RPKIT50
RP Stereo Headphone Assembly Kit
RPKIT50
Assembly kit for headphones with a planar driving diaphragm employing RP (Regular Phase) technology
RPKIT50 is a kit product that allows you to assemble stereo headphones equipped with our originally developed driver unit "RP diaphragm" that employs RP (Regular Phase) technology. By attaching and adjusting multiple sound quality adjustment parts with reference to the tuning change table, users can enjoy creating sound quality to suit their preferences and applications, such as for music appreciation and monitor headphone specifications for music production.
Limited quantity offer
Decals and stickers for decorating the headphones are presented!
They will be included in the package. The offer will end as soon as we run out of the planned number of decals.
Decals and stickers for decorating the headphones are presented!
They will be included in the package. The offer will end as soon as we run out of the planned number of decals.
Features
Fostex's traditional flat-surface drive type diaphragm
RP (Regular Phase) headphones with Fostex's traditional flat-surface drive diaphragm.
The sound to the unique, and beyond
The RPKIT50 is a flat-surface drive type diaphragm employing Fostex’s traditional RP (Regular Phase) technology. The RPKIT50, equipped with this historic diaphragm, is available in three types: T50RPmk3 (semi-open type), T40RP (sealed type) and T20RP (open type), which were previously sold as the mk3 series, and T60RP, which has a wood housing and has been adjusted for listening specifications. The T60RP is a headphone assembly kit that allows you to enjoy balanced connection with a connector specially designed for this model, which has been adjusted for listening specifications, and also allows you to adjust the sound to your liking with specialized parts.
TECHNOLOGY
Give a "natural" presentation of musical sound
What is RP [Regular Phase] Technology
RP Technology 1st Generation (1974-)
Foster Electric was the first company in Japan to commercialize a full-surface drive transducer named the RP method, which stands for “Regular Phase” (a surface drive system that operates all surfaces of the diaphragm in regular phase). The RP method is an authentically named method of full-surface drive electroacoustic transducer technology using a flat-surface coil diaphragm. The first RP diaphragm consists of a polyimide film with a snaked aluminum conductor pattern and a repulsive magnetic circuit of samarium-cobalt magnet. This innovative technology combines the advantages of the electrostatic type with the superior performance of the dynamic type to produce natural sound quality with excellent characteristics such as sharp resolution, wide dynamic range, and excellent transient response with low distortion.
RP Technology 2nd Generation (1975-)
The Japanese-made second-generation RP diaphragm is compact and lightweight, with specifications designed for professional use. The magnetic circuit uses a circular isotropic ferrite material and a spiral-shaped printed coil of aluminum foil deposited on a polystyrene membrane diaphragm to efficiently extend the bandwidth and achieve a perfect balance between subtle high and tight bass reproduction, In the 1980s, the T20 and other models using this second-generation RP diaphragm were used as reference models in many studios and helped famous musicians to create their masterpieces, as can still be seen in music videos of the time.
RP Technology 3rd Generation (1998-)
And the third generation used in the RPKIT50. In the late 1990s, ten years after the release of the second-generation RP diaphragm-equipped model, which had established its position as a studio reference in the US and other countries, the development team of the time was tasked with the redevelopment of a new RP monitor headphone. The third generation RP diaphragm, which was developed by the development team at that time, has been highly regarded by engineers and headphone enthusiasts around the world as a model of flat surface diaphragm technology. The so-called “RP sound”, which is recognizable from the conventional dynamic type, is a world-class quality that Fostex has cultivated through the development of speaker units, It is a patented technology that produces a reference sound that carries on the Fostex-ism, and has been passed on to the next generation.
Copper foil etching on a base material of heat-resistant polyimide film
This third generation uses a zigzag shaped printed coil (equivalent to a voice coil) pattern, which allows for equal movement in both vertical and horizontal directions, increasing the amount of information, especially in the mid-high range, and providing superior reproduction of realistic vocals and other sounds. In addition, the use of copper foil as the material for the printed coil has realized high input resistance and further improved sound quality. In addition, polyimide, which is known for its high heat resistance, is used as the base film material. This gives the headphones the high input resistance that is essential for professional headphones.
magnetic circuit
One of the features of the RP-type magnetic circuit is that “a large effective magnetic flux density is obtained by repelling the upper and lower magnets, and the diaphragm is sandwiched between them. This makes it possible for the RP-type magnetic circuit to “obtain a magnetic flux density distribution symmetrical to the direction of vibration of the diaphragm” and succeeds in achieving overwhelming linearity. In addition, the use of six “neodymium rod magnets” has succeeded in obtaining a larger magnetic flux density and a significant improvement in efficiency.
SOUND CUSTOMIZE
The RPKIT50 can be used as a monitor headphone or a listening headphone.
Customize the RPKIT50 to suit your use and preferences.
The RPKIT50 is an assembly kit equipped with the third generation RP diaphragm, which has been used by recording studio engineers and headphone enthusiasts around the world for nearly a quarter of a century. The RPKIT50 is an assembling kit equipped with the third generation RP diaphragm, which has been continuously developed.
Customize your own unique sound
The tuning table above shows the main sound quality changes and features depending on the selected parts. Please refer to the table and consider the combination of the parts while assembling your system.
RPKIT50 is packaged with earpads, dampers, and baffles attached to the main unit to give you an idea of the finished product and how to attach and remove the earpads and baffles. Let’s tune the earpads, dampers, and baffles after removing them while imagining how they will look when installed.
Install sound absorbing material in housing and baffle
Along with the RP diaphragm shape, the protruding sliders on the left and right sides of the RP series and the professional-looking, rugged design of the housing are recognized around the world as icons of the RP series. The RPKIT50’s housing is made of the same material and design as the mk3 series, plastic. mk3 series speakers did not use sound absorbing material on the inside of the housing or a vibration dampening and sound absorbing material on the baffle, but this was adjusted when the mk3 was developed as a feature to increase resolution. The RPKIT50 is a compact, high-frequency amplifier with a high resolution, and is designed to be used in a wide range of applications, including the audio equipment used in the RPKIT50. In this RPKIT50, in order to suppress this image and to adjust the base sound quality to a flatter level, we ask you to start by attaching all the seal-type sound absorbing materials for the housing and the vibration-damping and sound-absorbing materials for the baffle. Of course, after listening to the completed product, you can also enjoy the sound quality without applying the sealed materials if you like, so we recommend that you keep the backing paper.
Install RP driver unit in baffle
Next, place a gasket (cushioning material) on the baffle plate as shown in the image, place the RP driver unit on it, and fix it firmly with screws (3 points).
Installation of tuning components inside the housing
The sound quality of headphones and speakers is greatly influenced by the performance of the driver unit, or diaphragm, and the difference in sound quality is the basis for the characteristics of each model, each manufacturer, and even the direction of the audio brand. The next step is to directly customize the driver unit, which is only possible with the RP diaphragm, a driver unit with a unique shape. A small damper is provided to regulate the ventilation of the driver unit, and the presence or absence of this damper determines the base sound quality. In speakers and headphones, adjusting the volume of the low frequencies can make a big difference in how the midrange and high frequencies sound. These small dampers can be used to adjust the amount of low-frequency frequencies, and when installed, they have the effect of reducing low-frequency frequencies. We recommend that you first listen to a song or instrument you like and adjust the sound to your liking without the headphones installed. Next, install the tuning sheet for the housing, which determines the direction of the headphones. You can choose from three different types: a semi-open type if you use the non-woven fabric type with moderate air permeability, a sealed type to stop air leakage if you use the PET material, or an open type if you do not attach any sheet. You can also enjoy the effects of each of the three types, so please refer to the table below and choose the sound quality you prefer.
Install driver unit (soldering)
Next, solder the wires to the driver unit. ＋The + wire will be colored red (Black or White) and the – cable will be colored red (Red or White), so please follow the printed instructions for soldering and wiring. Please make sure to set the soldering iron at a temperature not exceeding 360 degrees Celsius and try to wire the cable within 5 seconds, preferably 3 seconds. Please be sure to carry out the following instructions with the utmost caution as it may melt the pattern on the diaphragm.
Installation of tuning damper and ear pads for baffle
Finally, the baffles are installed in the reverse order of removal, the baffle dampers are selected and installed, and the ear pads are selected and installed to complete the process. The baffle damper is available in two types, a high-density damper and a low-density damper, which can be used to adjust the amount of airflow through the baffle surface to change the sound quality. The ear pads are also available in two types, a standard synthetic leather type (same specifications as T60RP) and a velour type, which allows for final adjustment of the sound quality. In addition, the earpads for T50RPmk3 can be selected at the time of purchase, so if you use them as monitor headphones, you can further widen the range of sound quality adjustment if you purchase them together with the T50RPmk3.
Balanced connection supported
RPKIT50 supports balanced connection. Two types of cables are included as standard: Φ2.5 → Φ3.5 (2m) for unbalanced connection and Φ2.5 → Φ2.5 (1.2m) for balanced connection, so you can enjoy different sound quality depending on the connection method. High quality OFC conductor is used for the material to realize high resolution and crisp sound in all bands.
RP Technology 1st Generation (1974-)
Foster Electric was the first company in Japan to commercialize a full-surface drive transducer named the RP method, which stands for “Regular Phase” (a surface drive system that operates all surfaces of the diaphragm in regular phase). The RP method is an authentically named method of full-surface drive electroacoustic transducer technology using a flat-surface coil diaphragm. The first RP diaphragm consists of a polyimide film with a snaked aluminum conductor pattern and a repulsive magnetic circuit of samarium-cobalt magnet. This innovative technology combines the advantages of the electrostatic type with the superior performance of the dynamic type to produce natural sound quality with excellent characteristics such as sharp resolution, wide dynamic range, and excellent transient response with low distortion.
RP Technology 2nd Generation (1975-)
The Japanese-made second-generation RP diaphragm is compact and lightweight, with specifications designed for professional use. The magnetic circuit uses a circular isotropic ferrite material and a spiral-shaped printed coil of aluminum foil deposited on a polystyrene membrane diaphragm to efficiently extend the bandwidth and achieve a perfect balance between subtle high and tight bass reproduction, In the 1980s, the T20 and other models using this second-generation RP diaphragm were used as reference models in many studios and helped famous musicians to create their masterpieces, as can still be seen in music videos of the time.
RP Technology 3rd Generation (1998-)
And the third generation used in the RPKIT50. In the late 1990s, ten years after the release of the second-generation RP diaphragm-equipped model, which had established its position as a studio reference in the US and other countries, the development team of the time was tasked with the redevelopment of a new RP monitor headphone. The third generation RP diaphragm, which was developed by the development team at that time, has been highly regarded by engineers and headphone enthusiasts around the world as a model of flat surface diaphragm technology. The so-called “RP sound”, which is recognizable from the conventional dynamic type, is a world-class quality that Fostex has cultivated through the development of speaker units, It is a patented technology that produces a reference sound that carries on the Fostex-ism, and has been passed on to the next generation.
Copper foil etching on a base material of heat-resistant polyimide film
This third generation uses a zigzag shaped printed coil (equivalent to a voice coil) pattern, which allows for equal movement in both vertical and horizontal directions, increasing the amount of information, especially in the mid-high range, and providing superior reproduction of realistic vocals and other sounds. In addition, the use of copper foil as the material for the printed coil has realized high input resistance and further improved sound quality. In addition, polyimide, which is known for its high heat resistance, is used as the base film material. This gives the headphones the high input resistance that is essential for professional headphones.
magnetic circuit
One of the features of the RP-type magnetic circuit is that “a large effective magnetic flux density is obtained by repelling the upper and lower magnets, and the diaphragm is sandwiched between them. This makes it possible for the RP-type magnetic circuit to “obtain a magnetic flux density distribution symmetrical to the direction of vibration of the diaphragm” and succeeds in achieving overwhelming linearity. In addition, the use of six “neodymium rod magnets” has succeeded in obtaining a larger magnetic flux density and a significant improvement in efficiency.
SOUND CUSTOMIZE
Customize the RPKIT50 to suit your use and preferences.
The RPKIT50 is an assembly kit equipped with the third generation RP diaphragm, which has been used by recording studio engineers and headphone enthusiasts around the world for nearly a quarter of a century. The RPKIT50 is an assembling kit equipped with the third generation RP diaphragm, which has been continuously developed.
Customize your own unique sound
The tuning table above shows the main sound quality changes and features depending on the selected parts. Please refer to the table and consider the combination of the parts while assembling your system.
RPKIT50 is packaged with earpads, dampers, and baffles attached to the main unit to give you an idea of the finished product and how to attach and remove the earpads and baffles. Let’s tune the earpads, dampers, and baffles after removing them while imagining how they will look when installed.
Install sound absorbing material in housing and baffle
Along with the RP diaphragm shape, the protruding sliders on the left and right sides of the RP series and the professional-looking, rugged design of the housing are recognized around the world as icons of the RP series. The RPKIT50’s housing is made of the same material and design as the mk3 series, plastic. mk3 series speakers did not use sound absorbing material on the inside of the housing or a vibration dampening and sound absorbing material on the baffle, but this was adjusted when the mk3 was developed as a feature to increase resolution. The RPKIT50 is a compact, high-frequency amplifier with a high resolution, and is designed to be used in a wide range of applications, including the audio equipment used in the RPKIT50. In this RPKIT50, in order to suppress this image and to adjust the base sound quality to a flatter level, we ask you to start by attaching all the seal-type sound absorbing materials for the housing and the vibration-damping and sound-absorbing materials for the baffle. Of course, after listening to the completed product, you can also enjoy the sound quality without applying the sealed materials if you like, so we recommend that you keep the backing paper.
Install RP driver unit in baffle
Next, place a gasket (cushioning material) on the baffle plate as shown in the image, place the RP driver unit on it, and fix it firmly with screws (3 points).
Installation of tuning components inside the housing
The sound quality of headphones and speakers is greatly influenced by the performance of the driver unit, or diaphragm, and the difference in sound quality is the basis for the characteristics of each model, each manufacturer, and even the direction of the audio brand. The next step is to directly customize the driver unit, which is only possible with the RP diaphragm, a driver unit with a unique shape. A small damper is provided to regulate the ventilation of the driver unit, and the presence or absence of this damper determines the base sound quality. In speakers and headphones, adjusting the volume of the low frequencies can make a big difference in how the midrange and high frequencies sound. These small dampers can be used to adjust the amount of low-frequency frequencies, and when installed, they have the effect of reducing low-frequency frequencies. We recommend that you first listen to a song or instrument you like and adjust the sound to your liking without the headphones installed. Next, install the tuning sheet for the housing, which determines the direction of the headphones. You can choose from three different types: a semi-open type if you use the non-woven fabric type with moderate air permeability, a sealed type to stop air leakage if you use the PET material, or an open type if you do not attach any sheet. You can also enjoy the effects of each of the three types, so please refer to the table below and choose the sound quality you prefer.
Install driver unit (soldering)
Next, solder the wires to the driver unit. ＋The + wire will be colored red (Black or White) and the – cable will be colored red (Red or White), so please follow the printed instructions for soldering and wiring. Please make sure to set the soldering iron at a temperature not exceeding 360 degrees Celsius and try to wire the cable within 5 seconds, preferably 3 seconds. Please be sure to carry out the following instructions with the utmost caution as it may melt the pattern on the diaphragm.
Installation of tuning damper and ear pads for baffle
Finally, the baffles are installed in the reverse order of removal, the baffle dampers are selected and installed, and the ear pads are selected and installed to complete the process. The baffle damper is available in two types, a high-density damper and a low-density damper, which can be used to adjust the amount of airflow through the baffle surface to change the sound quality. The ear pads are also available in two types, a standard synthetic leather type (same specifications as T60RP) and a velour type, which allows for final adjustment of the sound quality. In addition, the earpads for T50RPmk3 can be selected at the time of purchase, so if you use them as monitor headphones, you can further widen the range of sound quality adjustment if you purchase them together with the T50RPmk3.
Balanced connection supported
RPKIT50 supports balanced connection. Two types of cables are included as standard: Φ2.5 → Φ3.5 (2m) for unbalanced connection and Φ2.5 → Φ2.5 (1.2m) for balanced connection, so you can enjoy different sound quality depending on the connection method. High quality OFC conductor is used for the material to realize high resolution and crisp sound in all bands.
RPKIT50 supports balanced connection. Two types of cables are included as standard: Φ2.5 → Φ3.5 (2m) for unbalanced connection and Φ2.5 → Φ2.5 (1.2m) for balanced connection, so you can enjoy different sound quality depending on the connection method. High quality OFC conductor is used for the material to realize high resolution and crisp sound in all bands.
Specifications
Main Specifications
| model (e.g. of a vehicle) | RP dynamic type |
|---|---|
| Playback frequency band | 15 to 35,000 Hz |
| impedance | 50Ω |
| sensitivity | 89~92dB/mW |
| Maximum input | 3,000mW |
| Mass of main unit | Approx. 385g (in case of standard specifications / cord not included) |
| Accessories (cable length) | Synthetic leather ear pads (2 pairs / velour type pre-installed) ・RP driver unit (1 pair) |
*When using headphones, please refrain from using them for long periods of time and use them at a moderate volume so as not to irritate your ears.