Based on the RS ONE, RS THREE further leverages the technology of the flagship HS series to create a sound suitable for music production. The compact, lightweight and fatigue-free design of the RS THREE provides a comfortable monitoring environment that you can carry with you anywhere. On the practical side, the small body of the RS THREE can be worn by anyone, while the robust design avoids common failure points that lead to broken nozzles, broken connectors and housing parts, and poor cable contact. Furthermore, the cable has been improved to a length that is easy to handle in studios and other locations, with less tangling and less touch noise.

In the planning of RS THREE, Acoustune interviewed a number of well-known professional composers. Acoustune found that many of them use multiple environments (speakers, headphones and earphones) when creating music. When they delved into what is required of earphones in areas that are different from speakers and headphones, it was determined that high performance is critical in areas such as ultra-low frequencies, soft sounds, lip sounds and panning. The RS THREE is tailored to make these sounds easier to hear while also providing balanced audio. Whether used on its own or in conjunction with speakers and headphones, RS THREE enhance your music production workflow with high performance audio.

The Myrinx EL-S used in the RS THREE is based on the Myrinx EL used in the RS ONE, but with a more tightly controlled diaphragm for more accurate reference monitoring. The material used for the Myrinx EL-S is an ultra-high performance resin that is used in medical applications, yet is lightweight, extremely rigid and boasts extremely high acoustic performance with high internal loss. The high internal loss reduces extraneous incidental sounds that adversely affect the sense of air and localisation, and enables the fine monitoring of sound fields and panning required by modern high-resolution sound sources.

In order to make the most of this Myrinx EL-S driver, the RS THREE features a large back cavity behind the diaphragm. The distance from the diaphragm to the grille has been designed to achieve a high input resistance that allows normal use even after a momentary sine wave input of up to 250 mW of signal. This gives the earphones' speakers a robustness that prevents them from breaking even in the event of a sudden large input. The diaphragm's large stroke width brings out the bass as if it were a loudspeaker, providing the quality monitoring required by recent music.

Acoustune has minimised the number of parts in the RS THREE and thoroughly researched the most fragile parts of earphones to create a highly robust body.

The housing consists of two parts made of polycarbonate, which is highly resistant to impact, weather, and heat. By reducing the number of parts as much as possible, Acoustune has achieved simplicity and increased the rigidity of each part, greatly reducing the risk of failure even in harsh environments. The face plate part plays a role in increasing the rigidity of the body while giving it an identity as an ear-monitor. In addition, the small size of the housing design makes it suitable for a wider variety of ear shapes.

The new Pentaconn Ear cable connector used in the RS ONE is designed and manufactured by Nippon DICS Corporation and boasts high sound quality and reliability. Compared to conventional MMCX connectors, the plug and jack portions are in closer contact, resulting in superior conduction performance. It is also easier to attach and detach, and more robust.

The 'ARM011L' cable included with the RS ONE uses high-purity Litz wire and Kevlar wire braided together, and is covered with PU material to make it easier to manage. Compared to other connectors, the Pentaconn Ear connector reduces the risk of contact failure due to wear and sweat caused by connection and disconnection, and offers high reliability, reducing the risk of accidents in production environments.

The RS THREE has a longer 1.8 m long cable designed for ease of use with production consoles. A 6.3 mm stereo standard plug conversion adapter is also included.

Three sizes (S/M/L) of AET07 eartip are included with the RS THREE. The AET07 is used as the standard reference eartip for Acoustune earphones. A pair of AET02 foam eartips is also included for a sealed feel that only foam tips can provide.