Independent Press-Telegram from Long Beach, California on January 4, 1959 · Page 109
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Independent Press-Telegram from Long Beach, California · Page 109

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Location:
Long Beach, California
Issue Date:
Sunday, January 4, 1959
Page:
Page 109
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Silence Cell (Continued from Page 8.) packed with stalactites and stalagmites -- except this cave has them on the sides, too. Without its 15,000 square feet of exposed Fiberglas surface, the original size of thig room- within-a-room w a s 20x18x16 feet Fiberglas is, of course, highly absorbent and a good insulator. It's used in speaker enc l o s u r e s , refrigerators and ovens; in fact, anywhere that noise or heat transmission must be minimized. There is a G-inch space between the chamber and the main t e s t i n g laboratory at Altec. The silent room is supported by neoprene plugs to prevent conducting of outside noise to the chamber itself. A BATTEKY of electronic meters explains the reason for the room. A loudspeaker is placed In the chamber. A microphone is positioned before it, the technician leaves the room and work begins. No tests are conducted with anyone present In the chamber itself. S o u n d waves would bounce 'from the person, creating a s p u r i o u s reading. So meticulous are the researchers that the chamber's dimensions are slightly uneven -- no square corners. The 4- foot length of Fiberglas and · measurements in the chamber, foo, were carefully p l o t t e d mathematically. At the test panel electronically controlled sound emanates from the speaker at ranges well above and below ability of the human ear to hear, and at all stages between. ' A penline device on graph ' paper plots the performance curve of either a speaker or microphone. The combination of test equipment and anechoic chamber "wrings out" whatever is being tested as no mere human could. The silent room is considerably smaller tnan a normal living room but it has a reputation. It's one of the largest in the United States devoted exclusively' to research in .speakers and microphones, although Altec also produces a line of amplifiers and allied equipment, Dr. Fiala, in summing up the a n e c h o i c chamber's purppse, lays, "People have 'ihe'a'dea that building loudspeakers is an art. It is not. It is an exact science in solving problems of physics. In the chamber we can learn how well those problems have '' been solved." The "dead room" is one of six employed by the plant. Three, about the size of small w a 1 k - i n refrigerators, test speakers "on the line," where they must meet a standard set in the laboratory prior to release for shipment. Two smaller ones, about 30 inches in each dimension, are used for microphones. SHIELD OF VALUE BADGE OF BUYING OPPORTUNITY Sean, Roebuck and Co.. this winter a sponsoring a distinguished nwrchojKfisIng program, the SHIELD OF VALUE Watch for it in ow ads, MI selected lest Selling merchandise. Pitt--regular fused style stays crisp Lynn--soft, medium spread, with stay* Port--short points, medium spread, fused · Selected best-sellers will receive the SHIELD · Shield items will be sold at drastic reductions · Reductions in price will range up to one-third · The SHIELD adds to your purchasing power en's Pilgrim 2.98 Dress Shirts ... with extra features of other nationally branded broadcloth shirts selling for $4! · ! Hurry! priced Low because Sears bought during the maker's slow season Check these extra features · Clock says midnight, but your Formease collar it still I a.m. fresh. Fits both neck a«d shoulder curves . . . that's why It never curls or wilts. · Thrifty way to add wardrobe versatility: get shirts with th* 3 varied collars at left and switch 'em as you change outfits --- a flattering effect! All fresh, first-quality stock ... no seconds! · ProportioKd from collar to tails . . . ajra »o« COM. fortabl* freedom from bunching as wall at tt» clegoK* that gen with a not fit. · Na odd* and ends! Full siie ranges of eottM broadcloth, with choice of white, solid washfast colon or stripes !· each she . . . all Saiforiied! I 3.98 Masterfully tailored Pilgrim deluxe dress shirts 3 for $9 I -Downtown Long Beach

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