Bart Locanthi

[glen]

I would really like to see a page dedicated to Bart Locanthi on this site.
He's been a seminal influence from JBL (acoustic lenses, LE drivers) to HiFi in general (loudspeaker modelling, and improved amplifier output design).
Something like the Ed May page would be great, even if it's a little abbreviated at first it might spark more interest and draw more info and anecdotes to round out the somewhat fragmented picture of this very influential force in Audio history.

Here's the website his son has up in his memory:

http://www.sabl.com/~bart/bnl2/ (http://www.sabl.com/%7Ebart/bnl2/)

[whgeiger]

G,



Bart's work is still available only at TAD/Pioneer. There, he had a sympathetic audience and a cooperative management got some of his best designs to market.



Regards,



WHG

[tomt]

i'd lik to see a page about bart as well

he may very well be the father of the
modern low frequency loudspeaker

[hector.murray]

that link doesn't work. Can we get an update?

[glen]

that link doesn't work. Can we get an update?

Hi Hectort,

Here's a link that's working for me today:

http://www.aracnet.com/~bart/bnl2/

Glen

[glen]

Bartholomew Nicholas Locanthi II


1919-1994





http://www.aracnet.com/~bart/bnl2/Images/BNL2.GIF











1947 B.S. Physics, Caltech (http://www.caltech.edu/)

1947-1953 Research Associate, Caltech (http://www.caltech.edu/)
1953-1960 Computer Engineering Associates
1960-1970 Vice President, JBL (http://www.jbl.com/)
1975-1986 Vice President, Pioneer (http://www.pioneerusa.com/) North America
1987-1994 President, BNL Research Associates




This is currently posted on his son's website:

http://www.aracnet.com/~bart/bnl2/

[glen]

Wit and Wisdom of Bart N. Locanthi II

"There's no such thing as a small change"




I'm pretty sure he invented this one. The thought behind it should be familiar to any engineer. We all like tweaking things after they're "done" - but how often a seemingly harmless adjustment winds up breaking the whole kabosh!




"Use your eyes if you've got 'em"




My father and I shared a disease I call inverse kleptomania. That is, a penchant for leaving things in random places - the more important a thing, the more random the place. While this saying was usually uttered at the most annoying time possible, the sentiment reflects the frustration one develops after a lifetime of suffering from this debilitating condition.




"How about putting a little light on the subject?"




My sister Carol and I were pressed into service as helpers for numerous auto- and aero-motive projects, usually involving tight, poorly lit environments. The entry-level helper's job was to hold a flashlight in such a way as to illuminate the subject in a way useful to the primary worker.




"How about putting a little light on the subject so I can see what the Hell I'm doing?"




Sometimes we didn't get it right the first time. See above.





If you have a saying you can attribute to my father, please let me know!
[email protected] ([email protected])



This is currently posted on his son's website:

http://www.aracnet.com/~bart/bnl2/

[glen]

Partial Publication List


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.

An Ultra-Low Distortion Direct-Current Amplifier
Publication: AES-J, Vol. 15, Number 3, p. 290 (1967)
Author: Bart N. Locanthi
Abstract: A high-power complementary symmetry emitter-follower output amplifier is described which can drive loads in the impedance range of 4 to 16 ohm, providing distortion of less than 0.2% in the range from 20 to 20,000 Hz. Performance measurements on the ...

Application of Electronic Circuit Analogies to Loudspeaker Design Problems
(re-issue of his seminal 1953 paper)
Publication: AES-J, Vol. 19, No. 9, p. 778 (1971)
Author: Bart N. Locanthi
Abstract: Electric circuit analogies are derived for three types of loudspeaker systems: direct radiator in an infinite baffle, direct radiator in a reflex enclosure, and horn loudspeaker. The data are in good agreement with data taken from experimental ...

Rms Power: Fact or Fancy
Publication: AES-J, Vol. 20, No. 1, p. 45 (1972)
Author: John M. Eargle
Author: Bart N. Locanthi

Improved Reed-Solomon Decoding Using Multiple Pass Decoding
Publication: AES-J, Vol. 33, Number 11 p. 878 (1985)
Author: D. Shenton
Author: E. DeBenedictis
Author: B. Locanthi
Abstract: A method is described for improved decoding of Reed-Solomon block data encoded in a cross-interleave Reed-Solomon code (CIRC). Using a new interpretation of the data flow, the encoded data are processed through several identical decoders ...

The Application of Narrow-Band Dither Operating at the Nyquist Frequency in Digital Systems to Provide Improved Signal-to-Noise Ratio over Conventional Dithering
Publication: AES-J, Vol. 35, Number 6 pp. 446 (1987)
Author: Barry A. Blesser
Author: Bart N. Locanthi
Abstract: The application of narrow-band dither operating at the Nyquist frequency to provide improved signal-to-noise ratio performance over conventional dither is discussed, as well as the increased magnitude of narrow-band dither required to be equivalent to ...



This is currently posted on his son's website:
http://www.aracnet.com/~bart/bnl2/

[glen]

Bartholomew Nicholas Locanthi II was born in White Plains, New York, in 1919. Deaf in one ear from a childhood accident, he nevertheless became interested in binaural hearing and sound reproduction, and eventually became one of the leading authorities on loudspeaker design.

His studies at Caltech were interrupted by WWII, and he returned to graduate in physics in 1947. He stayed on as a research associate with an analog computer development group, and became chief engineer of the resultant Computer Engineering Associates from 1953 to 1960.

During this time he published a seminal paper on modeling loudspeaker performance via electrical equivalence circuits. Using analog computers, he first applied this technique to the design of the JBL LE series of transducers, and it has since become the foundation of most loudspeaker computer-aided design programs in use today.

He began consulting for JBL in 1949, and was vice president of engineering from 1960 to 1970. There he developed numerous cone transducers and large format compression drivers, and designed the acoustical lens products that were long a hallmark of the company. He also developed the "T" output circuit that became the standard of transistor amplifiers.

After brief stints at Altec Lansing and Cetec Audio, he joined Pioneer North America in 1975 as vice president of development. Out of this association came the HPM series of consumer loudspeakers and the TAD series of professional drivers.

In the early years of the Compact Disc, he was deeply involved with digital recording, error control, and reproduction, eventually becoming chairman of the AES Technical Committee on Digital Audio. He earned a reputation as "the digital audio police." exposing shoddy algorithms and fighting legislative impairment of digital recordings.

He was AES president 1986-1987, a fellow and member of its board of governors. He was also a fellow of the Acoustical Society of America and a member of the IEEE and SMPTE.

Bart Locanthi died of pancreatic cancer on January 9, 1994.



This is currently posted on his son's website:
http://www.aracnet.com/~bart/bnl2/

[glen]

Transcribed from the Journal of the Audio Engineering Society, Volume 42, Number 3, 1994 March.

http://www.aracnet.com/~bart/bnl2/SPEAKER.GIF

Editor's Note: When the sad news of Bart Locanthi's death reached AES members, many of his longtime friends and colleagues called headquarters. Their voices were filled with sorrow as they recalled the manner of the man and moments they had spent together. They spoke not only of his brilliance, of his being ahead of his time, but of his ability to solve problems, to be a good listener, and to be helpful. "He knew so much that you could bet your seat in heaven what he said was correct," reminisced one of his close friends. The AES grieves the loss of this intellectual, unassuming, and very gentle man.

Bart Locanthi, AES fellow, Silver Medal award winner, and former president of the society, died 1994 January 9 in Glendale, California, after a long bout with cancer. Bartholomew Nicholas Locanthi II was born in White Plains, New York, in 1919. Although his studies at California Institute of Technology were interrupted by the war, he returned there to graduate with a B.S. degree in Physics in 1947. Bart was certainly one of the most versatile audio engineers of his day. His distinguished career spanned the development of analog computers, acoustical transducers, audiophile amplifier design, and digital techniques.

From 1947 to 1953 Bart was associated with an analog computer development group at Cal Tech. It was during this time that he published a seminal paper on modeling loudspeaker performance via electrical equivalent circuits. This paper (later reprinted in the Journal in 1971) has become the foundation of most of the loudspeaker driver/enclosure programs available today.

From 1953 to 1960 he was a partner in Computer Engineering Associates, a company specializing in large scale analog computers and engineering services. In 1949 Bart had begun a long consulting association with William Thomas and James B. Lansing Sound Incorporated, and was later vice president of engineering at JBL from 1960 to 1970. Those of us at JBL are reminded every day of Bart's contribution to the art; such cone transducers as the LE-10, LE-14, and a host of large format compression drivers were all Bart's handiwork, and their progeny are mainstays in the present JBL catalog. He also developed the acoustical lens products, long a hallmark of the company.

It was during the late sixties that Bart developed the "T-Circuit", an output configuration for solid state amplifiers that has become a standard in the industry. Some of the original 20-year-old JBL consumer amplifier models embodying his circuitry now command collector's prices, especially in Japan.

I had first met Bart in New York during the late 60's. It was my pleasure to be a colleague of his at Altec Corporation when I moved to California in 1971. Bart later was associated with Cetec Gauss, a company that manufactured high-quality tape duplicaing products and professional sound components.

In 1975 at the invitation of Takeo Yamamoto, Bart joined Pioneer North America as vice president of development. Out of this association grew the notable HPM series of consumer loudspeakers and TAD series of professional transducers. Bart was also deeply involved in digital development at Pioneer during the early years of the Compact Disc. Bart officially retired from Pioneer in 1986 and formed his own consulting company, BNL Research Associates. Pioneer remained his principal client.

Active in AES affairs, Bart served as papers chairman for conventions, member of the Board of Governors, and as president (1986-1987). His major AES activity in recent years was chairmanship of the technical committee on digital audio. The significant role AES plays today in standards in this vital area is a direct result of Bart's determination and enthusiasm.

His other technical affiliations included membership in the Acoustical Society of America, of which he was a fellow, the Institute of Electrical and Electronics Engineers, and the Society of Motion Picture and Television Engineers. He was also a member of the Hollywood Sapphire Group, an association of audio and recording engineers.

Bart is survived by his widow Dorothy, daughters Carol Wainwright and Jeanne McLaughlin, son Bart III, sister Rose and seven grandchildren.

Among Bart's passions were automobiles and airplanes. He was also a superb teacher. He knew his technology cold and when you approached him with a question, he would not simply give an answer; instead, he would lead you, by example and analogy, to your own answer. This we shall miss most of all.


John Eargle
JME Consulting Corp.





This is currently posted on his son's website:
http://www.aracnet.com/~bart/bnl2/

[glen]

Toys




We have all heard the line that goes, "The difference between men and boys is the cost of their toys."

People who knew my father might have wondered if a more appropriate one would be, "He who dies with the most toys, wins."

My father loved toys, be they mechanical, electronic, or optical. When he made loudspeakers with acoustic lenses, he managed to combine all of these properties. I can imagine him sitting back in his chair at JBL and thinking to himself, "... and they pay me to do this!"

People go through stages in acquiring toys. First, your parents buy them for you. Later, when you start working, you can afford to buy them for yourself. At some point your company starts buying toys - I mean instruments - for you to help you with your work. And when you get really good at it, your company makes toys for you.

My father occupied all positions in the food chain of toys.

When my father broke his back, he failed the triage test - he was too sick to survive an operation to fix it. When the doctor asked what else he could do for him, my father replied, "Send me home."

We knew he didn't want to stay in the hospital - this is where people die, after all. But we feared the transfer would kill him.

It dawned on me that if there was Hell on Earth, this was is it for my father. Having built in his home one of the best sound systems on the planet, here he was stuck in a little room with a small TV and the tinny speaker in the all-purpose bedside control box. So I moved some decent speakers and CD and DAT players into his room and we played music for him in his last days.

I didn't realize until he died why he really wanted to go home. He just wanted to play with his toys.


Bart N. Locanthi, III

January 13, 1994




This is currently posted on his son's website:
http://www.aracnet.com/~bart/bnl2/

[glen]

Photo Gallery


We lived across the street from the Mt. Wilson toll road, and walking the dog meant a 1-3 mile hike through Eaton Canyon or to Henniger Flats. Fred's command of English very definitely included the word "hike", and he was always up for one.


http://www.aracnet.com/~bart/bnl2/HIKE.GIF

"Wanna go for a hike?"













http://www.aracnet.com/~bart/bnl2/ROBE.GIF

Christmas, 1975



This is currently posted on his son's website:
http://www.aracnet.com/~bart/bnl2/

[edgewound]

Glen....

Thanks for taking the time to post all this. JBL & TAD wouln't be what it is without Bart Locanthi.

[spkrman57]

Thanks for posting them!

Ron:)

[alskinner]

There are times when I'm listening to my 2440s and 2441s that I nthink of Bart and smille. Now I just need som TAD 4001s.

AL

[Horn Fanatic]

Not to take anything away from Bart Locanthi, but his design work on acoustic lens' was a product of microwave research conducted by Winston Kock in the 1940's.

http://120years.net/wordpress/the-baldwin-organ-winston-e-kock-usa-1946/kock/#main (http://120years.net/wordpress/the-baldwin-organ-winston-e-kock-usa-1946/tone_modifying-circuits-baldwinorgan/#main)

[whgeiger]

Not to take anything away from Bart Locanthi, but his design work on acoustic lens' was a product of microwave research conducted by Winston Kock in the 1940's.

http://120years.net/wordpress/the-baldwin-organ-winston-e-kock-usa-1946/kock/#main


The earlier work of Koch & Harvey was referenced in the SMPT Journal article by Locanthi & Frayne (copy attached).

[SEAWOLF97]

http://www.audioheritage.org/vbulletin/showthread.php?35764-Bartholomew-Locanthi-II-in-the-news-obliquely

[Elac310]

Toys


(...)

It dawned on me that if there was Hell on Earth, this was is it for my father. Having built in his home one of the best sound systems on the planet, here he was stuck in a little room with a small TV and the tinny speaker in the all-purpose bedside control box. (...)
I didn't realize until he died why he really wanted to go home. He just wanted to play with his toys.





A great engineer. I keep stumbling on his name when I read RD stuff about JBL, TAD etc. Respect.

I know the feeling myself, when I travel for business and I'm away from my place, after 3 days I start missing a good tune played on my system.

Does anyone know by any chance what Bart's system consisted of ?

[audiomagnate]

I've got a pair of his Pioneer HPM-40's in my office system right now and am enjoying them.

[tomt]

Dorothy N. Davis Locanthi (1913 - 1999)



http://aas.org/files/styles/medium/public/_obit/Deceased_Dorothy_N.%20Davis_Locanthi_1999-09-27_large.png?itok=UjdtQLlt




Dorothy Locanthi died on Monday the 27th of September 1999.


Dorothy Davis Locanthi, a long-time AAS member, died in Glendale, California on September 27, 1999. An only child, she was born Dorothy N. Davis on April 19, 1913 in East St. Louis, IL, where she attended public schools and graduated from high school in three years. After one year at Ferry Hall, a college preparatory school in Lake Forest, IL, she entered Vassar College in 1929. There she majored in physics and took all the astronomy courses she could under Caroline Furness and Maud Makemson. By the time Dorothy graduated in 1933, she had decided there could be no more rewarding career for her than astrophysical research.
She wanted to enter the University of California (UC), where she was accepted, but its funds were limited because of the Great Depression. Her father, a small businessman, was also hit hard by the Depression so Dorothy had to depend on scholarships and her earnings from campus jobs to finance her education. Luckily she received a one-year teaching fellowship at Mills College in Oakland, close to Berkeley and Lick Observatory. At Mills Dorothy wrote an excellent master's thesis on the spectra of S stars, based on spectrograms taken by Paul Merrill at Mount Wilson Observatory. C. Donald Shane of the Berkeley Astronomical Department was her mentor. That Christmas she spent her "vacation" at Mount Hamilton working on her thesis, reading in the library and hoping for a clear night.
In 1934 Dorothy finally received a small assistantship and entered UC. In her third year she was awarded a Lick Observatory Fellowship. Most of the astronomy graduate students divided their time between the two locations. She wrote an outstanding thesis on the spectrum of Antares, based again on high-dispersion spectrograms from Mount Wilson, photographed primarily by Walter S. Adams and Theodore Dunham. Her principal advisers were Shane and the physicist, F.A. Jenkins. Dorothy became an expert on molecular spectra and in identifying many atomic lines of rare elements in this cool supergiant. She completed her PhD in 1937, and then accepted two successive one-year temporary teaching positions at Vassar and Smith. But what she really wanted was to continue research.
Dorothy then received an AAUW postdoctoral fellowship which enabled her to begin work on the spectrum of β Pegasi, an M giant with essentially the same effective temperature as Antares, but a higher density. She did this research at Mount Wilson Observatory, using spectrograms taken there. In 1940 she went to Princeton University as an assistant to Henry Norris Russell. She helped analyze the laboratory spectrum of Eu II. In 1942 Dorothy returned to Mount Wilson as an assistant to Adams and continued her own analysis of β Pegasi. By then America was at war and Mount Wilson was involved in several weapons development programs. She worked on them for a time, and then transferred to Caltech's rocket project. In 1943 she married Bart N. Locanthi, a Caltech student and electronics expert who also worked on this project.
In 1945 Dorothy was at Ray Control Company in Pasadena for a time under Pol Swings, the Belgian astrophysicist who was designing spectrographs for wartime industries. When the war ended she took a well-paying job in the nascent Beckman Laboratory to support her husband until he finished his degree at Caltech. Their first daughter was born in 1948, and Dorothy could not get back to work for two years. In 1950 she started at a half-time job with Franklin E. Roach, the former astronomer who had switched to night-sky research at the Naval Ordnance Test Station, Inyokern, California with an office in Pasadena. But in 1952 the Locanthis' second daughter was born, and Dorothy went back to full-time motherhood until 1962, seven years after their only son, Bart, Jr., was born. Then she was able to get a half-time job at Caltech under Jesse Greenstein, measuring and analyzing his spectrograms of S stars, especially R Andromedae. However, that job ended in 1969 as a result of cuts of government funding of scientific research. But in 1972 Dorothy succeeded in getting another half-time job, this one at JPL. By then her husband was a highly successful engineer, but she lived for science and continued at JPL well into the 1980's, though at reduced hours.
Dorothy loved scientific research, especially measuring and analyzing the spectra of late-type stars, at which she was a master. Mathematically highly gifted, she was an excellent numerical computer, but in the wartime and government projects she was generally assigned to supervise numbers of less adept women, a duty she did not relish. Her published papers on Antares, β Pegasi, S stars, and molecules in cool stars are her great monuments. She enjoyed travel and attending meetings, and presented papers at numerous AAS, ASP, and IAU sessions.
In the early 1990's Dorothy began suffering short-term memory problems. After that she lived with one or the other of her two daughters, Jeanne McLaughlin and Carol Ann Wainwright. Dorothy never had the permanent, full-time research position in astrophysics for which her training, experience, and published papers clearly qualified her, but she certainly made the most of the opportunities she did have.
There are a number of letters to, from, and about Dorothy in the Mary Lea Shane Archives of the Lick Observatory, University of California, Santa Cruz and in the Mount Wilson Observatory Collection, Huntington Library, San Marino.
An obituary article for her was published in Physics Today, 53, April issue, p. 88, 2000.