64 Audio A4s Custom In-Ear Monitor adapter and the overall sound is

and the overall sound is smoother and more durable

Forming the basis of the Ultrasone Performance 840

which brings high-efficiency

DSD Support

Maximum Output (SPL): 122 dB

64 Audio A4s Custom In-Ear Monitor adapter and the overall sound isA4s 64 Audio is proud to introduce our newest four driver custom in ear monitor, A4s. This complete redesign of our four driver platform is elevated by the Dynamic low frequency driver, making this 64 Audios second hybrid custom IEM. Along with that major update, inside A4s is our Tia technology, LID and our patented Apex and 3Dfit tech. While this is targeted at musicians looking for a rich enveloping monitoring experience, the frequency response,