Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
HARRY F. OLSON December 2S, ~ 901-Aprit 1!, it 982 BY CYRIL M. HARRIS HARRY F. OLSON, pioneer in acoustics and electronic sound recording, died on April I, 1982, at Princeton Meclical Center at the age of eighty-one. He had been a mem- ber of the National Academy of Sciences since 1959. During his career of nearly forty years with RCA, Dr. Olson developed several types of microphones for broad- casting and recording, high-fidelity loudspeakers, phono- graph pickups and recording equipment, underwater sound equipment, and sound motion picture ant! public adctress systems; he contributed substantially to the development of the RCA magnetic tape recorder for television and the RCA music synthesizer. Harry F. Olson was born in Mt. Pleasant, Iowa, on Decem- ber IS, 1901, the first of two children. Both his father, a farmer, and mother, a talented amateur artist, were born in Sweden and had come to this country to seek new opportu- nity. Their son exhibited an interest in science and technology at an early age, which they encouraged by supplying him with a modest shop and laboratory. While still in grade school and with very little data on (resign, Harry built and flew mocle! airplanes an art then in its infancy. In high school he grad- uated to building a steam engine and a woocI-firecl boiler, 407
408 BIOGRAPHICAL MEMOIRS which he user! to drive a direct current generator constructed from parts of an automobile generator he had rewound for ~10 volts. He also designecT and built an amateur radio sta- tion, became proficient with the code, and obtained an op- erator's license. In 1924, majoring in electrical engineering, Harry grad- uatec! near the top of his class from the University of Towa's College of Engineering. G. W. Stewart, then head of the physics clepartment, chose him to receive a graduate schol- arship, and in 1925, he earned the M.A. degree with a thesis on acoustic wave filters in solicis. As part-time research as- sistant to I. A. Eldridge, he worked on polarization of light by electron impact; while with A. Ellett he conclucted re- search on atom beams. One experiment, verifying the Maxwell velocity distribu- tion of atoms, used a small boiler partially filled with cad- mium and equipped with a narrow aperture to supply a fine beam of atoms. The atom beam was sent through a series of Fizeau wheels driven by the squirrel-cage rotor of an induc- tion motor, all operating in a vacuum. The three-phase stator windings of the induction motor were located outside the vacuum chamber. The atom beam passed through the slots in the wheels anct the atoms were collected on a glass plate cooled by liquict air. They then measured the density of the collected atoms. From the dimensions, geometry, rotational velocity, and clensity, the researchers determined the velocity distribution. They then reflected a narrow beam of cadmium atoms from a rock salt crystal and found that the reflection was specular. For his doctoral thesis, Olson carried out re- search on the polarization of resonance radiation in mercury and received the Ph.D. degree in 1928. From his association with Stewart, the inventor of the acoustic wave filter, and with Dean Car} E. Seashore, who specialize<] in the psychology of music, Harry C)Ison clevel-
HARRY F. OLSON 409 oped an interest in music, acoustics, and sound reproduction. In 192S, he joiner! RCA as a member of the Research De- partment. Except for the two-year perioc! from 1930 to 1932, when he was associates! with the Engineering Department of the Photophone Division of RCA in New York City, Dr. Olson was associated with the RCA research organization continu- ously until his retirement. In 1934 he was placed in charge of acoustical research for the RCA Manufacturing Company. In 1942 his Acoustical Research Laboratory was moved from Camden, New Jersey, to the newly constructed RCA Labo- ratories in Princeton, New Jersey, where he had a well- equippe`1 acoustical facility, constructed under his supervi- sion. This included a free-fielc! (anechoic) room that was the worId's largest at that time, a reverberation chamber, ant! an ideal listening room. He continued as director of acoustical research until 1967, when he was appointed staff vice-presi- clent. Dr. Olson's work on the development of microphones for the motion picture anc! broadcast industries resulted in mi- crophones that founct widespread] commercial use. Especially noteworthy were his bidirectional velocity microphones and his unictirectional cardioid microphones. He continued to develop new types of microphones, inclucling higher-orcler gradient microphones, ultra-clirectional microphones, noise- cancelling microphones, and various types of miniature mi- crophones which were usect both in industry anti in the mil- itary. He also developed loudspeakers that made significant improvements in linearity anct uniformity in frequency re- sponse of loucispeakers that were commercially available at the time. During WorIct War IT, Dr. Olson and the group he led workoct on various military projects with an emphasis on un- derwater sound! and antisubmarine warfare. This work in- cluded significant improvements in sonar transducers; the
410 BIOGRAPHICAL MEMOIRS development of an acoustic proximity fuse for depth charges, . · · · . ~ · · ~ and voice communication transducers tor use In noisy env~- ronments. During the academic years from 1940 to 1942, he also lectured in acoustical engineering at Columbia Univer- sity. Following World War IT, Dr. Olson continuer! his research in sound reproduction. One of his experiments, now consid- ered a classic, determined the preferrer! bandwidth for the reproduction of music. Previous experimenters had found that listeners seemed to prefer a high-frequency cutoff of 5000 Hz for reprocluced music. Dr. Olson carried out an experiment in which a small orchestra sat behind a visually opaque but acoustically transparent screen. The screen in- corporatec3 a concealed low-pass acoustical filter having an upper frequency cutoff of 5000 Hz. This filter could be opened or closed, allowing either the full range of frequen- cies to pass or the range only below 5000 Hz. The listeners were asked to select their preference between two conditions: full bandwidth or restricted bandwicith. There was over- whelming preference in favor of the full bandwidth. Next, the orchestra was replaced with a sound-reproduction system where the loudspeakers were located in the position of the orchestra, behind the screen. When the sound system was free of distortion, the listeners preferrer! the full bandwidth. But when he introducect small amounts of nonlinear clistor- tion, the restricted bandwidth was preferred, thus demon- stratin~ clearIv the importance of high Quality in audio sYs- ~--~ --------rig --em- ~~-~ tems. Early in 1950, RCA asked Dr. Olson to develop a team in his laboratory to make significant improvements in magnetic tape recording that could lead to the magnetic tape recording of television signals. To accomplish this wouIc! require a breakthrough in the quality of both the magnetic tape ant! the recording heacis. The 3M Company was selected as the
HARRY F. OLSON 411 collaborator for providing the special tape needed for this new process. In May 1956, after several years of develop- ment, the system was completed and was moved from his laboratory in Princeton to the NBC Studios in New York City, where it provided the worId's first broadcast of tape-recorded color television signals. Dr. Olson then started a project in tape-coating technology in his laboratory. When finally de- veloped, this equipment was transferred, as a unit, to RC\s newly created Magnetic Products Division in Indianapolis, where it was used in the commercial production of magnetic tapes. Dr. Olson's interest in musical acoustics led to the devel- opment, with Herbert Belar, of the RCA Electronic Music Synthesizer. Music synthesizers have become commonplace since the advent of transistors and integrated circuits. But in the era of vacuum tubes and relays, of which the RCA device was constructed, the production of an arbitrarily selected au- dio signal by means of a synthesizer was a considerable achievement. At first, Olson and Belar's synthesizer was used at the RCA Laboratories at Princeton to compose musical selections that were issued as records. It was later moved to the Electronic Music Center at Columbia University, where it is still in use. For his achievements, Dr. Olson received many honors and awards, including the Modern Pioneer Award of the Na- tional Association of Manufacturers ~ ~ 940), the John H. Potts Medal of the Audio Engineering Society (1952), the Samuel L. Warner Medal of the Society of Motion Picture and Tele- vision Engineers (1955), the John Scott Medal of the City of Philadelphia (1956), the Achievement Award of the IRE Pro- fessional Group on Audio (1956), the John Ericsson Medal of the American Society of Swedish Engineers (1963), the Emile Berliner Award of the Audio Engineering Society (1965), and the Institute of Electrical and Electronic Engi-
412 BIOGRAPHICAL MEMOIRS neers' Mervin }. Kelly Medal (1967), Consumer Electronics Award (1969), and Lamme Medal (1970~. He was awarclect the first Silver Medal in engineering acoustics of the Acoustical Society of America in 1974 and in 1981 was given the GoIct Medal of the Society with the fol- lowing citation: ". . . for his innovative anct lasting contribu- tions in acoustic transduction, sound reproduction, elec- tronic music and speech synthesis, and his service to the Society." He server! on the Executive Council of the Society from 1937 to 1940, as vice-president from 1942 to 1944, presiclent-elect from 1951 to 1952, anct president from 1953 to 1954. He was, in aciclition, associate editor of the Journal of the Acoustical Society of America for thirty years. He was a member of the American Society of Motion Pic- ture anct Television Engineers, Fellow of the American Phys- ical Society, Fellow of the Institute of Electrical ant! Electronic Engineers, anct Fellow of the Acoustical Society of America. Dr. Olson was an honorary member, a founder, anct past- president of the Audio Engineering Society. He was also a member of Tau Beta Pi and Sigma Xi and received an hon- orary D.Sc. degree from Iowa Wesleyan College. Dr. Olson was the author of numerous acoustical studies ant! contributed to more than 130 articles and professional papers. His books, Elements of Acoustical Engineering (1940, ~ 947), Dynamical Analogies ~ ~ 942, ~ 958), Musical Engineering (1952), Acoustical Engineering (1957), and Music, Physics and Engineering ~ ~ 966), are widely used by students and engineers throughout the world. Acoustical Engineering ant! Dynamical Analogies, particularly, are considered! standard! reference texts in the field anct have been translated into Russian and Japanese. Dr. Olson hell! more than one hundred] U.S. pat- ents awarder! on devices and systems in the field of acoustics, a partial list of which follows. The titles given here are de- scriptive and are not the actual titles recorcled on the patents.
HARRY F. OLSON 413 Many of his patents are considered to be fundamental as, for example, patents on the velocity microphone, the car- dioict microphone, functional sound absorbers, the electronic music synthesizer, the air-suspension loudspeaker, and the electronic sounc! absorber. Harry Olson retirect in ~ 967 but continued as a consultant to RCA Laboratories for several years thereafter. He is sur- vivec! by his wife, the former Lorene Johnson of Morris, Il- linois, whom he marriec! in 1935. In their early years, Lorene helped him to prepare the manuscripts for his many books and articles. Like his mother, she was an amateur artist, and her prominently clisplayed oil paintings enlivened his office walls throughout his career.
414 BIOGRAPHICAL MEMOIRS HONORS AND DISTINCTIONS DEGREES AND HONORARY DEGREES 1924 B.E., University of Iowa 1925 M.S., University of Iowa 1928 Ph.D., University of Iowa 1932 E.E. (Professional), University of Iowa 1959 D.Sc. (Honorary), Iowa Wesleyan MEMBERSHIPS Tau Beta Pi Sigma Xi Acoustical Society of America, Past-President Audio Engineering Society, Past-President Society of Motion Picture and Television Engineers Institute of Electrical and Electronic Engineers American Society of Swedish Engineers American Physical Society National Academy of Sciences HONORS AND AWARDS 1940 Modern Pioneer Award of the National Association of Man- ufacturers 1952 John Potts Gold Medal of the Audio Engineering Society 1955 Samuel L. Warner Gold Medal of the Society of Motion Pic- ture and Television Engineers 1956 The John Scott Medal of the City of Philadelphia 1956 The Achievement Award of the Institute of Radio Engi- neers 1963 John Ericsson Gold Medal of the American Society of Swed- E. . IS. ~ IlglIleerS 1965 The Emile Berliner Award 1967 Mervin I. Kelly Medal of the Institute of Electrical and Elec- tronic Engineers 1969 Consumer Electronics Award of the Institute of Electrical and Electronic Engineers 1970 Lamme Gold Medal of the Institute of Electrical and Elec- tronics Engineers 1974 The First Silver Medal of the Acoustical Society of America
HARRY F. OLSON PATENTS 1932 Velocity Microphone 1932 Unidirectional Cardioid Microphone 1935 Double Voice Coil Loudspeaker 1940 Multiple Flare Horn 1941 Line Microphone"Shotgun Microphone" 1942 Multiple Loudspeakers 1949 1950 1950 1951 1953 1958 1961 1961 1961 1963 1964 Air Suspension Loudspeaker Synthetic Reverberation Functional Sound Absorbers Single Element Cardioid Microphone Noise Discriminator, Threshold Type Electronic Music Synthesizer Speech Analyzer Electronic Sound Absorber Music Composing Machine Stereophonic Loudspeaker Stereophonic Disk System 415 1,885,001 1,892,645 2,007,748 2,203,875 2,228,886 2,269,284 2,490,466 2,493,638 2,502,016 2,539,671 2,645,684 2,855,816 2,971,058 2,983,790 3,007,362 3,104,729 3,118,977
416 BIOGRAPHICAL MEMOIRS SELECTED BIBLIOGRAPHY 1926 With I. A. Eldridge. Polarization by electron impact. Phys. Rev. 28~6~: 1151. 1928 With A. Ellett. Reflections of atoms by crystals. Phys. Rev., 31~4~:643. Polarization of resonance radiation in mercury. Phys. Rev., 32(3):443. 1929 With A. Ellett and H. A. Zahl. The reflection of atoms from crys- tals. Phys. Rev., 34~31:493. 1930 With Irving Wolff. Sound concentrator for microphones. J. Acoust. Soc. Am., 1 (3) :410. 1931 The ribbon microphone. l. Soc. Motion Pict. Eng., 16~6~:695. A new high efficiency theater loudspeaker of the directional bade type. i. Acoust. Soc. Am., 2~4~:485. Mass controlled electrodynamic microphones; the ribbon micro- phone. I. Acoust. Soc. Am., 3~1~:28. 1932 Recent developments in theater loudspeakers of the directional baffle type. J. Soc. Motion Pict. Eng., 18~5) :571. The velocity microphone. RCA Broadcast News., 5:6. 1933 With Frank Massa. A high quality ribbon receiver. Proc. Inst. Radio Eng., 21~5~:673. With Julius Weinberger and Frank Massa. Unidirectional ribbon microphone. l. Acoust. Soc. Am., 6~21: 139. On the collection of sound in reverberant rooms with special ref- erence to the application of the ribbon microphone Proc. Inst. Radio Eng., 21 (5) :655.
HARRY F. OLSON 1934 417 With Frank Massa. Applied Acoustics. Philadelphia: P. Blakiston's Son & Co. A new cone loudspeaker for high fidelity sound reproduction. Proc. Inst. Radio Eng., 22~11:33. With Frank Massa. On the realistic reproduction of sound with particular reference to sound motion pictures. I. Soc. Motion Pict. Eng., 23~2) :22. With Richard Carlisle. A lapel microphone of the velocity type. Proc. Inst. Radio Eng., 22~12~:1354. 1936 Sound reinforcing systems. RCA Rev., 1~11:49. With Frank Massa. A compound horn loudspeaker. J. Acoust. Soc. Am., 8~1~:48 A new monitoring telephone receiver. T. Soc. Motion Pict. Eng., 27~51:537. With R. A. Hackley. Combination horn and direct radiator loud- speaker. Proc. Inst. Radio Eng., 24~121:1557. A unidirectional microphone. l. Soc. Motion Pict. Eng., 27~3~:284. 1937 Horn loudspeakers, part 1. RCA Rev., 1 (21:68. Horn loudspeakers, part 2. RCA Rev., 2~41:265. 1938 Ultra directional microphone. RCA Broadcast News, 28:32. A horn consisting of manifold exponential sections. I. Soc. Motion Pict. Eng., 30~5) :511. 1939 The unidirectional microphone. RCA Broadcast News, 30:3. Line microphones. Proc. Inst. Radio Eng., 27~7~:438. Multiple coil, multiple cone loudspeakers. J. Acoust. Soc. Am., 10~1):305. 1940 Elements of Acoustical Engineering. New York: D. Van Nostrand Com- pany.
418 BIOGRAPHICAL MEMOIRS 1941 Tone guard. I. Acoust. Soc. Am., 12~3~:374. Line microphones. [. Soc. Motion Pict. Eng., 36~31:302. Extending the range of acoustic reproducers. Proc. Radio Club Am., 18~1~:1. 1943 Dynamical Analogies. New York: D. Van Nostrand Company. 1944 The action of direct radiator loudspeakers. I. Acoust. Soc. Am 16~1): 1. Polydirectional microphone. Proc. Inst. Radio Eng., 32~21:77. 1946 With John Preston. Wide range loudspeaker developments. RCA Rev., 7~21:155. Functional sound absorbers. RCA Rev., 7~41:508. Gradient microphones. I. Acoust. Soc. Am., 17~31:192. 1947 Elements of Acoustical Engineering, 2d ed. New York: D. Van Nos- trand Company. Mechano-electronic transducers. }. Acoust. Soc. Am., 19~2~:307. With R. A. Hackley, A. R. Morgan, and l. Preston. Underwater sound transducers. RCA Rev., 8~4~:698. Audio noise reduction circuits. Electronics, 118. 1949 Single element unidirectional microphone. J. Soc. Motion Pict. Eng., 52~3) :293. With John Preston. Directional microphone. RCA Rev., 10~3~:339. With John Preston and D. H. Cunningham. New 15 inch duo-cone loudspeaker. Audio Eng., 33~10~:20. With John Preston and D. H. Cunningham. Duo-cone loud- speaker. RCA Rev., 10~4) :490.
HARRY F. OLSON 1950 419 With Adolph R. Morgan. A high quality sound system for the home. Radio TV News, 15~5) :59. With J. C. Bleazey, J. Preston, and R. A. Hackley. High efficiency loudspeakers for personal radio receivers. RCA Rev., 11 ~ 1):80. Sensitivity, directivity, and linearity of direct radiator loudspeakers. Audio Eng., 34~101:5. With John Preston. Unobtrusive pressure microphone. Audio Eng., 34~7~:18. 1951 Direct radiator loudspeaker enclosures. Audio Eng., 35~11~:34. Cabinets for high quality direct radiator loudspeakers. Radio TV News, 16~5~:2. 1952 With }. Preston and I. C. Bleazey. Uniaxial microphone. IRE Trans. Audio, AU1~4~:12. Musical Engineering. New York: McGraw-Hill. 1953 With I. Preston and I. C. Bleazey. The uniaxial microphone. RCA Rev., 14~11:47. Matched line of hifi equipment. Audio Eng., 37~8~:29. With Everett G. May. Electronic sound absorber. I. Acoust. Soc. Am.,25~6~:1130. 1954 With John Preston. A new line of hifi loudspeakers. Radio TV News, 51~2~:69. With John Preston and Everett G. May. Recent developments in direct-radiator high-fidelity loudspeakers. I. Audio Eng. Soc., 11~4~:219. A review of twenty-five years of sound reproduction. I. Acoust. Soc. Am., 26~51:637. 1955 With Herbert Belar. Electronic music synthesizer. }. Acoust. Soc. Am., 27~3~:595.
420 BIOGRAPHICAL MEMOIRS 1956 Electronic control of noise, vibration, and reverberation. I. Acoust. Soc. Am., 28~5~: 116. With W. D. Houghton, A. R. Morgan, M. Artzt, l. A. Zenel, and J. G. Woodward. A magnetic tape system for recording and re- producing standard FCC color television signals. RCA Rev., 15~3~:330. With J. Preston and I. C. Bleazey. Bigradient unidirectional micro- phone. RCA Rev., 17~4) :522. With Herbert Belar. Phonetic typewriter. J. Acoust. Soc. Am., 28~6~: 1072. 1957 Acoustical Engineering. Princeton: D. Van Nostrand Company. With H. Belar. Phonetic typewriter. IRE Trans. Audio, AU5~4~:91. 1958 Dynamical Analogies, 2d ed. Princeton: D. Van Nostrand Company. Stereophonic sound reproduction in the home. I. Audio Eng. Soc., 6~2~:80. With John Preston. The electrostatic uniangular microphone. J. Soc. Motion Pict. Eng., 67~11~:751. 1959 A review of stereophonic sound reproduction. RCA Eng.,5~2~: 13. Stereophonic sound reproduction. In: Proceedings of the Third Inter- national Congress on Acoustics. Amsterdam: Elsevier Publishing Company. Acoustoelectronic auditorium. T. Acoust. Soc. Am., 31~7~:872. 1960 With Herbert Belar. Acoustics of sound reproduction in the home. J. Audio Eng. Soc., 8~1~:7. With John C. Bleazey. Synthetic reverberation. I. Audio Eng. Soc., 8~1~:37. High fidelity sound reproduction. Inst. Radio Eng. Stud. Q., p. 10. With Herbert Belar. Time compensation for speed of talking in speech recognition machines. IRE Trans. Audio, AU8~3~:87.
HARRY F. OLSON 421 With H. Belar and I. Timmens. Electronic music synthesis. }. Acoust. Soc. Am., 32~3~:311. 1961 With I. Preston and i. C. Bleazey. Personal microphones. i. Audio Eng. Soc., 9(4) :278. With Herbert Belar. Phonetic typewriter III. I. Acoust. Soc. Am. 33(1~: 1610. With Herbert Belar. Aid to music composition employing a ran- dom probability system. I. Acoust. Soc. Am., 33~9~: 1163. 1962 Loudspeakers. Proc. Inst. Radio Eng., 50~5~:730. Analysis of the effects of nonlinear elements upon the perform- ance of a back enclosed, direct radiator loudspeaker. I. Audio Eng. Soc., 1 0~21: 1 56. With Herbert Belar. Recognition of the spoken word by machine. In: Biological Prototypes and Synthetic Systems, vol. 1. New York: Plenum Press. With Herbert Belar. Syllable analyzer, coder, and synthesizer for the transmission of speech. IRE Trans. Audio, AU10(11: 11. With Herbert Belar. Printout system for the automatic recording of the spectral analysis of spoken syllables. J. Acoust. Soc. Am., 34(2): 166. Speech machine considerations. Fourth Int. Cong. Acoust. (Co- penhagen), Paper G4. With Herbert Belar and Ricardo deSobrino. Demonstration of speech processing system consisting of a speech analyzer, trans- lator, typer, and synthesizer. J. Acoust. Soc. Am., 34(10):1535. 1964 Speech processing systems. IEEE Spectrum, 1 (2) :90. The RCA Victor dynagroove system. J. Audio Eng. Soc., 12(2):98. Unitized stereophonic loudspeaker with acoustically augmented separation of the sound sources. J. Audio Eng. Soc., 12(1~:40. 1965 Advances in sound reproduction. Rapp. 5th Congr. Int. Acoust. (Liege), vol. 2.
422 BIOGRAPHICAL MEMOIRS Passive and active acoustics in architectural enclosures. I. Acoust. Soc. Am., 12~4~:307. 1966 Solutions of Engineering Problems by Dynamical Analogies. Princeton: D. Van Nostrand Company. Research in sound reproduction. RCA Eng., 12~2~:40. With Herbert Belar and Edward S. Rogers. Research towards a high efficiency voice communication system. I. Audio Eng. Soc., 14~3~:233. Sound reproduction in the home. RCA Eng., 12~2~:46. 1967 Music, Physics, and Engineering. New York: Dover Publications. Directional microphones. I. Audio Eng. Soc., 14~4~:420. With Herbert Belar and Edward S. Rogers. Speech processing techniques and applications. IEEE Trans. Audio Electroacoust., AU-153: 120. High quality monitor loudspeakers. dB, 1 ~ 121: 12. 1968 With John E. Volkmann and Adolph R. Morgan.360° conical wave- front loudspeaker for New York World's Fair. I. Audio Eng. Soc., 16~2~: 130. 1969 Home entertainment: Audio 1988. J. Audio Eng. Soc., 17~4~:654. Direct radiator loudspeaker enclosures. I. Audio Eng. Soc., 17~1~:22. Calibration of microphones by the principles of similarity and rec- iprocity. I. Audio Eng. Soc., 17~6~:654. 1970 Ribbon velocity microphones. }. Audio Eng. Soc., 18~3~:263. 1971 Electronic music synthesis for recordings. IEEE Spectrum, 8~3~: 18.
H A RRY F. O LS O N 423 1972 Modern Sound Reproduction. New York: Van Nostrand Reinhold Company. Microphone thermal agitation noise. I. Acoust. Soc. Am., 51 (2~:425. The measurement of loudness. Audio, 56~2~: 18. Psychology of sound reproduction. Audio, 56~6~:20. Field type artificial voice. J. Audio Eng. Soc., 20~61:446. 1973 Gradient loudspeakers. I. Audio Eng. Soc., 21~2~:86. How Caruso shattered wine glasses. I. Audio Eng. Soc.,21~10~:836. 1974 Field type acoustic wattmeter. I. Audio Eng. Soc., 22~5~:321. 1975 A history of high quality studio microphones. I. Audio Eng. Soc., 24~11/12~:798. 1977 Microphones for recording. J. Audio Eng. Soc., 25~10/11~:676.