[014] Title: Phase Plug Modeling and Analysis: Radial
Versus Circumferential Types
Publication: AES-P, No. 1328, Cnv. 59 (1978-02)
Author: C. A. Henricksen
Abstract: Mechanical modeling of a simple
two-dimensional phase plug and diaphragm yields an
electrical mobility equivalent circuit; a two-pole,
low-pass filter. At higher frequencies, this analysis
becomes incomplete, and a model presented by Merchant
(1975) is...
URL:
AES Preprint Search
[015] Title: An Application of Bob Smith's Phasing
Plug
Publication: AES-P, No. 1384, Cnv. 61 (1978-11)
Author: F.M. Murray
Abstract: The war of the phasing plugs still rages
after more than 25 years. Compression driver phasing
plugs have vacillated between annular rings,
saltshakers, teardrops, and now radial slots again.
When Bob Smith provided simple design criteria for
URL:
AES Preprint Search
[016] Title: The Dual Coil Inductively Coupled
Loudspeaker System Performance Optimization and the
Application of an Acoustic Phase Correction Plug
Publication: AES-P, No. 2780, Cnv. 86 (1989-03)
Author: Boaz Elieli
Abstract: Analysis of the dual coil inductively
coupled loudspeaker system using an electrical
equivalent circuit is presented, and some of the
practical design aspects relating to the system
optimization are discussed. The application of an
acoustic phase correct
URL:
AES Preprint Search
[017] Title: Ultimate Performance of Wide-Range
High-Frequency Compression Drivers
Publication: AES-J, Vol. 24, No. 8, p. 639 (1976)
Author: Clifford A. Henricksen
Abstract: Performance equations are developed from an
electric mobility model of a typical electromagnetic
compression driver. The analysis is independent of
impedance and relates ultimate performance to
material, air, and phase-plug variables.
URL:
AES Preprint Search
[018] Title: An Investigation of the Air Chamber of
Horn Type Loudspeakers
Publication: ASA-J, Vol. 25, No. 2, p. 305-312,
Mar-1953
Author: Bob H. Smith
Abstract: The front air chamber design is treated as
a boundary value problem, which yields a solution of
the wave equation for the general case in which the
horn throat enters the air chamber in a
circumferentially symmetrical manner.
URL: none
 |
|
