Ultimate Ears' new Reference Monitor in-ear headphone is a very different take on the state of the art. UE collaborated with EMI Music's Capitol Studios to design this headphone for recording, mixing, and mastering engineers. The UE engineers submitted a number of prototypes to Capitol and other beta testers for feedback before arriving at the finished Reference Monitor. I'm no engineer, but I think the Reference Monitor is the best, most accurate-sounding in-ear headphone I've heard to date.
Right, I know some of you must be thinking, aren't all headphones designed to be accurate? Once you listened to a number of headphones you'd know that's far from true; they all sound very different. They can't all be right.
I spent a lot of time comparing the Reference Monitor ($999) with Ultimate Ears previous and still available flagship headphone, the UE 18 Pro ($1,350). The UE 18 Pro is still very impressive, but it has a prominent bass bulge the Reference Monitor lacks. The new design is more accurate, with a flatter frequency response, so the Reference Monitors have a more audiophile oriented sound perspective.
That said, I prefer the UE-18 Pro's extra bass when I listen in noisy environments, like the NYC subway. There, the Reference Monitors sounded a little bass-shy because there was a lot of low-frequency background noise masking the music's bass. The UE-18 Pro's bass bulge compensates for that to some degree, so if you use headphones in noisy environments or prefer a fuller tonal balance, get the UE 18 Pro. In quieter places the Reference Monitor's bass will be more accurate, and its bass goes even deeper than the UE-18 Pro's.
Philippe Depallens, Ultimate Ears' VP & General Manager filled me in on the details about how the Reference Monitors differ from the company's other custom in-ear models. The Reference Monitor sports three individually tuned, balanced armature drivers (bass, midrange, treble) in each earpiece; the UE-18 Pro has six individually tuned, balanced armature drivers (double bass, midrange, treble) in each earpiece.
Depallens also told me the Reference Monitors are available in two slightly different versions for the same price, one with a standard acrylic "shell" (or body) that provides up to 26 dB of sound isolation, or the Reference Monitor can be ordered with a soft silicone material over the acrylic shell that provides up to 32 dB of noise isolation. I had the standard version, which blocks outside noise at least as well as most battery-powered noise-canceling headphones. External low-frequency noise/rumble from buses, trains and jet engines are as much felt as heard, so the noise isolation (or noise canceling) can't block that kind of noise.
Tal Herzberg, the Grammy-winning recording engineer and producer who has worked with the Black Eyed Peas, Pussycat Dolls, and Mary J. Blige, uses Reference Monitors. He described the Reference Monitor this way: "What is unique is that I find myself not worrying about environmental noise. Once I put these on, the isolation is so good, room noise is virtually eliminated. All I hear is the natural, dimensional sound the monitors create, allowing me to accurately record and mix."
I started my auditions with the "French Dub Collection" CD, which amply demonstrated the Reference Monitors' bass dexterity and ultradeep bass extension. The UE 18 Pro sounds like it has much more bass than the Reference Monitor on most recordings. The difference is the UE 18 Pro has more midbass, (I'm guessing around 70 to 100 Hz bass), but the Reference Monitor has flatter overall bass, and superior low, 30 to 50 Hz bass oomph. To my ears, the Reference Monitor's bass definition is well ahead of that of the UE 18 Pro, and all other custom in-ear models I've heard. That said, the bass still doesn't have the weight and impact of full-size, over-the-ear headphones.
Westone's ES5 ($950) is another contender for world's best custom in-ear headphone, but for now I'll say it doesn't appear to be as ruler-flat accurate as the Reference Monitor. Look for my ES5 review soon.
The Reference Monitor sounded best when played at home with dedicated headphone amps, like my Schiit Asgard. There, the Reference Monitor sounded significantly more powerful and shockingly dynamic with the amps than they did with my iPod Classic or Hifiman HM-602 music player (the HM-602 was better than the iPod). Not that the iPod Classic sounded bad, not by a long shot, just that with a headphone as good as the Reference Monitor, you really can hear the difference between amps.
The Reference Monitor's resolution of detail is extraordinary. When I played Paul McCartney's "Unplugged" CD I heard things I never heard before, like one of the other musicians very quietly singing "yeah, yeah" in the background on "Ain't No Sunshine." There's a vivid, you-are-there quality to the sound that totally knocked me out, and I've never heard another in-ear headphone that can touch the Reference Monitor in that regard.
Since each custom in-ear monitor is handmade to fit your ear, you need to schedule an appointment with an audiologist who can make "impressions" of your ear canals. The molds are sent to UE, where they are used to make your headphones. Ultimate Ears can build Reference Monitors in any color you want, and apply custom artwork to the outer shells. The standard art work features the Capitol Studios logo on the right monitor and the Ultimate Ears logo on the left monitor. UE's base custom model, the UE 4 Pro, goes for $399 (review to come). UE also offers a broad range of "universal" (not custom) in-ear headphones with prices starting at $20 for the UE-100.
The Reference Monitor comes with a one-year warranty, but if you don't beat them up, the headphones should easily last 10 years. Sure, if you're rough on cables and break 'em on a regular basis, that's a good reason to consider a UE custom 'phone. Replacement plug-in 48-inch-long cables go for $40; they do seem extremely well made and should be very durable over the long run. UE also sells 64-inch cables for $45.
So sure, the Reference Monitor is expensive, but the good stuff always is. If you love music and can afford the Reference Monitors, they're worth it. One way to justify the expense is to think about how many years you'll potentially get out of a set of Reference Monitors, which will certainly sound a lot better than the next ten $100 headphones you'd buy over the next 10 years.