Binary Acoustics / EP321-MEMS

The "EP321-MEMS" is an earphone equipped with a hybrid driver system (2DD + 3BA + 1MEMS) that delivers a powerful, natural sound.

■ High-Performance Driver Configuration
The EP321 features a sophisticated driver array—comprising one dynamic driver, one passive diaphragm, three balanced armature (BA) drivers, and a direct-drive MEMS unit—to deliver a sound that is powerful, natural, and vivid. A physical 3-way crossover network optimizes each frequency band, resulting in an expansive dynamic range, rich high-frequency detail, transparent midrange, and an overall sound that is powerful, full-bodied, and natural.

■ High Resolution, High Responsiveness, and Exceptional Versatility
Typically, MEMS devices require a dedicated amplifier to provide the necessary bias voltage for operation. The Binary EP321 utilizes an innovative direct-drive MEMS unit, allowing it to be driven directly from standard playback devices without the need for an external amplifier. Furthermore, because the MEMS unit employs an ultra-rigid, thin, and lightweight semiconductor-based diaphragm, the EP321 achieves remarkable high-frequency resolution, rapid response, and excellent extension.

■ Powerful Detail, Rich Tonal Quality, and Intricate Expression
By combining a composite high-frequency BA driver unit with a MEMS unit, the EP321 delivers a clearer, higher-resolution sound. It excels at reproducing the unique tonal characteristics of various musical instruments while maintaining clear separation and overall balance, allowing the listener to experience a wealth of intricate detail.

■ The EP321 incorporates a full-range BA driver dedicated to the midrange, ensuring a seamless and cohesive presentation across the mid-frequency spectrum.
It reproduces the distinct vocal qualities of different singers with high fidelity, clearly conveying the emotional nuances of vocal-driven music. ■ Active + Passive Hybrid Low-Frequency Driver
The low-frequency section of the EP321 utilizes the same 10mm dynamic driver and 6mm wool-paper-cone passive radiator found in the highly acclaimed DynaQuattro. Featuring an active-plus-passive hybrid low-frequency module with a dual-magnet circuit, the EP321 delivers a powerful low-end response while remaining comfortable for long listening sessions, ensuring minimal listener fatigue.

■ Striking Design with a Lightweight Shell
The faceplate of the EP321 features irregular geometric elements that refract light differently depending on the viewing angle, creating a dynamic, multi-colored reflection. Crafted from high-quality stainless steel using precision CNC machining, the EP321 remains remarkably lightweight—weighing only about 7.5g per earpiece—despite its stainless steel construction.

■ High-Precision 3D-Printed Shell for Ergonomic Comfort
The ear shell of the EP321 was developed in collaboration with the renowned 3D-printing service provider, HeyGears.
Utilizing high-precision 3D-printing technology, the shell incorporates a pre-calculated internal acoustic structure. The Binary EP321 is designed to provide an exceptionally comfortable fit for the user.

■ High-Quality Included Eartips
The EP321 comes with six pairs of eartips (two sets of three different sizes), making them easy to fit. You can also experiment with your own preferred eartips to further customize your listening experience.

■ Easily Swappable Cable with Universal Connectors
The EP321 includes an oxygen-free, silver-plated copper cable that ensures clean audio signal transmission. The cable uses a standard 0.78mm 2-pin connector, with clear "L" and "R" markings on the inside to make identifying the left and right channels simple.
■ Driver Configuration: 2DD + 3BA + 1 MEMS (10mm dynamic driver for low frequencies + 6mm passive diaphragm + 3 balanced armature drivers + MEMS driver)
■ Cable/Plug: 0.78mm 2-pin interface, 4.4mm plug
■ Sensitivity: 122dB/Vrms (@1kHz)
■ Impedance: 13Ω (@1kHz)
■ Frequency Response: 8Hz–40kHz (1/4-inch free-field, -3dB)
■ Total Harmonic Distortion (THD): <1% (@1kHz)
■ Enclosure: 3D-printed resin shell with a CNC-machined stainless steel faceplate
■ Included Accessories: EP321 earphones (1 pair, left/right), high-purity stock cable (0.78mm 2-pin), carrying case, 2 sets of ear tips, user manual