OPPO PM-1 Headphones

Since I’m not much of a headphone guy, it takes something special for me to leave the comfort of my listening room and put a pair of cans on my head. Few ‘phones have ever given me big enough goosebumps to do so, and those that did have all been planar or electrostatic. No surprise, since most of my favorite speakers are panels. There’s just something about the open, airy presentation you get from a great pair of ESL speakers. OPPO’s new PM-1 planar magnetic headphones take me to that desired place.

By nature, headphones provide the same feeling of sound pressure offered by a pair of large speakers in a room. Still, the PM-1s deliver a degree of fine sonic distinction often mustered by six-figure speakers. If you’re a music lover considering plunging into audiophilia, a pair of PM-1s are your stairway to heaven.  And while you’re at it, grab OPPO’s matching HA-1 headphone amplifier/DAC. (Full review is in the works, but it’s equally enticing.)

Recent entries from HiFi Man and Audeze redefined the paradigm for what constitutes a great headphone obtainable without spending the megabucks required for top-of-the-line Stax headphones. Now, another name can be added to that elite group— OPPO, the folks that make one of the world’s best combination disc players at an incredibly reasonable price.

Sure, building world-class headphones requires a completely different skill set than manufacturing disc players, amplifiers, and DACs. But OPPO’s design ethos binds these products together. No detail is left unaddressed, and in typical OPPO fashion, the packaging is exquisitely refined without being ostentatious. The PM-1s offer performance concurrent with the worlds best ‘phones, yet are priced at a very reasonable $1,099.

That Good

Listening to Robin Trowers’ highly phased lead guitar on his For Earth Below album instantly reveals the delicacy the PM-1s can capably deliver. They play loud and clean, and throw a prodigious stereo image, making me feel like one of those guys on the fruit roll-up commercial whose head explodes when a grape-flavored candy gets ingested.

The PM-1s are so clean, dynamic, and undistorted, you will have to be careful with the volume control so you don’t hurt yourself.  If you pair these with a premium headphone amplifier capable of a lot of juice, you’ll be tempted to crank the PM-1s beyond the point of pain. I noticed a slight buzz in my ears after playing U2’s Rattle and Hum at a rather enthusiastic level, so don’t say I didn’t warn you.

However, playing loud isn’t necessarily as easy as playing soft. Squeeze’s classic Spot the Difference is full of stylistic departures from the original versions of the band’s top tunes. When listening closely via the PM-1s, it becomes much easier to hear differences in the mix. Glenn Tilbrook’s lead vocal on “Is That Love” is more stripped down, yet also throatier, with drums, rhythm guitar, and bass better separated as the piano sneaks in and out. Experience the same track on a budget pair of ‘phones, and the intricately woven ball of sound collapses into a flat, one-dimensional sketch. Even densely packed recordings, like the self-titled Audioslave album, reveal additional nuances (guitar fills, vocal layers) through the PM-1s.

Bottom, Top, and Middle

As it is in speakers, coherence is key to planar sound in headphones. There’s a natural ease to the sound of the PM-1s that I’ve never experienced with a pair of dynamic ‘phones. Call it a lack of grain (especially with acoustic instruments) that helps the listener forget they’re wearing headphones in the first place.

The upper register revealed by the PM-1s is smooth albeit extended. The gentle mix of drumming, keyboards, and Miles Davis’ horn on his classic Bitches Brew comes together in an alluringly homogenous manner to the extent the sound feels like it’s coming directly from your brain stem, deep inside your head, with a touch of tape hiss from the master tape floating out beyond your consciousness—but there to keep you aware you are listening to an analog recording.

Davis’ double-album effort is an equally good test for bass, as many tracks feature acoustic and electric bass guitars comprising the rhythm section. Most ‘phones reduce this information to a single bass line. The PM-1s have enough resolution to pluck both instruments from the mix and appropriately present them.

A wide range of acoustic test tracks underlines the PM-1s’ ability to nail musical fundamentals. Instruments sound stunningly correct from a tonal perspective, no doubt in part to the incredibly low distortion of the driver, which uses a double-sided design and more conductors than other planar magnetic models. OPPO claims that, in addition to additional sensitivity, it offers tighter damping, contributing even further to the natural response.

Efficiency is Key

The PM-1s’ additional sensitivity and nominal 32-ohm impedance make them a breeze to drive with your mobile device. While these headphones definitely benefit from a premium headphone amplifier, your high-end audio journey can start with an iPod. Tracks saved in Apple Lossless via the iPod Mini render headphone amplifiers unnecessary on an extended business trip.

In addition to electrical efficiency, the PM-1s are considerably lighter than competing planar ‘phones (395 grams vs. about 600 for my reference Audeze), making them easier for the un-headphone guy (and perhaps you) to enjoy more extended listening sessions.

Combining high electrical efficiency with benign impedance also means the PM-1s are simple to drive with any headphone amplifier. OPPO’s HA-1 might be the obvious choice, but we experienced great results with a number of different solid-state and vacuum-tube headphone amplifiers. Moving up the ladder to the new Cypher Labs Prautes ($3,695) and ALO Studio Six with Teflon capacitors ($4,995) proved breathtaking, and removed yet another barrier to sonic reality.

Nary a Misstep

Considerable time with the OPPO PM-1s reveals no shortcomings. While the hardcore headphone enthusiast will no doubt want to add the PM-1 to their stable, more monogamous headphone lovers will find simple sonic bliss. I know I did.

The PM-1s combine everything we find of high virtue at TONEAudio: high performance, aesthetic purity, and careful attention to detail. All at a reasonable price. This is the new benchmark for premium headphones.  – Jeff Dorgay