Sanyo IMP 500Ω Dynamic Japan Microphone

 

The importance of cameras and film can’t be over stated, but the medium of sound is just as important, as well as a chance to enhance and work with what cameras capture. Whether it is a moving picture using dialogue to tell the story or a showcase of still photos accompanied by music to evoke a certain emotion, the importance of sound in the medium of taking pictures and film can’t be neglected or over looked.

As Brodwell, Thompson and Smith (2017:264-265) writes:

“Sound is a powerful film technique for several reasons. For one thing, it engages a distinct sense mode. Even before recorded sound was introduced in 1926, silent films were accompanied by orchestra, organ, or piano. At a minimum, the music filled in the silence and gave the spectator a more complete experience. More significantly, the engagement of hearing opens the possibility of what the Soviet director Sergei Eisenstein called “synchronization of senses”—making a single rhythm or expressive quality bind together image and sound. The meshing of image and sound appeals to something quite deep in human consciousness. Babies spontaneously connect sounds with what they see. For us, if a sound and image occur at the same moment, they tend to be perceived as one event, not two. Just as our minds search for patterns in a shot or for causal patterns in a narrative, we’re inclined to seek out patterns that will fuse lip movements and speech. The power of musical structure to map onto visual structure is evident not only in dance but also when fans of the Pink Floyd album The Dark Side of the Moon play it back over The Wizard of Oz. Our bias toward audio-visual blending governs both our everyday activities and our experiences of arts like music, theatre, and film.”

Furthermore, sound is also important because it is: “a crucial aspect of our everyday lives. Just think about it – most of us communicate verbally, and it’s pretty hard to understand body language alone. This makes sound the primary source of information. Words help us be clear and hearing a voice can already tell a lot about the message.” (Interactio 2022)

As much as I like talking about cameras and film that I can get my hands on, I would like to also pay my respects to everything and anything sound related that I can get my hands on. Starting with the Sanyo IMP 500ohm Dynamic Japan Microphone.

                     

Or at least that is what I believe this microphone to be. One piece of evidence come from an eBay listing by seha10 (2007). In this listing that microphone is identical to the one I have presented in this post. Everything from the metal plate with the on/off switch, the fact that it is square as well as the typeface and the o and n in on has a significant gap in-between. The writing underneath is also the same, with both saying IMP 500ohm Japan. They both also have the same shape and colour with the only difference being that the listing’s microphone has a shorter cord.

eBay listing 1. Source: https://i.ebayimg.com/images/g/EsAAAOSwLbBlwW2P/s-l960.jpg

eBay listing 2. Source: https://i.ebayimg.com/images/g/EqYAAOSwLbBlwW17/s-l1600.jpg

 

eBay listing 3. Source: https://i.ebayimg.com/images/g/EuYAAOSwB0dlwW19/s-l140.jpg

eBay listing 4. Source: https://i.ebayimg.com/images/g/PCAAAOSw9jtlwW2C/s-l960.jpg

eBay listing 5. Source: https://i.ebayimg.com/images/g/66cAAOSwrwplwW2B/s-l960.jpg
 

Second piece of evidence that this is a Sanyo mic is the exposed resonator cap, that a lot of other Sanyo microphones have. So with this and the listing we can assume that this is a Sanyo IMP 500ohm Dynamic Japan Microphone.

eBay listing 6. Source: https://i.ebayimg.com/images/g/6QwAAOSwJ6BlwW1~/s-l1600.jpg

Sanyo IMP 500ohm vintage mic. Source: https://rvb-img.reverb.com/image/upload/s--9UxYEiy5--/a_0/f_auto,t_large/v1709243195/v0yrf0mjzexbiwzq7loh.jpg

Now for the company’s history. Sanyo was founded in 1949 by Toshio Iue (Sanyo 2023). It was formed after the Matsushita Electric Industrial Co. Ltd. was forced to break up into smaller companies after World War II as a part of the occupations decentralised policy. Most of the Matsushita Electric Industrial Co. Ltd. operations were put in charge to Toshio Iue, who was Konosuke Matsushita’s brother-in-law and partner of the Matsushita Electric company (Reference for Business 2024).

Iue named the company Sanyo, which means Three oceans. This refers to the Indian, Atlantic and Pacific Oceans, because: “the late Toshio Iue, earnest ambition to generate business throughout the world, capitalizing on the company's three core assets: excellent human resources, superior technologies and first-class service.” (Sanyo 2023)

Sanyo manufactured many electrical appliances, like the first plastic radio (1952) and the first “pulsator type washing machine” (1954). By the 1970s Sanyo went international and became in demand in North America when Sanyo started manufacturing home audio equipment. (Annasha 2021).

Now for this microphone. First the name, IMP stands for impedance, which is “the “AC resistance” of audio signal voltages. Impedance controls the flow of the audio signal. In order for a mic signal to travel optimally, the microphone output impedance must “match” or “bridge” the input impedance (load impedance) of its mic preamp.” (Fox 2024).

Or in other words it is “the amount of resistance inherent in the electrical system. It is measured in Ohms, often symbolized with the Greek character for Omega: Ω.” (Presonus 2023). There are also three classes of microphone impedance and the Sanyo IMP 500ohm Microphone falls under the low class (0Ω-600Ω) because well it is 500Ω. (Presonus 2023)

The Sanyo IMP 500ohm Microphone is a dynamic microphone. Dynamic Microphones go back to1897, invented by Ernst Siemens, but the design we know today was released in 1931, which was an improved design by Edward Wente and Albert Thuras (Simmons 2020).

What does it mean that it is a dynamic microphone? Well, the best why is to quote the Shure Incorporated’s (2012:5) Microphone Techniques for Live Sound Reinforcement publication:

“Dynamic microphones employ a diaphragm/voice coil/magnet assembly which forms a miniature sound driven electrical generator. Sound waves strike a thin plastic membrane (diaphragm) which vibrates in response. A small coil of wire (voice coil) is attached to the rear of the diaphragm and vibrates with it. The voice coil itself is surrounded by a magnetic field created by a small permanent magnet. It is the motion of the voice coil in this magnetic field which generates the electrical signal corresponding to the sound picked up by a dynamic microphone. Dynamic microphones have relatively simple construction and are therefore economical and rugged. They can provide excellent sound quality and good specifications in all areas of microphone performance. In particular, they can handle extremely high sound levels: it is almost impossible to overload a dynamic microphone. In addition, dynamic microphones are relatively unaffected by extremes of temperature or humidity. Dynamics are the type most widely used in general sound reinforcement.” 

This microphone is also directional (“A microphone’s sensitivity to sound relative to the direction or angle from which the sound arrives” Shure Incorporated (2012:8)) and each directional microphone has different polar patterns which “determines the sensitivity at different angles…” and “defines how much of the signal will be picked up by the microphone from different directions…” (Tobias 2016).

And the Sanyo IMP 500ohm has a cardioid polar pattern. This pattern “is the most common directional polar pattern, with the highest sensitivity to sound coming in from directly in front of the microphone capsule (0º), practically no sensitivity to sound coming directly from behind (180º), and a reduced sensitivity to sound coming in from the sides (90º/270º)…” and is preferred for studio and music recordings. (Willard 2018).

Cardioid polar pattern 3d. Source: https://sound.stackexchange.com/questions/49957/where-microphone-captures-loudly-in-cardioid-polar-pattern 

Cardioid polar pattern. Source: https://www.soundguys.com/how-to-read-a-polar-pattern-chart-16272/

This microphone doesn’t have a grill, which is used to protect against dust, gusts of wind/breathes and moisture. It seems that a lot of these small type of Sanyo microphones doesn’t have grills. But some do and if this microphone did have one it most likely would’ve had a dome-shaped grill or at least a concave-up dome-shaped grille like the Shure SM57 (Fox 2018).

Shure SM57. Source: https://mynewmicrophone.com/wp-content/uploads/2019/08/mnm_300x300_Shure_SM57.jpg

Traditionally dynamic microphones come with a ball shaped grill (Fox 2018), but because of the shape of the IMP 500ohm, a concave-up grill would be a better fit.

Sanyo model T146 IMP 500. Source: https://www.ebay.ph/itm/285585327692

The Sanyo IMP 500ohm also has a resonator cap (possibly a HF resonator disk). “This is common to dynamic microphones and sit above the diaphragm and The result of these controlled resonances working together is a far better frequency response than the diaphragm alone can provide. Although the quoted frequency response for a typical dynamic microphone extends higher than that of a typical ribbon microphone, once the dynamic microphone reaches its quoted upper limit the high frequency roll-off is usually steeper. Fortunately, dynamic microphone designers are usually able to place the high frequency roll-off somewhere above 12kHz, which is high enough to avoid terms like ‘dull’ and ‘muffled’ – descriptions that would certainly be used if the same steep roll-off occurred just a bit lower…” (Simmons 2020). 

The resonator cap is “used for several decades to refine the high frequency response of microphones. These caps create a resonant cavity in front of the diaphragm to extend and shape the high frequency response.” (Benjamin 2022)

This microphone’s year of manufacture is a bit tricky and the best I can do is when comparing it to other dynamic microphones’ manufacturing years and looking at the evolution of the dynamic, we can assume that the Sanyo IMP 500ohm could be anywhere around the 1970s. More evidence that we can assume that this microphone was released in the 1970s is that it originally came with a cassette tape recorder and that as mentioned above Sanyo released home audio equipment in the 1970s.

This microphone has a double prong aux jack. After testing it, I believe that the bigger one is used to convert the sound wave into electrical signals and the smaller one is to supply the power from whatever it is plugged into. (Or I could be wrong and it is just two different aux jacks to adapt to different recorders.)

Now for a brief explanation on how this microphone works. The best explanation comes from Sweetwater (2023), who writes:

“The way dynamic microphones work is fairly simple. Inside the microphone capsule, a magnet creates a magnetic field that surrounds a small, movable induction coil that’s attached to a diaphragm. When sound waves enter the microphone, they push and pull on the diaphragm, which causes the coil to move, creating a voltage induced by the magnetic field. The resulting voltage is then increased by the use of a transformer and leaves the microphone as mic-level signal.”

What I like about the Sanyo IMP 500ohm is that it is small and lightweight. Even though it is mostly made of plastic, it still looks slick and has a cool vintage look. 

And if there is anything that this post proves is that there goes just as much passion and engineering into sound as with photography and cinematography, making it invaluable element in the entertainment industry.

Thank you for making it to the end and I hope you enjoyed this as much as I did researching it. If you want to help this site out, please consider joining my Patreon: patreon.com/OnlineCurator

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List of sources:

Anasha. 2021. Sanyo Electric – Story of a Japanese Company Which has Become a Subsidiary of Panasonic. https://www.yourtechstory.com/2021/09/01/sanyo-electric-story-of-a-japanese-company-which-has-become-a-subsidiary-of-panasonic/  

Benjamin, G. 2022. Variable Resonator Cap for User-Definable Microphone High Frequency Response. https://www.aes.org/e-lib/browse.cfm?elib=21568

Bordwell, D, Thompson, K, & Smith, J. 2017. Film art: an introduction. 11th ed. New

York: McGraw-Hill.

Fox, A. 2024. Microphone impedance: What is it and Why is it important? https://mynewmicrophone.com/microphone-impedance/

Fox, A. 2018. What are microphone grills and why are they important? https://mynewmicrophone.com/microphone-grilles/

Interactio. 2022. The Importance of Sound Quality. https://www.interactio.io/post/importance-of-sound-quality#:~:text=Sound%20is%20a%20crucial%20aspect,a%20lot%20about%20the%20message.

Presonus. 2023. What is impedance, and how will it affect my recording? https://support.presonus.com/hc/en-us/articles/210046073-What-is-impedance-and-how-will-it-affect-my-recording#:~:text=A%3A%20While%20checking%20out%20the,Greek%20character%20for%20Omega%3A%20%CE%A9.

Reference for Business. 2024. SANYO Electric Co., Ltd. - Company Profile, Information, Business Description, History, Background Information on SANYO Electric Co., Ltd. https://www.referenceforbusiness.com/history2/11/SANYO-Electric-Co-Ltd.html

Sanyo. 2023. About Sanyo. https://www.sanyo-av.com/us/learn/index.php

Seha10. 2007. Vintage Sanyo IMP 500 Dynamic Microphone Made in Japan Black Microphones Tested. https://www.ebay.com/itm/145595981899?chn=ps&norover=1&mkevt=1&mkrid=711-166996-619525-4&mkcid=2&itemid=145595981899&targetid=293946777986&device=c&mktype=pla&googleloc=1028682&poi=&campaignid=20801105710&mkgroupid=156754162540&rlsatarget=pla-293946777986&abcId=&merchantid=115342529&gad_source=1&gclid=CjwKCAjw_LOwBhBFEiwAmSEQAZEZn39Cge1aQKLrNv2hxWXbrxqTNk7ll0VOrFmCimUi8JXNJ10_dRoCigIQAvD_BwE

Shure incorporated. 2012. Microphone Techniques for Live Sound Reinforcement. Illinois: Shure Incorperated.

Simmons, G. 2020. Dynamic Microphones. https://www.audiotechnology.com/tutorials/dynamic-microphones

Sweetwater. 2023. Dynamic Microphones: How do they work? https://www.sweetwater.com/insync/dynamic-microphones-how-do-they-work/

Tobias, T. 2016. Microphone Polar Patterns. https://www.lewitt-audio.com/blog/polar-patterns

Willard, D. 2018. Understanding Microphone Polar Patterns. https://www.azden.com/blog/understanding-microphone-polar-patterns/#:~:text=Cardioid%20(kar%2Ddee%2Doid,sides%20(90%C2%BA%2F270%C2%BA).