Ultimate Ears (UE) has a storied history going back almost 30 years, which began with the creation of the custom-fitted musician’s in-ear monitor (IEM) category in collaboration with legendary rock drummer Alex Van Halen. More recently, after its acquisition by Logitech in 2008, UE entered the broader audio consumer consciousness with its well-received line of powerful portable Bluetooth party speakers, such as the UE HYPERBOOM.

UE still caters to the needs of professional and semi-pro musicians needing IEM solutions for the stage and studio through its UE Pro division, with a range of products, including the UE 5 Pro and the UE 18+ PRO. The UE Pro PREMIER is the company’s top-of-the-line custom-molded IEM boasting a crazy 21 balanced armature drivers in each earpiece, costing $2999 at Manufacturer site a set. Let’s dig in to see what kind of experience and sound quality that gets you.

Editor’s note: this is the first version of the article. Updates will follow as the market changes.

The user experience with the UE Pro PREMIER begins with a visit to the UE Pro product page. Here, you’ll make color selections and decide whether you want to add a cosmetic “Halo,” UE Switch swappable faceplates, cable length, and color choices. You can also add an ambient feature that adjusts how much environmental sound you want to hear (for a $50 up-charge). For our review sample, I selected “Royal Blue” translucent for the left and “Lucky Red” translucent for the right, with no “Halo” or ambient feature.

Then there’s the minor detail of going to an audiologist and getting your ear impressions made — UE Pro provides a handy page of instructions and requirements to take with you. Then, you mail the physical impressions to Southern California, which are digitally scanned and kept on file. At the time of ordering, there was a 25-business-day lead time for the product, which includes quality control checks of the custom-crafted earphones.

When my package arrived, taking the freshly made custom IEMs out of the basic black cardboard packaging and sliding them into my ears was quite a treat: the unusual experience of having something fit deep into my ears so effortlessly. The IEMs feel pretty large in hand but are relatively lightweight at less than 9g a piece, and once they are nestled in your ears with a simple push, you quickly forget about them. They are supremely comfortable— critical for something intended to be worn for many hours. It’s worth noting that while the housing material feels just like hard plastic (there’s no foam or rubber between it and your ear), it seals well, as evidenced by the immediate sensation of isolation from my surroundings. They feel secure but are quick and easy to take out and put in again repeatedly.

The SuperBAX cable attaches to each IEM with a tiny removable coaxial connector on the forward-facing edge. At this end of the cable, there’s an approximately 100mm long external cable sleeve (matched to the cable color) that gives the cable some rigidity where it loops over and behind your outer ear, keeping the cable out of the way, guiding it toward the back of your neck. There, it can be cinched in place with the sliding Y-split joint that gives you control of where the left-right cable split occurs, securing the cable quite effectively at the back (or front) of your neck, making unintended pulls on the cable less traumatic on your ears.

I find that this cable is very prone to getting tangled with itself, and whenever I remove the IEMs and store them, they tend to end up in a knot. If UE included a cable management solution to prevent this, it would save a lot of time.

To assist sound guys on the road with bands using multiple sets of the UE Pro PREMIER, each one is individually engraved with initials to identify the owner. The 85 x 75 x 45 mm Ultimate Ears square case can also be engraved with your name for no extra charge, which is a nice touch. It also has a cleaning tool attached to the inside of the lid, another thoughtful detail. While sturdy, I found the case to be unwieldy and annoying to open with its gasket-fitted, fully detachable (rather than hinged) lid. I end up repurposing a soft zippered case from a far less expensive set of earbuds for stowing the UE Pro PREMIER and carrying it around during the review period.

Our sample came fitted with the requested 1.27m (50″) long IPX Earloop Clear Cable, terminated in a standard, non-threaded right-angled 3.5mm gold plated TRS jack plug. No adaptor for 1/4″ outputs is included. You can opt for a longer 1.63m (64″) cable; both lengths are available in black or clear. If you’re looking to use these with a balanced (differential) output, you’ll need to add the 50″ Balanced IPX Cable With Earloop to your shopping basket ($149).

The connector used to attach the cable to the IEMs isn’t a standard two-pin connector or the MMCX connector most people associate with this product category. Instead, they use a smaller coaxial connector called the IPX Connection System. According to UE Pro, MMCX was deemed to have poor reliability, so consequently, this new system was designed from the ground up. This cable and connector system is built specifically to withstand the rigors of touring musicians, minimizing the need for service and maintenance, and has been tested for over 3,000 connection cycles.

How well do the UE Pro PREMIER block out noise?

Passive noise isolation is one the most significant benefits of getting a good fit with your headphones, and an individually custom molded earpiece should get you close to the theoretical ideal in that regard. Our measurements show that these do indeed offer some of the best passive acoustic isolation we’ve seen, in line with the musician’s hearing protection earplugs we’ve tested in our lab.

In the low-frequency region below 1kHz, attenuation of external noise averages around 15dB, and above that rises to over 45dB around 3kHz. This means you’ll still have an impressive signal-to-noise ratio even when monitoring at low levels. This provides excellent isolation from your surroundings, whether that’s a concert stage with live drums and roaring amplifier stacks or the sound of the subway on your ride home from work.

How does the UE Pro PREMIER sound?

Before we dive into the actual sound, it would be remiss of me not to first break down the impressively complex acoustic integration these IEMs boast internally. It’s a highly unusual multiway design employing a five-way passive crossover to divide up the incoming signal between drivers that perform optimally with specific frequency ranges. Avoiding any comparisons with the blade count arms race in the shaving industry, both the left and right in-ear monitors are loaded with the following components, which are all based on balanced armature (BA) technology:

• one True Tone Plus proprietary driver (delivers upper-register harmonics and overtones)
• one quad-high super tweeter
• one quad-mid driver
• four dual diaphragm mid-low drivers
• two dual sub-low drivers

There’s clearly a lot going on here, making me genuinely curious about what this added complexity could bring to the table, sonically speaking. With the IEMs placed firmly in my ears, my first listening test involved plugging the jack into my iPhone via an Apple DAC dongle. I cued up my test track playlist, closed my eyes, and pressed play.

Editor’s note: this review uses a hover-enabled glossary to describe sound quality based on a consensus vocabulary. You can read about it here.

If you’re in the market for custom-molded in-ear monitors, you might be drawn towards the UE Pro PREMIER. With its large driver count and high price, you might conclude that this is the best available product in this relatively niche category. However, based on my experience with them, I don’t consider that the case, due primarily to the odd tuning decisions made at UE that don’t benefit the listening experience or deliver the full capabilities of the hardware within.

Out of the box, the UE Pro PREMIER has notable sonic deficiencies, as outlined in the section above. However, if your source device has decent onboard equalization available (whether it’s analog or DSP), and you’re willing to spend some time fine-tuning the output to compensate, then you’ll be rewarded with excellent sound reproduction across the spectrum.

If you’d rather get something that has a better-optimized frequency response out of the box and doesn’t require significant tweaks, plenty of (non-custom) IEMs can do the job. It’s also worth noting that even though it was instrumental in developing the custom-molded IEM concept, UE isn’t the only game in town if you want to go the custom route.

Whether you’re looking for monitors for stage or studio use or casual listening, my first recommendation in this product category is the Shure SE215. This industry standard retails for $99 at Amazon. You can purchase them off-the-shelf with a good selection of ear tips, providing fantastic isolation making them a mainstay in pro-audio circles.

If you want a better-tuned frequency response for critical music listening, then either the Sennheiser IE 900 for $1199 at Amazon or their more affordable sibling, the IE 600 for $599 at Amazon are great options. These both aptly demonstrate that sometimes simpler is better, as both use a single full-range driver to achieve better results than the UE Pro PREMIER does with its 21 drivers.

When it comes to custom-fit alternatives to the UE Pro PREMIER, UE Pro has other options but isn’t the only game in town. One inexpensive example that’s recently come to our attention is the ADV Model 3 Custom, an affordable IEM product that works well and can be converted into musician’s earplugs quickly and easily, making it an incredibly flexible and cost-effective option.