64 Audio Duo: $1200 In-Ear Monitors Overview

This week, 64 Audio announced their Duo in-ear monitors. Just for clarification, “Duo” is the name of the headphones. It took us a couple of reads to get that so we didn’t want there to be any confusion. Your first question may be, “How fancy do these Duo in-ear monitors have to be to justify such a price tag? Let’s take a look.


Driver Type/Count2 Drivers – One dynamic driver and one balanced armature driver
Driver Configuration1 tia high, 1 dynamic low
Frequency Response20Hz – 20kHz
Sensitivity98dB/mW (98dB @ 1kHz @ 1mW (95mV)
CrossoverIntegrated 2-way passive crossover
Isolation-12dB internal apex technology

64 Audio History

To understand the $1200 price point, you need to understand a little more about 64 Audio. They are a company that provides in-ear monitors with custom-molded tips for studio and stage use (musicians and performers). They run the gamut in prices from $500 to $3000. Funnily enough, their Audiophile line starts at $1200 (with these Duos) and ends with the $3600 Fourté model. And, before you ask, the Duo means each earphone has two drivers. The Fourté? It has four. But if you want more, 64 Audio has models with up to 18 drivers in each earphone!

64 Audio Duo Design

The Duo in-ear monitors sport a lot of technology that is proprietary to 64 Audio. They have their TIA (Tubeless In-Ear Audio) driver design. It is a rectangular driver that is designed to reduce tube resonances and distortions. It is not super clear from their marketing and videos how it does this. The Tia driver handles the high frequencies while the dynamic driver handles the bass.

This is an exploded diagram of the Duo. The TIA driver is the rectangle that slips into the tube at the left. No, we aren’t going to remark on that. Why do you ask?

They also have what they call an Apex Core design. This is essentially a one-way pressure release valve within the earphone enclosure. It allows air to escape the earphone while keeping outside air out. Why would you want this? It releases internal pressure (from the backwave from the drivers) while keeping out outside noise. In other 64 Audio offerings, the Apex Core can be replaced to tune the sound isolation. The 64 Audio Duo in-ear monitors seem to be built with the -12dB valve only.

Of course, the 64 Audio Duo in-ear monitors sport dual drivers with a passive crossover. They have removable twisted-pair cables (an Audiophile staple). One of our favorite design elements is that the cable is meant to hook over your ear. These were clearly built with movement in mind. Hey, if you bought $1200 in-ear monitors, you wouldn’t want to risk losing them either!

Lastly, they come with a variety of tips so that you can find the most comfortable fit. No custom-molded tips for the Duos.

Our Take

We haven’t had a chance to listen to the 64 Audio Duo in-ear monitors yet, so we can’t comment on how they sound. The price tag suggests they should sound very good. The fact that they don’t have any of the bells and whistles of modern headphones (like in-line controls or microphones) should entice audiophiles. These are just straight headphones.

Clearly, 64 Audio throws around a lot of proprietary technology in the hopes that the “uniqueness” of their design will sell you on their headphones. This is a common tactic with audiophile companies. But 64 Audio is a legitimate company. They primarily make headphones for musicians. Their consumer offerings are called “Universal” because they have normal tips. Honestly, we’re more intrigued by their 18 driver designs. How (and more to the point why?) do you put 18 drivers into one headphone? For more information, visit 64audio.com.

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