Comparisons
In the comparisons section I want to quickly compare the U4s to two other models. One of which is a stable mate from 64 Audio and the other is an IEM by Empire Ears that has developed sort of a cult following when it was launched.
vs Empire Ears Phantom
The Phantom is a five driver BA-only monitor that has a very thick and syrupy sound to it. For a balanced armature IEM the bass is very satisfying and very well layered. But in comparison to the U4s it can’t hold a candle. The lows of the U4s are faster, more energetic and dynamic. It sounds more organic and realistic.
The Phantom has a darker and thicker midrange, where all instruments and vocals sound even heavier than on the U4s. The U4s has a more open mids-section, even with the M15 or M20 installed. Change the module to the M12 or MX and the U4s will leave the Phantom in its rear-view mirror for good.
In terms of resolution and sound stage the U4s also has the upper hand compared to the Phantom. The U4s creates a slightly wider and taller stage compared to the Phantom. It also separates instruments and musicians in a sharper manner. It has a blacker background and better imaging.
The treble of the U4s is brighter, sharper and more extended than on the Phantom, which can sound a bit muffled and muted.
Overall the U4s sounds more open and more dynamic than the Phantom.
vs 64 Audio Duo
64 Audio’s Duo is one of their three tube-less models. As the name spoils it uses two drivers (1BA+1DD).
The Duo is 64 Audio’s only semi-open IEM, this makes the Duo almost unusable outdoors as the sound leaking in is impossible to keep out. The U4s is far better suited for that. Of course there is a similarity in sound between the two, given they are both from the same company.
The U4s and the Duo both have a smooth and warmer sound in its signature, although I find the Duo to be more vivid and open sounding than the U4s (M15). The U4s on the other hand has a more punchy low end that delivers more energy. The Duo has an even smoother sound. Its lows don’t stand out as forward as the U4s’. Although you can always change the U4s’ sound by simply installing a different module.
The U4s has a sharper edged and brighter treble tuning. The Duo on the other hand has superior resolution, staging and imaging. The Duo is one of the (if not the) best performers in this price category when it comes to technicalities, and the U4s won’t change that.
Final Verdict
I have to admit, whenever I hear about a new release from 64 Audio they have my full attention. The A18s and Fourté Noir are still among my absolute favorite IEMs. I am always glad to see 64 Audio push their technology into more affordable products. Though 1,099 USD is still a lot of money, the U4s is their cheapest universal IEM to date.
Personally I would love to see even more affordable options coming out from 64 Audio in the future, only because I think they should make their excellent sound available to a broader audience.
Over the course of the last months I have played around with the U4s a lot. I have found myself reaching for it many times even when I had other higher end IEMs within my reach. The U4s’ energetic sound can absolutely grab you and keep you attracted.
The U4s has become one of my daily drivers, especially when I’m at the office. It has also gotten to be my prime work-out and sports IEM. The bass of it keeps me on my toes and motivated to my fingertips.
The fact that the U4s basically comes with four different signatures is an extremely big plus in my books. You want a more open sound with wider image? Go for the MX or M12. Need more bass? The M15 or M20 should be your choice. I love the versatility of 64 Audio’s universals and the options they give their customers with the Apex modules. To me it is an easy recommendation!
Pros:
– Versatile sound with four Apx modules
– High quality sound for mid-fi pricing
– Extremely good build quality
– CIEM option
– Great set of accessories
Cons:
– Lack of termination options (4.4mm would’ve bee nice)
Page 1: 64 Audio, U4s
Page 2: Package, Build Quality, Sound
Page 3: Comparisons, Verdict
