Many years later, in 1914, his demonstration film Word and Picture was presented to a gathering of scientific dignitaries in Berlin, but his invention was never commercialized.

After a falling out with his father, he left home at the age of 15, supporting himself by working as a handyman and technician in mechanical workshops and shipyards in Helsinki.

He completed his high school education and began studies in electrical engineering at the Friedrichs Polytechnikum [de] in Köthen.

After completing his studies there in 1911, he moved back to Finland with his fiancée Marjatta Nybom, whom he had met and fallen in love with while in Köthen.

Although Tigerstedt was able to complete his work with the sound-on-film technology, the partners' laboratory was eventually confiscated due to unpaid rent.

Tigerstedt continued working on his sound-on-film technology and made progress in solving a major technical problem, that of how to amplify film audio sufficiently to fill a large theatre or hall.

He did this by making major improvements to the vacuum tube design of Lee de Forest, increasing the amplification capacity substantially.

In February–March 1914, Tigerstedt demonstrated his sound-on-film technology to a small group of scientists, using his own film Word and Picture.

In 1923, Tigerstedt moved to the United States where he founded his last company, the Tiger Manufacturing Co., to produce small radio receivers and cryptographic devices.

Exactly one year later, on April 20, 1925, he succumbed to tuberculosis at the New York Fifth Avenue Hospital, possibly due to side effects from his injuries in the car accident.

Film with audio was recognised as a commercially promising field of endeavour, but Tigerstedt's invention needed further development before it could be commercialised.

When his father learned of his thinking, he tried to persuade him to not let his imagination carry him away, " ... otherwise you will surely end your days in the asylum in Lapinlahti."

Tigerstedt stubbornly continued to grapple with the problems of the early vacuum tubes, which were inefficient, expensive and prone to breaking.

Tigerstedt, however, continued to experiment and eventually succeeded in substantially improving on the design of Lee De Forest, achieving much greater amplification than that of the original valves.

Tigerstedt also patented his improvement of the triode vacuum valve, which consisted of improving the amplification by rearranging the electrodes cylindrically in the tube, changing the glass mold to prevent vacuum loss and using steel mirrors inside the tubes to prevent electrostatic interference.

This was a major step forward for Tigerstedt, and he was soon able to show a film with sound which was electronically amplified and reproduced through a speaker system.

Beginning in 1919, de Forest created his own sound-on-film system, which he called Phonofilm and which used some of Tigerstedt's concepts, along with some of the Tri-Ergon group and of inventor Theodore Case.

One month later, Tigerstedt was summoned by the German authorities, told that he had been declared an unwanted Russian citizen, and given three days to leave the country.

Tigerstedt moved to Denmark, where he continued working on film sound recording devices at the Petersen & Poulsen company.