In the old movies, everyone should have seen the phonograph. As the record turns, the golden "big speaker" of the phonograph slowly and leisurely transmits a song "Night Shanghai", a scene you must be familiar with.
But have you ever wondered: the sound cannot be seen or touched, how is it retained by the phonograph?
Typical phonograph image
(Image source: pixabay.com)
What did the original invention of the phonograph look like?
In fact, for a long time, people have not been able to directly preserve the sound, and can only record the sound indirectly through dictation, writing, instruments and other means. It wasn't until Edison invented the gramophone in 1877 that sound was captured for the first time.
Edison and his early phonograph were photographed in 1878
(Image source: References[2])
From the picture, we can see that the phonograph originally invented by Edison did not have the iconic loudspeaker, so the effect of receiving sound was not good. The loudspeaker actually appeared on the second generation of phonographs introduced by Edison in 1888, which improved the effect of receiving and playing sounds by the phonograph, and then there was a box phonograph that hid the horn in a wooden box.
Advertisement for Edison gramophones and box phonographs
(Image source: References[3])
Looking more closely, Edison's phonograph may not be the same as the phonograph in everyone's impression, it does not exist in the shape of a disc record, and the center of the phonograph is a horizontal cylinder. In the phonograph advertisement at that time, there were also large cylinders next to the phonograph, which was called the Phonograph . Today, the Gramophone, which uses disc-shaped records to play sound, was invented by Emil Berliner in 1887.
Bellina's phonograph manuscript (Image: References[4])
and Berinna himself (Image: References[5])
How does a phonograph save and reproduce sound?
In fact, whether it is a record cylinder or a record, the working principle of these phonographs has similarities, and the following uses Bellina's record phonograph as an example.
Bellina's phonograph manuscript
(Image source: References[4])
When receiving sound, the sound is transmitted along the direction of the green arrow from the mouth of the horn to the bottom end of the horn, and the blue connected to the bottom end of the horn represents a disc-shaped diaphragm, which is made of aluminum alloy sheet or mica sheet. The red color attached to the diaphragm indicates the pitching pin, which is made of steel or made of natural diamond set on a copper needle, and the vibration of the diaphragm causes the pitcher to shake in the direction of the yellow arrow. The diaphragm and the tone needle are collectively called the phono head.
The tip of the needle is on the top of the record, and the surface of the record is a special material, made of natural waxes such as beeswax and marmoglin wax after adding chemical agents, and the record will be carved with spiral marks at the same time as the needle tip is rotated, and the sound causes the needle tip to shake, which also makes the carved trace have detail characteristics corresponding to the sound information. Depending on how the stylus is mounted, the engraved marks are divided into horizontal engraving parallel to the direction of record shake and vertical pattern perpendicular to the direction of record shake.
Horizontal and vertical engravings on the record
(Image source: References[1])
When playing the sound, let the tip of the needle maintain a certain pressure on the record, and then turn the record, the tip of the needle will re-scratch these characteristic traces, and the characteristic vibration is transmitted to the diaphragm and horn, thereby restoring the sound recorded on the record.
The difference between a cartridge and a record is that the cartridge leaves a notch on the surface of a rolling cylinder. In the upper right of the figure below is a horn, the surface of the metal cylinder is a flexible metal foil, while turning the threaded metal rod while speaking to the horn, you can drive the pitcher to carve the sound traces on the metal foil. When it is necessary to restore the sound, as long as the engraved metal foil is re-rotated, the pitcher and horn can be driven to make a sound.
Metal foil phonograph produced in 1892
(Image source: References[6])
Why did the record player beat the record player?
Edison initially used tin foil to make a phono, but the effect was not good, and he also limited the practical value of the phonograph to recording speech. Later, the inventor of the telephone, Bell, replaced tin foil with wax, and Edison realized the practical prospect of the phonograph for music, so he and Bell put the phonograph into practical use and continued to develop and improve it. After working for bell telephone for a while, Bell left Bell to develop a record phonograph and started the company.
After continuous improvement of materials and structures, the sound quality of record phonographs and phonographs is getting better and better, and the effects of the two are comparable. However, the record size is small, easy to store, can be quickly generated by turning the mold copy, the volume of the cartridge is very large, but also need to be repeated recording to make copies, so Edison's phonograph was finally discontinued in 1929.
The inventor of the telephone - Bell
(Image source: References[8])
Whether it is the mechanical shaking of the horn and the pitcher, or the hand crank and clockwork to turn the phono and the record, the phonograph initially uses only mechanical power. By the end of the 19th century, various motor generators developed rapidly, large horns were replaced by microphones, and mechanical phono heads were replaced by electric phono heads, so phonographs evolved into electrophono machines.
Although the record player still relies on the turnpiece and notch to record and restore the sound, it no longer relies on simple mechanical conduction, but converts the sound signal into an electrical signal through the microphone, and the electric phono head converts the sound signal contained in the vibration of the electric signal and the needle into each other.
After World War II, with the development of plastics, people made dense records that could carve more fine lines, so that more music could be recorded on one record. When the record player and the dense pattern record are combined, it forms the appearance of the vinyl record player that we are familiar with today.
bibliography:
[1] Edison, Thomas A.. "Edison with Cylinder Phonograph; Washington, DC; April 18, 1878." 1878. Photo courtesy of U. S. Department of Interior, National Park Service, Edison National Historic Site..
[2] LI Enpu,XING Luping. "A Review of the Earliest Recording and Playback Equipment - Phonographs," Sound Technology, 2008(4): 78-81.
[3] "Phonograph Catalog/Advertisement: 'I want a phonograph in every home...'." Edison Manufacturing Co. Inventing Entertainment: The Motion Pictures and Sound Recordings of the Edison Companies, Library of Congress.
[4] Berliner, Emile. Scrap Book. to 1894?, 1885. Image. Retrieved from the Library of Congress, .
[5] Berliner, Emile. Emile Berliner. Young Israel, S.l, 1871. Image. Retrieved from the Library of Congress,.
[6] LI Enpu,XING Luping. "Review of the Earliest Recording and Playback Equipment - Phonograph (2)." Sound Technology, 2008(5):78-81.
[7] https://www.youtube.com/watch?v=UxQyewor27U
[8] https://www.loc.gov/collections/emile-berliner/articles-and-essays/gramophone/
[9] Alexander Graham Bell, half-length portrait. Harris & Ewing, Washington, D.C. Photograph. Retrieved from the Library of Congress, .
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Source: Science Compound
EDIT: Hidden Idiot