Over the past few years, 64 Audio (formerly 1964 Ears) has come on strong as a provider with a full line of IEM earpieces for musicians and audio professionals alike. The A Series offers a choice of eight designs from $599 to $1,999 made from your custom earmolds. The U Series (Universal fit) has models starting at $399 (for the dual-driver U2) and ranges up to the U12, which are $1,599.
All 64 audio earpieces also feature ADEL technology, which places a passive secondary membrane — functioning almost in the same way as a passive radiator would in a sealed speaker enclosure — while offering a variety of acoustical and auditory benefits, but more on that later. I was intrigued and wanted to check out a set of U12’s first-hand.
All models ship with fixed (they refer to these are “Auto”) ADEL modules. One option is variable (referred as “Manual”) ADEL modules, which easily interchange to make acoustical tweaks, to suit your preferences.
Other option possibilities on the A Series are extensive, including faceplate (colors, materials including wood, shell colors, custom artwork/logos and more), and a choice of black or silver cord colors in either 48- or 64-inch lengths. Speaking of the cable, these are interchangeable and terminate in a standard 90-degree 1/8-inch stereo TRS plug. The cables themselves have the conductors in a twisted (rather than smooth-jacketed) configuration, and I felt this made them less prone to tangling.
Inside the U12’s
Underneath the hypoallergenic, hard acrylic shells of these top-of the line U12’s (or A12’s) is a precision transducer with 12 balanced armature drivers — four LF, four MF and four HF — in a quad bore design with an integrated 3-way crossover.
Also standard is a tough molded case that stores and protects the earpieces while in transit. They also come with extras including a cleaning tool, shirt clip to keep the cable in place while performing, insets to house four ADEL modules and a mount that keeps the cable from tangling while in the case. One nice touch is an included dehumidifier module that snaps into place inside the case and wicks away any atmospheric moisture to keep the earphones dry.
Being a universal fit design, all U Series earpieces (including the U12’s) come with eight ear tips — two of each in four sizes/styles — that fit onto the specially angled spout. From the first try-on, I found that these offered a good combination of a comfortable fit and an effective seal from external noise sources. Obviously anyone seeking more complete isolation would consider the custom A Series line.
The U12’s are a 16-ohm design, and I experienced no weirdness on that end using them with a variety of systems, ranging from IEM modules to console headphone amps to outboard headphone amplifiers.
What I did experience, however, was that the U12 earpieces are extremely easy to become accustomed to — in fact, there was no adjustment period here, it was simply plug-and-go in the most literal sense. While some IEM earpieces are designed with an extra low-end bump or a midrange presence boost, not so here. The net effect of listening on the U12’s was naturalness with a full audio spectrum — from the lowest bass notes to the extended high-end response. And I could not detect any crossover artifacts or edginess between driver regions. The imaging was spot-on, with a wide and spacious left-right soundfield that was quite detailed and really pinpointed panning changes.
Bring on the Manual ADEL Modules
So far, so good, but up to this point I was using the Auto ADEL modules and was interested in checking out the variable acoustics versions. The modules themselves are quite small and fit snugly into their sockets on the rear of each earpiece. Once I removed the first one, I found out why. These are constructed with a precision-machined aluminum outer case with two tiny O-rings that provide a tight seal. One thing I would avoid is changing these anywhere where they may be hard to recover if dropped, as they are quite small. But popping in the replacement set of Manual ADELs was straightforward. Over the next couple months, 64 Audio will offer these as retrofit options for its existing owners, and they will also be offered as a factory option for new orders.
A small knob on the rear of each Manual ADEL unit can be rotated for a full seal (like a traditional IEM) or a turn of the knob inward begins closing the acoustical ports and offering increased amounts of ambience.
The effect of the Manual ADEL tweaks is not sledgehammer at all, and is fairly subtle, while at the same time noticeable. But within that range from sealed to fully opened, you can match your eardrum’s impedance and you can fine tune for your sound preference (or your environment) for your ideal listening setting. On a really noisy stage — or simply listing while on an airplane, for example — you might want to have them sealed off for maximum isolation, but for slightly quieter environments, you might want to have them more open — with the net effect like an open-back headphone, providing a wider, more spacious effect.
A more longer-term effect is that the tympanic motion of the tiny ADEL membrane moves in concert with the sound bouncing off the eardrum — much in the same way that a tuned membrane bass trap in the rear of a hall can absorb back wall slap. This results in reduced ear fatigue — these definitely have little fatigue, even after long-term listening — but also, according to 64 Audio, this pistonic action of the ADEL membrane can also reduce the chance of hearing loss from prolonged earphone use.
The End Game
As for me, I like these. The earpieces have a rich, full fidelity sound that’s balanced with a wide frequency range and fast transient response. The ADEL technology (used with either Auto or Manual modules) is effective and a nice plus to some great sounding IEM’s. I like that.
At a Glance
High-Performance Earpiece
The flagship of 64 Audio’s line of IEM’s, the universal fit U12 (and custom A12) models combine a high-end 12 armature transducer with ADEL technology that offers benefits beyond the “usual” earpieces.
64 Audio U12/A12
PROS:
• Natural sound
• Solid construction
• Versatile ADEL technology
CONS:
• Somewhat pricey
• Universal-fit U12 models cannot convert to custom earmolds
STATS
- Configuration: 3-way design with 12 balanced armatures
- Impedance: 16 ohms
- Price: U12, from $1,599; A12, from $1,999
- Manufacturer: 64 Audio
- More Info: www.64audio.com
About ADEL
The ADEL technology was developed by inventor Stephen Ambrose (now founder and chief scientist of Asius Technologies), who in 1978 designed and built the first in-ear monitoring system, created as custom products for Stevie Wonder and other artists.
Known as the patented Ambrose Diaphonic Ear Lens (ADEL) technology, the ADEL module contains a membrane — essentially acting like a secondary ear drum that’s more compliant than a natural ear drum. When an earpiece is sealed within an ear canal, its speaker’s pneumatic air pressure can cause the eardrum to move excessively ADEL is designed to absorb pneumatic pressure in the ear canal for a safer listening experience, while reducing ear fatigue and offering a more natural sound.
