Introducing Solo

Redefining the meaning of “full-range sound” in portable high-end audio, Solo expertly covers the entire sonic spectrum with a single planar driver. The final note in our legendary tia™ line of UIEMs has been years in the making. Staying true to the tech-disruptive legacy of Fourté, Trio, and Duo, we looked to the past for innovative solutions to the modern challenge of tuning a single driver. In addition to a traditional electronic filter that subtly shifts the tonal balance, we have introduced the world’s first Helmholtz resonator in an IEM.

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The 14.2mm planar driver’s acoustic chamber integrates two Helmholtz resonators, meticulously tuned to acoustically sculpt its frequency response. This chamber is also engineered to include our apex core design, expertly relieving pneumatic pressure and enhancing the sense of physical space to a degree never before experienced in a single-driver IEM. Combined with our patented LID technology, all of these innovations are housed in our most striking design update since the introduction of Fourté in 2016. These elements unite to deliver a sound that is quintessentially 64 Audio, combining the exceptionally detailed transient response of planar technology with an unexpectedly robust low-frequency presence.

64 Audio Solo Universal In-Ear Monitor Wireframe

As our first single-driver UIEM, Solo achieves what Fourté did in 2016 when we simultaneously unveiled the world’s first 18-driver IEM and offered a four-driver alternative that arguably provided more sonic resolution. By accomplishing this with a single driver, we open a new realm of possibilities in micro-acoustic design.

Planar Magnetic Driver

The planar magnetic driver features a flat diaphragm with embedded conductors suspended between two sets of magnets, unlike traditional dynamic drivers that utilize a conical diaphragm driven by a voice coil. Because the entire diaphragm moves uniformly due to the planar magnetic field, we can deliver the detail and micro-transient information that would typically require a dedicated high-frequency driver. Since the diaphragm isn’t driven by a voice coil attached to a cone, which can cause uneven movement, we can reliably extract a true high-resolution full-range sound from this single driver.

64 Audio Solo Universal In-Ear Monitor Planar Driver

Helmholtz Resonators

While planar magnetic technology has been present in portable hi-fi for many years, we wanted to truly showcase its potential in our products. To offer a new perspective on this technology, we needed a combination of a slight but broad reduction in high-frequency amplitude and the attenuation of a few very narrow frequency bands. As the electronic filter acts as a very subtle reductive shelf, we had to think creatively to effectively control some problematic frequencies. For this, we drew on our years of research into Helmholtz resonators, an acoustic device from the mid-19th century. The two micro-cavities, 3D printed into Solo’s sound chamber, operate by forcing air in and out, causing the air inside to resonate at a specific frequency. By precisely determining the dimensions of the cavity and its neck, we can target a very narrow resonant frequency to amplify or diminish.

LID®

Linear Impedance Design (LID) is a patented circuit that compensates for the non-linear electrical resistance resulting from Solo’s electronic shelf filter. Variations in source amplifier output impedance in devices like smartphones, body packs, DAC/amps, and DAPs typically lead to changes in frequency response. LID restores proper interaction with the source, preserving the intended sound signature and ensuring consistent, reliable performance.

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Apex® Core

Adding to our list of innovations, we implement our patented pressure-relieving technology in the form of apex core, elevating this design to new levels of fidelity and spatial acuity. Because Solo’s acoustic chamber includes our integrated apex core technology, we achieve a similar fit and comfort to that of the Duo. The design offers just enough isolation to allow the listener to focus on the audio while feeling so unoccluded that you may initially wonder if you have a proper seal. This ensures hours of comfortable listening, made possible by our patented technology.

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Sound

Being a 64 Audio product demands adherence to strict standards of accuracy, musicality, and balance while also offering something unique enough to earn a place among our legendary lineup of UIEMs. The scale to which Solo fulfills this is magnified by the fact that it employs a completely new speaker technology for us, achieving it all with a single driver per side. The agile performance expected of a planar driver achieves maximum realism by extracting subtle details in the music. These transients emerge from the mix, seamlessly keeping pace with your focus on the primary elements of the song. Our acoustic notch filters are strategically placed to eliminate sharpness without compromising driver performance. Apex core assists the high-mid and high frequencies in creating a vast sonic landscape, even in very complex mixes. Alongside this realism comes a tactile immersion in the textures of instruments and even the sonic characteristics of the recording equipment used in your favorite tracks. By intentionally shaping the overall response of Solo, we achieve a bass that has substantial impact and deep sub-bass presence.

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Copper Eight-Braid Cable

Solo is being paired with our first pure copper cable. The OCC Copper, which is 23 x 25 AWG wires, is built into eight braids with a pleasant tactile feel as well as an impressively low 0.26Ω impedance rating. Solo comes standard with two of these cables, one 3.5mm single-ended and one balanced 4.4mm.

64 Audio Solo Universal In-Ear Monitor Copper Cable

IN THE BOX

Carry Case
Foam + Silicone Ear Tips
2-Pin Cables
Cleaning Tool
Cleaning Cloth
Shirt Clip

SPECIFICATIONS

TRANSDUCER TYPE: 14.2 mm Planar Magnetic Driver
FREQUENCY RESPONSE: 20 Hz – 20 kHz
SENSITIVITY: 100 dB/mW @1kHz
IMPEDANCE: 16 Ω @1kHz
ISOLATION: -12 dB
CABLES: 3.5MM + 4.4MM
Cable Material: OCC Copper
Cable Structure: 25 AWG + 23 Wires

64 Audio Solo Universal Planar Magnetic In-Ear Monitor (Pre-Order)