Welcome to "yamaguchi munehisa com"
This custom-fit car speaker system is the realization of his passion for integrating his love for cars and music into a seamless audio experience. Designed with precision and care, it delivers exceptional sound quality that enhances every drive.
ND Roadster speaker system, MAZDA
ND Roadster Speaker System Version 2 – Reference Pricing
・Front Speaker System $1,600 USD
・KAI Subwoofer Ver.2 (core charge required) $650 USD
・BassPLUS+ (per seat) $260 USD
・ND Roadster 3D System (includes DSP tuning data) $290 USD
All prices are excluding tax.
For system configurations that include power amps and other components, please contact us. We will propose a system based on your musical preferences and vehicle usage.The USD prices are reference amounts and will be regularly updated to reflect exchange rate fluctuations.
・Front Speaker System $1,600 USD
・KAI Subwoofer Ver.2 (core charge required) $650 USD
・BassPLUS+ (per seat) $260 USD
・ND Roadster 3D System (includes DSP tuning data) $290 USD
All prices are excluding tax.
For system configurations that include power amps and other components, please contact us. We will propose a system based on your musical preferences and vehicle usage.The USD prices are reference amounts and will be regularly updated to reflect exchange rate fluctuations.
The ND Roadster Speaker System was created with one goal in mind: to deliver an overwhelming audio experience.
It all began in March 2018, at a listening session for our newly completed speaker system for the NA Roadster. An ND Roadster owner attended and passionately asked us to develop a version for his car with the same kind of sound. That heartfelt request became the spark that ignited this project.
The ND Roadster represents a new era of sports cars. Many owners have already equipped theirs with the factory-installed BOSE sound system. But we believed that a speaker system offering only a moderate improvement would serve no real purpose. From the outset, our aim was clear: to create something that instantly captivates the listener—a sound that transforms the thrill of open-air driving in the ND into something on another level entirely.
After a year of development, Version 1 was born. Two years later, Version 2 followed, delivering even greater clarity, nuance, and power.
Our lineup includes the KAI (魁) Subwoofer, custom-built using the factory BOSE subwoofer housing, the BassPLUS+ unit that dramatically enhances low-frequency perception even during top-down driving, and the ND-3D Sound System (patent pending), which projects the sound image forward—floating in front of the listener rather than staying trapped on a flat screen. To drive it all, we offer a range of specially designed power amplifier kits. Each of these components was engineered to take the ND Roadster’s music experience into a whole new dimension.
We’ve included a short introductory video below that explains the ND Roadster Speaker System in more detail. It runs about 10 minutes, with the music sample beginning around the 8:50 mark. While it’s impossible to fully convey the depth of the 3D system or the body-shaking effect of BassPLUS+ through video, if you find yourself drawn to the lifelike edge of each instrument or the deep, resonant sound of the drums, then chances are our musical sensibilities align.
Whatever you choose to listen to, we believe you’ll be more than satisfied.
For the best experience, we highly recommend using high-quality headphones.
【ND Roadster yamaguchi speaker system DEMO】
We've organized the different system combinations into a configuration chart. Please refer to the chart along with the detailed descriptions. For listening sessions, questions, or to place an order, please scroll to the bottom of this page and click the button:
★ How to Order the Speaker System
It all began in March 2018, at a listening session for our newly completed speaker system for the NA Roadster. An ND Roadster owner attended and passionately asked us to develop a version for his car with the same kind of sound. That heartfelt request became the spark that ignited this project.
The ND Roadster represents a new era of sports cars. Many owners have already equipped theirs with the factory-installed BOSE sound system. But we believed that a speaker system offering only a moderate improvement would serve no real purpose. From the outset, our aim was clear: to create something that instantly captivates the listener—a sound that transforms the thrill of open-air driving in the ND into something on another level entirely.
After a year of development, Version 1 was born. Two years later, Version 2 followed, delivering even greater clarity, nuance, and power.
Our lineup includes the KAI (魁) Subwoofer, custom-built using the factory BOSE subwoofer housing, the BassPLUS+ unit that dramatically enhances low-frequency perception even during top-down driving, and the ND-3D Sound System (patent pending), which projects the sound image forward—floating in front of the listener rather than staying trapped on a flat screen. To drive it all, we offer a range of specially designed power amplifier kits. Each of these components was engineered to take the ND Roadster’s music experience into a whole new dimension.
We’ve included a short introductory video below that explains the ND Roadster Speaker System in more detail. It runs about 10 minutes, with the music sample beginning around the 8:50 mark. While it’s impossible to fully convey the depth of the 3D system or the body-shaking effect of BassPLUS+ through video, if you find yourself drawn to the lifelike edge of each instrument or the deep, resonant sound of the drums, then chances are our musical sensibilities align.
Whatever you choose to listen to, we believe you’ll be more than satisfied.
For the best experience, we highly recommend using high-quality headphones.
【ND Roadster yamaguchi speaker system DEMO】
We've organized the different system combinations into a configuration chart. Please refer to the chart along with the detailed descriptions. For listening sessions, questions, or to place an order, please scroll to the bottom of this page and click the button:
★ How to Order the Speaker System
①This is the simplest setup: replacing only the front speakers (tweeters and door speakers) in cars with “Segment Audio” or “Mazda Connect (without BOSE).”
Installation is technically possible, but the Yamaguchi speaker system is designed to work with a subwoofer, so this setup is not recommended.
②Cars with the BOSE sound system come with a factory subwoofer and a dedicated power amplifier. This setup upgrades the front speakers (tweeters and door speakers) while keeping the factory BOSE components. Experience the joy of rediscovering new details in your favorite songs every time you drive. Another benefit: even at high volume, the door panels won’t resonate, so sound leakage is greatly reduced. Please note that installation fees are not included and will be charged separately.
③If your car has the BOSE sound system with a built-in subwoofer power amp, you can enjoy the Yamaguchi speaker system together with the KAI subwoofer―no additional Power Amp. KIT required. The KAI subwoofer eliminates the muddy resonance caused by box and port noise, a common issue in factory subwoofers. As a result, the speaker system delivers even clearer, more defined sound. Please note that installation fees are not included and will be charged separately.
④This is the most basic setup using a Power Amp. KIT. It frees your music from the heavy preset EQ curve of the BOSE power amp. The kit with the SR4.500 amp installs on the left side of the trunk. The kit with the AF M4D amp can be installed in several locations: the center storage box, left, center, or right side behind the trunk trim. Both amps use 4 channels as 3 (see chart), so BassPLUS+ cannot be added. This is the best basic setup for enjoying the speaker system and KAI subwoofer in cars with “Segment Audio” or “Mazda Connect (without BOSE).” Please note that installation fees are not included and will be charged separately.
⑤The combination of the speaker system, KAI subwoofer, and BassPLUS+ transforms your music into an emotional experience―something many people have never felt before through an ND audio system. If you don’t need DSP or high-res sources but still want to unlock the full potential of the ND speaker system, this is the setup for you. The Power Amp. KIT with the SR5.600 can be installed on the left side of the trunk. The kit with the AF M6D amp can be mounted in various locations: the center storage box or the left, center, or right side behind the trunk trim. Please note that installation fees are not included and will be charged separately.
⑥The true advantage of choosing the DSP Power Amp. KIT lies in tailoring your audio environment to match your musical taste and driving style. While features like time alignment are often highlighted―positioning the sound image right in front of you―that’s just one of many capabilities. What really matters is understanding the presence and personality of the Roadster, knowing what kind of sound the owner loves, and blending these elements through DSP tuning backed by musical knowledge and real experience. This system powers everything (except the 3D system) with strength and clarity. It also comes preloaded with six custom sound presets. The DSP Power Amp. KIT using the AF M8.14bit amp can be installed in any of the following: center storage box, left, center, or right trunk interior. This is the only setup that allows a full upgrade to the 3D system (⑦) without replacing any components. Please note that installation fees are not included and will be charged separately.
⑦The Roadster 3D system―currently patent pending―brings a whole new level of excitement, without any cutting or modifications to your car. Keeping the factory interior and exterior design completely intact, it creates a stunning effect: stereo imaging across the windshield, with vocals and lead instruments floating vividly in front of you. This is achieved through advanced DSP tuning, tailored to factors like roof type (soft/hard), seat position, and listening environment. It even delivers what was once considered impossible in a car: the powerful resonance of a full orchestra in a concert hall, or the immersive excitement of a modern movie theater in Cinema Mode. The DSP Power Amp. KIT includes an 8-channel DSP amplifier (AF C8.14bit or AF M8.14bit) and a dedicated mono amp for the subwoofer (AF M1D). You can install the two units in any combination of two locations: center storage, or left/center/right trunk interior. Among the two DSP amps, the AF M8.14bit stands out not only for its output power, but also for its smooth, analog-like sound quality, reminiscent of classic high-end amplifiers. Please note that installation fees are not included and will be charged separately.
②Cars with the BOSE sound system come with a factory subwoofer and a dedicated power amplifier. This setup upgrades the front speakers (tweeters and door speakers) while keeping the factory BOSE components. Experience the joy of rediscovering new details in your favorite songs every time you drive. Another benefit: even at high volume, the door panels won’t resonate, so sound leakage is greatly reduced. Please note that installation fees are not included and will be charged separately.
③If your car has the BOSE sound system with a built-in subwoofer power amp, you can enjoy the Yamaguchi speaker system together with the KAI subwoofer―no additional Power Amp. KIT required. The KAI subwoofer eliminates the muddy resonance caused by box and port noise, a common issue in factory subwoofers. As a result, the speaker system delivers even clearer, more defined sound. Please note that installation fees are not included and will be charged separately.
④This is the most basic setup using a Power Amp. KIT. It frees your music from the heavy preset EQ curve of the BOSE power amp. The kit with the SR4.500 amp installs on the left side of the trunk. The kit with the AF M4D amp can be installed in several locations: the center storage box, left, center, or right side behind the trunk trim. Both amps use 4 channels as 3 (see chart), so BassPLUS+ cannot be added. This is the best basic setup for enjoying the speaker system and KAI subwoofer in cars with “Segment Audio” or “Mazda Connect (without BOSE).” Please note that installation fees are not included and will be charged separately.
⑤The combination of the speaker system, KAI subwoofer, and BassPLUS+ transforms your music into an emotional experience―something many people have never felt before through an ND audio system. If you don’t need DSP or high-res sources but still want to unlock the full potential of the ND speaker system, this is the setup for you. The Power Amp. KIT with the SR5.600 can be installed on the left side of the trunk. The kit with the AF M6D amp can be mounted in various locations: the center storage box or the left, center, or right side behind the trunk trim. Please note that installation fees are not included and will be charged separately.
⑥The true advantage of choosing the DSP Power Amp. KIT lies in tailoring your audio environment to match your musical taste and driving style. While features like time alignment are often highlighted―positioning the sound image right in front of you―that’s just one of many capabilities. What really matters is understanding the presence and personality of the Roadster, knowing what kind of sound the owner loves, and blending these elements through DSP tuning backed by musical knowledge and real experience. This system powers everything (except the 3D system) with strength and clarity. It also comes preloaded with six custom sound presets. The DSP Power Amp. KIT using the AF M8.14bit amp can be installed in any of the following: center storage box, left, center, or right trunk interior. This is the only setup that allows a full upgrade to the 3D system (⑦) without replacing any components. Please note that installation fees are not included and will be charged separately.
⑦The Roadster 3D system―currently patent pending―brings a whole new level of excitement, without any cutting or modifications to your car. Keeping the factory interior and exterior design completely intact, it creates a stunning effect: stereo imaging across the windshield, with vocals and lead instruments floating vividly in front of you. This is achieved through advanced DSP tuning, tailored to factors like roof type (soft/hard), seat position, and listening environment. It even delivers what was once considered impossible in a car: the powerful resonance of a full orchestra in a concert hall, or the immersive excitement of a modern movie theater in Cinema Mode. The DSP Power Amp. KIT includes an 8-channel DSP amplifier (AF C8.14bit or AF M8.14bit) and a dedicated mono amp for the subwoofer (AF M1D). You can install the two units in any combination of two locations: center storage, or left/center/right trunk interior. Among the two DSP amps, the AF M8.14bit stands out not only for its output power, but also for its smooth, analog-like sound quality, reminiscent of classic high-end amplifiers. Please note that installation fees are not included and will be charged separately.
