64 Audio U18t Universal In-Ear Monitors (2025 Edition)

Packed with an unbelievable 18 balanced armature drivers per side, U18t is our top-of-the-line reference in-ear monitor. This industry-first design sits right at the boundary of what is physically possible in a UIEM. Released and developed alongside Fourté in 2016 it is the first IEM to integrate our patented tia technology with conventional IEM design, utilizing the tia high driver and single sound bore. This astonishingly complex system results in incredible detail, extension, and unmatched clarity across all frequencies.

U18t achieves its quick bass response, while retaining enough sub-bass amplitude, by coupling eight modified mid-drivers for the low frequency band rather than using fewer/larger drivers. Another eight low-mid drivers are required to match that amplitude in the mids. The one high-mid + one tia high driver combination became the basis for 90% of our entire product range. The extremely accurate response of U18t makes it perfect for critical audiophile listeners as well as mixing and mastering engineers. Aluminum billet shells precisely milled into our signature ergonomic shape. The PVD Stainless Steel faceplates are finished with an Imperial Red enamel like chip inlay.

U18t is paired with two exclusive SPC Eight-Braid Cable, one 3.5mm single-ended and one balanced 4.4mm.

Patented Technology- tia
Tubeless In-Ear Audio (tia) is a patented IEM design methodology that aims to reduce unwanted resonance and distortion for a transparent and lifelike sound signature. The tia system is comprised of three major elements: open balanced armature tia drivers, the tia single-bore design, and tia acoustic chambers. U18t features two major elements of the tia system: the tia driver and the tia single-bore design.

Apex
Air Pressure Exchange (Apex) is a patented vent that releases air pressure in a sealed ear canal all while retaining standard IEM levels of isolation; enabling musicians and music enthusiasts to listen more comfortably for longer. This venting alleviates listener fatigue and allows for a much more realistic soundstage. Apex comes in four module variations for U18t: mX, m12, m15 and an exclusive PVD coated stainless steel m20 module.