Up to now, Oppo hasn't been a brand that is usually associated with personal and two-channel audio. Oppo made its name in video with market-leading DVD players and then universal disc players. However, just as man cannot live by bread alone, Oppo has widened its manufacturing horizons with two new audio products: the PM-1 planar headphones and the HA-1 DAC/headphone amplifier.
This review will focus on the PM-1 headphones. With a street/list price of $1,099, the PM-1s are aimed directly at the center of the high-performance, premium-priced headphone market. Just as Oppo's entry into the DVD and universal player market created quite a stir, the company's new headphones could cause an equal amount of upheaval among headphone manufacturers. But are the PM-1s a game-changer or merely another competitive high-quality headphone option? Let's find out.
The PM-1's design is based around its own proprietary planar magnetic driver. This driver has a large 85mm-by-69mm, seven-layer diaphragm that uses a spiraling pattern of flat conductors on both sides of the diaphragm. This scheme increases the headphones' sensitivity and gives them a higher damping factor. The PM-1 has a sensitivity of 102 dB per one mw and a nominal impedance of 32 ohms, so the power amplifier in any smartphone, tablet, or portable music device should drive these headphones easily. This differentiates the PM-1 from other planar headphone designs. The 32-ohm PM-1 was created to be unfussy (as far as amplifiers go) so that it can perform optimally with a wide variety of devices. I used them with a variety of portable devices, including the Astell & Kern AK100 and AK240, Calyx M player, Colorfly C4, iPod classic, iPod Touch, and my iPhone 5. In every case, the mating supplied the PM-1s with more than enough juice to play as loudly as I could stand with ample room to spare, gain-wise.
The over-ear PM-1 has an open-back design created for optimum sound quality and comfort. Most closed-back headphone enclosures add both weight and inevitable "cabinet resonances" that reduce their comfort and fidelity, but open-back designs have their own set of chronic issues. They do very little to reduce the amount of sound that leaks from your headphones into the outside world, and they do not deliver much in the way of isolation. If your primary purpose for using headphones is for seclusion from outside noise and for privacy, a closed-back headphone or in-ear monitor would be a better choice. Given how the PM-1 headphones can fold up into such a compact package inside their travel case, it's unfortunate for audiophiles who need to travel light that, given the PM-1's open-air design, they can't serve as a universal headphone solution. But augmented by a pair of high-isolation in-ear monitor-types, such as the Etymotic ER-4 or custom in-ear monitors like the Westone ES-5, the PM-1 headphones could still serve a road warrior well, especially in a quiet hotel room at night.
Although they weigh only 0.85 pounds, the PM-1s are solidly built with machined metal parts and lambskin leather coverings. The attention to detail extends to the tinniest details, such as the shiny beveled edges on the satin-finished ear yokes, which even includes a tiny edge around the headphone cable. The PM-1's overall fit and finish rival any luxury product I've seen, including automobiles and designer handbags. The inclusion of two very different and easily interchangeable cables is something that every manufacturer that makes headphones with removable cables should adopt. For travel, connected to portable devices, the shorter, lighter cable works great. At home, the longer, cloth-covered cable has the extra reach to allow for freedom of movement, at least for most folks, most of the time.
This is a good time to mention one of the PM-1's greatest strengths: comfort. They are tied in my personal pantheon of comfort with the Sennheiser HD-600 headphones. On my 7.13-hat-size head, the PM-1s are much more comfortable, especially after more than an hour of listening time, than the Audeze LCD-2 Bamboo or the AKG K-701 headphones. During the two months that I've been using the PM-1s, I have had ample opportunity to "torture test" their cable connections. The PM-1s are so comfortable that, at least 10 times (I stopped counting after a while), I got up from my desk and began to walk away, having completely forgotten that I still had the headphones on, since they weren't actively playing music. The results were predictable yet startling - after a couple of paces, the cable was yanked out, usually at the earpieces. Every time, except for the initial shock, there was no harm, no foul. The PM-1s survived multiple unintentional traumatic disconnections with no damage whatsoever to headphones or cables. That is rugged.
While on the subject of ruggedness, I would be remiss not to comment on the overall build quality, especially at the critical stress areas. According to Oppo's product literature: "Quality control includes cross measurements for various forms of distortion and even clamping pressure. During the EVT (engineering verification test) a sample headband is stretched and its ear cups are rotated 20,000 times by machine to insure structural integrity, then twisted 5,000 times to check for environmental stresses. " Since the parts that can wear out (such as earpads and cables) are easily replaceable, for most users the PM-1s should, as long as they're not abused (such as being worn during a sandstorm), last longer than their original owners.
Another thing that will probably last longer than its owners is the PM-1's packaging. The outer cloth-covered slip case, humidor-quality lacquered presentation box, two cables, two sets of earpads, and cloth portable carrying case increase the shipping weight of the 0.85-pound earphones to over 10 pounds total. That's a whole lot of shipping costs for that big ol' deluxe package. More frugal types will be interested to learn that Oppo plans to introduce a companion model, the PM-2, for $699 without the deluxe packaging and with some of the metal parts replaced by less-expensive-to-machine plastic. Oppo claims the two headphones will sound virtually identical. Hopefully the PM-2 will be as rugged as the PM-1.
Click on over to Page 2 for the Performance, High Points, Low Points, Competition and Comparison and the Conclusion . . .