1915: The first public presentation of the electrodynamic speaker

worlds first electromagnetic speaker, #100yos

worlds first electromagnetic speaker, #100yos

Even before earning his reputation as inventor of the loudspeaker in 1915, Peter L. Jensen carved his name into fame. Working as an assistant at the then famous Valdemar Poulsen company, reputed for its arc generators for wireless transmission in communications systems, Jensen found the solution to wireless transmission of voice and not only Morse signals, which had otherwise to that time been the way of wireless transmission. Aims to achieve this vital goal had been high on the agenda of the Pouslen company. However, the company’s chief engineer Schou with assistance of Jensen had failed to make it work in experiments in 1906. An evening a few days later, Jensen and two of his roommates from Copenhagen went to the Poulsen lab in Lyngby . That night, almost by accident, Jensen stumbled across the solution of making voice transmission work in wireless. The three, Jensen and his two roommates from Copenhagen, none of the latter two actually being involved in the company, were the first people in world to practice and experience wireless transmission of speech. After the breakthrough, during the following two years, Jensen would frequently at night transmit music wireless from an arc transmitter at the Poulsen lab in Lyngby. Since at the time radio receivers were restricted by law to military and ship communication purposes, private use was prohibited. Hence the audience to receive the world’s first radio transmission was rather limited at the time. Jensen would use an old Edison phonograph connected to a Poulsen arc transmitter to transmit the music.

March 4, 1909, a 16 year young student, Einar Dessau, who had managed to build his own amateur receiver from instruction given by Jensen, seems to have been the first private audience in the world, listening to “Carneval in Venice” by Johan Straus, that night being transmitted by Jensen from his old wax drum phonograph. However, Dessau would later on give up his ‘dreams’ of becoming an electronic engineer, instead focused on mechanical engineering and after a few years in the USA became managing director of Danish brewer company Tuborg.

Commissioned by Pouslen, Peter Jensen transferred to California to help set up the first Poulsen generators in the USA for the ‘Poulsen WirelesTelephone & Telegraph s Company’, PWTTC. That company had acquired all licensing rights for the USA for the Pouslen arc generator. Peer Jensen had left Denmark on December 9,1909 together with an American mechanical engineer, Carl Albertus, who had to Denmark from Chicago to be trained in the equipment. The first arc transmitter installation was done in Sacramento, and later on in other cities of California. During this task, Jensen met the 5 years older Stanford educated engineer, Edwin Pridham, and lifelong friendship was started. The two of them would later on become the ‘fathers ogf the loudspeaker’

When the Poulsen WirelesTelephone & Telegraph Company in the USA was split up in late 1910 into a telegraph company and a wireless telephone company, Jensen had considered his job done and planned to go back to Denmark. However, Jensen and Pridham were approached by a group of investors wanting to set up a new wireless company, since wireless had become a high growth business at the time. The investors wanted Jensen, with assistance of Pridham, to go back to Denmark and set up an agreement with his former principal, Valdemar Poulsen, to obtain the licensing rights for Poulsen arc generators for Canada and Ireland, since the USA had already been obtained by the Poulsen Wireless in the USA.

The attempt failed, since Jensen and Pridham found out during their trip to Copenhagen that a British syndicate under the dominant Lord Armstrong consortium, major supplier of munition to the British military, had already acquired the right. Returning to the USA and although lacking results of the jorney, some of the investors lead by O’Connor, a soap and candle manufacturer from San Francisco, still wanted to go along with Jensen and Pridham. The y formed the company Commercial Wireless and Development Company and set up a research lab for them in remote Napa, in Napa valley north of San Francisco. At this little village they established their R&D lab in small bungalow on February 22. 1911. The two made various experiments with other Valdemar Poulsen items, including a “tikker”, a galvanometer based unit that Poulsen had invented to recording up to several hundred characters per minute during Morse transmissions.

On December 10, 1915, Jensen and Pridham presented their groundbreaking invention – the first electrodynamic loudspeaker – to the public for the first thime in Golden Gate Park, San Francisco. The next day The San Francisco Bulletin published an enthusiastic article about the event: “Great invention made of Californians solves many problems. The slender tone of a single violin heard about a mile away. The sound operatic Luisa Tetrazzini’s voice reverberating throughout the sdtadium, and a piano solo resembling the chimes of Westminster Abbey played  by Colossus of Rhodes”.

The loudspeaker was born.



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