64 Audio A4s 4 Driver Custom In Ear Monitor

Build Time:
6 Weeks
Key Features:
  • 4 driver hybrid design
  • Rich, natural bass timbre
  • Apex pressure relief system
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64 Audio is proud to introduce their four driver custom in-ear monitor, the A4s. This complete redesign of 64 Audio's four driver platform is elevated by the Dynamic low frequency driver, making this 64 Audio’s second hybrid custom IEM. Along with that major update, inside A4s is 64 Audio's Tia technology, LID and patented Apex and 3Dfit tech. While this is targeted at musicians looking for a rich enveloping monitoring experience, the frequency response, detail, and soundstage capabilities of A4s exceed other audiophile products at almost any price point.


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What's in the box

  • A4s Custom In-Ear Monitors
  • 64 Audio Personalized Protective Case
  • Dehumidifier
  • Cleaning Tool
  • Shirt Clip
  • 48" or 64" Detachable Professional Cable
  • m20 apex Modules
  • Round Sticker
  • Product Manual


Transducer Type Dynamic & Balanced Armature
Transducer Configuration 1 dynamic low, 1 BA low-mid, 1 BA high-mid, 1 tia high
Bore Configuration Single
Frequency Response 10Hz – 20kHz
Sensitivity 107 dB/mW (94mV) @ 1kHz
Impedance 11Ω @ 1kHz
Crossover Integrated 4-way passive crossover
Isolation 20dB w/ m20 module, -15dB w/ m15 module. Ships with M20 Module stan

Audio Performance

Drivers4 Drivers
Sound Signature
Deep bass and forward highs


Low Mid

Mid High


Resolution (7)

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With nearly two decades experience as a sound engineer, Vitaliy Belonozhko founded 64 Audio when he discovered the advantages of IEMs over traditional floor wedges. With unique technologies such as the Tia tubeless driver design and the Apex pressure relief system, 64 Audio consistently aims for high performance, balanced sound with practical, ergonomic fit.

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