What 64 Audio says:
The pinnacle of in-ear monitor technology, Fourté takes full advantage of everything we’ve learned up to this point in designing world-class in-ear monitors. Fourté boasts the most accurate sound and widest soundstage of any in-ear monitor, making it the perfect choice for audiophiles seeking detailed, lifelike audio, and three-dimensional sound.
Fourté features our complete, three-part tia™ system housed in an ergonomic shell, machined from a solid piece of aluminum and finished with elegant, copper patina faceplates.
3 precision BA drivers, 1 dynamic driver
1 tia high, 1 high-mid, 1 tia mid, 1 dynamic low
5Hz – 22KHz
114db @1kHZ @1mw
10 Ω @ 1kHz
Integrated 4-way passive crossover
-20dB internal apex technology