Histricamente, para obtener una RI de un recinto, se utilizaba como seal de excitacin rfagas de ruido filtrados por bandas o disparos de pistola. La desventaja de este mtodo es la pobre relacin seal-ruido debido a que su energa est concentrada en un pequeo intervalo de tiempo. Esto impone, la utilizacin de impulsos de niveles elevados que para el primer caso requeran altoparlantes especiales que sean capaces de manejar sin distorsin dichas seales y sin riesgo de ruptura. En la actualidad, es habitual utilizar seales continuas que mediante procesamiento a posterior permitan obtener la RI con un incremento en la SNR. Estas tcnicas, conocidas como mtodos indirectos, han sido adoptadas por la normativa especfica al estudio de salas ISO ,
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His father Edward Fred Beranek was a farmer whose ancestors came from Bohemia in what is now the Czech Republic and his mother Beatrice Stahle, previously a schoolteacher, had become a farmwife. After his first year, he rode in a horse-drawn school bus on a two-hour trip to a somewhat larger school.
In his family moved back to Solon, where he was soon skipped over third grade and moved directly into fourth grade classes. His eldest son became fascinated with both the technology and the musical aspects of radio. In junior high school Beranek earned his first independent money by selling silk stockings and fabric. The younger Beranek quickly learned the trade, and was soon able to buy a Model T automobile. He also earned some spare cash by playing trap drums in a 6-person dance band.
He continued to excel in his studies, including a typing class rarely studied by boys where he was the top performer. In the summers of and Beranek worked as a field hand on local farms, to earn tuition money and to improve his physical condition.
Beranek moved into two rooms above a bakery, shared with three other students to save money. He also continued to repair radios and played in a dance band, but falling income forced him to consider dropping down to a single class in mathematics during the next academic year. This was his first trip to a big city and it was a revelation. He attended concert performances by the Chicago Symphony and Detroit Symphony daily, was dazzled by the displays of industrial products and technology, and fascinated by the international pavilions.
In fall of , he bought an early disc sound recorder to earn a modest fee by recording students before and after taking a speech training class. This was his first hands-on experience with the developing science of acoustics.
By early he was forced to drop out of college and work full-time to earn more tuition money. While there, he also met and dated Florence "Floss" Martin, a business school student. He was able to save enough money to attend the Spring semester at Cornell College, then returned to Collins Radio for the summer.
In August Beranek had a chance encounter with a stranger whose car had developed a flat tire while passing through Mount Vernon. While helping the stranger who turned out to be Glenn Browning , he learned that the passing motorist had written a technical paper on radio technology. When Beranek mentioned plans for graduate school, Browning encouraged him to apply to Harvard University , a possibility he had regarded as financially out of reach.
Beranek graduated from Cornell College in summer with a Bachelor of Arts. He continued studies at Harvard University , where he received a doctorate in In Beranek became involved with a small company called Hush-A-Phone , which marketed a cup that fit over the mouthpiece of a telephone receiver in order to prevent the person speaking from being overheard.
Although Hush-A-Phone had been around since the s, Beranek used his acoustical expertise to develop an improved version of the device. The resulting legal case, Hush-A-Phone v. United States , resulted in a victory for Hush-A-Phone. In , at the age of 98, he collaborated with Tim Mellow to produce an updated and extended revision, published under the new title Acoustics: Sound Fields and Transducers. Beranek has participated in the design of numerous concert halls and opera houses , and has traveled worldwide to conduct his research and to enjoy musical performances.
From to , Beranek was chairman of the board of the Boston Symphony Orchestra , where he remained a Life Trustee. He also served on the MIT Council for the Arts , "an international volunteer group of alumni and friends established to support the arts at the Massachusetts Institute of Technology".
He turned in September , an occasion marked by a special celebration at Boston Symphony Hall.
Acustica - Leo Beranek
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