64 Audio’s lineup spans entry-level hybrids to ultra-high-end flagships, with models priced roughly from $349 up to $3599. Each model is tuned for a specific balance of clarity, warmth, and bass, and the most expensive (18-driver) models serve as the company’s studio-reference monitors. Prices and sound signatures vary widely. For example, the 2-driver A2e (~$499) is described as offering “all the accuracy, balance, and comfort you expect from a professional IEM at an affordable price”. Stepping up, the 3-driver A3e ($749) delivers a full-range sound with “capable bass, present mids, and composed highs”, while the 3-driver A3t ($899) is a neutral, reference-grade monitor. These entry-level monitors are used by performers in smaller venues; for instance, James Murphy of LCD Soundsystem reportedly uses the A3t. The universal-fit Aspire series ($349–$799) rounds out this tier as 64 Audio’s most affordable UIEM line (no detailed signature given).

Behind every exceptional 64 Audio IEM lies a trio of proprietary technologies that fundamentally change how in-ear monitors deliver sound to your ears. These innovations not only distinguish 64 Audio from competitors but also address common issues that have plagued IEMs for years.

Tia System: Open Balanced Armature Design

The cornerstone of 64 Audio’s innovation is their Tia (Tubeless In-Ear Audio) system, which allows sound to travel to your ear in a more natural way. Unlike traditional IEMs, Tia eliminates sound-altering tubes and dampers. The complete system consists of three critical elements:

• Open balanced armature drivers that remove the conventional enclosure around the diaphragm
• A single-bore design that reduces tube resonance
• Acoustic chambers that optimize driver performance

By opening the balanced armature design, the diaphragm becomes fully unobstructed, significantly reducing vibrations and resonances common in conventional closed designs. The result is remarkable resolution and transparency across the frequency spectrum. While most 64 Audio models feature at least the tia single-bore and tia high driver, only their flagship models like the Trió and Fourté include all three elements of the complete system.

Apex Modules: Customizable Isolation

Another groundbreaking technology from 64 Audio is their Apex (Air Pressure Exchange) system – a pneumatically interactive vent that releases air pressure in a sealed ear canal. When you insert an IEM, trapped air causes your eardrum to work excessively, leading to listener fatigue. Apex alleviates this pressure, allowing your eardrum to move naturally.

Apex modules come in three variations:

• mX: Provides -10dB isolation, creates the most open, transparent experience
• m15: Offers -15dB isolation with moderate bass attenuation
• m20: Delivers -20dB isolation with maximum low-frequency retention

These interchangeable modules let you customize your listening experience based on your environment and preferences. Each affects not only isolation but also soundstage width and bass response. The technology appears in most 64 Audio models, although flagship models like the Trió and Fourté contain internal apex modules to preserve their acoustic chambers.

LID Circuit: Device-Independent Performance

The third pillar of 64 Audio’s technology suite is LID (Linear Impedance Design), a proprietary circuit that corrects the non-linear impedances of drivers. This ingenious solution addresses a common problem: IEMs sound different depending on the output impedance of the source device.

LID ensures that whether you’re plugged into a smartphone, professional audio interface, or stage monitoring system, your IEMs deliver consistent sound. This becomes particularly valuable for professional musicians who might use various devices during recording, rehearsal, and performance.

The technology appears in most 64 Audio models except the A18t, U18t, and Fourté. For touring professionals who switch between different audio sources, this consistency proves invaluable for maintaining reliable sound quality.

In the $1–1.7K range, 64 Audio offers more drivers and stronger bass. The A4s (4-driver, $1099) is a hybrid CIEM noted for “deep enveloping bass” and “extended airy highs”. Its universal equivalent, the U4s (quad-driver UIEM, $1099), is similarly “balanced and naturally sounding” with a “physically engaging sub-bass”. A stage-oriented 6-driver model, the A6t (custom, $1299), is “a favorite among multi-instrumentalists and audio engineers,” offering “extended highs, smooth mids, defined lower-mids and powerful lows”. Its universal sibling, the U6t (6-driver, $1299), provides a “balanced sound quality” with natural upper-mid imaging that “realistically presents instruments”. Rappers Latin Mafia and Marc Anthony have been seen using the A6t.

Other mid-tier models include the Solo (1-driver planar, $1399). Despite its single-driver design, Solo “covers the entire sonic spectrum with a single planar driver” and employs Helmholtz resonators to shape its tone. 64 Audio notes Solo’s sound combines the “detailed transient response of planar technology with an unexpectedly robust low-frequency presence”, giving it clarity and deep bass. The Nio (9-driver UIEM, $1699) incorporates a dynamic woofer and tia drivers; it boasts extended lows and a rich 3D soundstage, with “smooth treble and natural warmth”. Notably, Pearl Jam’s members have adopted the N8 (custom 9-driver, $1699, co-designed with bassist Nathan East), which delivers a “warm sounding hybrid” signature with “immense bass headroom, saturated lower-mids, smooth mids and detailed highs”.

At about $1999, 64 Audio’s classic studio/athlete monitors appear. The custom A12t (12-driver CIEM) is a balanced reference monitor tuned for stage use: it’s described as “balanced, natural, and musical while being articulate in the upper-mids and punchy in the lows”. This versatility makes the A12t a favorite across genres – pop stars like Maluma and Lady Gaga, rock bands like Metallica and Arcade Fire, rappers like Childish Gambino and Macklemore, and many others use the A12t as their main monitor. The universal U12t (12-driver UIEM, $1999) is essentially the same reference design in a universal shell; it’s called a “jack of all trades” that delivers “immersive sound, impeccable spatial imaging, and reference-level detail”, pleasing both warm-leaning and critical listeners.

Also in this range is the 3-driver universal Trió ($2299): a fully tubeless IEM designed for audiophiles. It’s described as hitting a “sweet spot between reference-level clarity and a smooth sound signature”. Reviewers note that Trió’s sound is “seductive… with excellent body and a mildly warm sound”, making it very enjoyable for long listening. Finally, at $2499, the Volür (10-driver UIEM) ushers in advanced tech: two large dynamic bass drivers and tia high drivers. Volür’s sound is engineered for “visceral bass… saturated mids [with] analog warmth… and highs [pushing] into the territory of the most resolving audio products”. No major artist roster is public for these audiophile models yet, but they are aimed at demanding listeners.

At the top, 64 Audio’s 18-driver designs are billed as studio references. The A18s (18-driver CIEM, $2999) is “the final authority on flagship in-ear monitors”[16]: it delivers crystal-clear precision along with ample “warmth, power, and headroom demanded by musicians” on the loudest stages. Indeed, many A-list artists use the A18s. Pop/rock acts like OneRepublic’s Ryan Tedder, Bruno Mars, George Strait, Beyoncé, Jay-Z, and Alicia Keys monitor on A18s, as do vocalists like Joss Stone and Adele; country, R&B, and rock performers like Lauren Daigle, Kings of Leon, and even Justin Timberlake are also on the A18s. Its universal counterpart, the U18s (18-driver UIEM, $2999), offers similarly “filtered-off” direct sound with an enveloping soundstage and no harshness, for audiophiles who need fit flexibility.

The custom A18t (18-driver “tuned” CIEM, $2999) is the ultra-high-resolution version. It “pushes the limits of what a reference monitor can be” with “incredible detail, extension, and unmatched clarity across all frequencies” and a powerful low end. This model is favored by critical studio engineers and touring acts alike. Artists using the A18t span genres: country star Maren Morris, rock veterans Bon Jovi, Latin popstar Rosalia, violinist Lindsey Stirling, soul groups like Boyz II Men, and even global pop idols BLACKPINK and BTS have adopted the A18t. (Notably, U2 splits its monitoring between the A12t and the A18t.) In sum, the A18 series represents 64 Audio’s apex: pro-grade detail for engineers and the loudest live sound.

Finally, 64 Audio offers an even more extreme audiophile model, the Fourté (4-driver UIEM, $3599). Despite only four drivers, it’s engineered as “the ultimate universal IEM for audiophiles,” with an expansive soundstage, ultra-deep lows, luscious mids, and smooth highs. It’s exceedingly pricey and rare, aimed at listeners who want top-tier performance above all else.