MrSpeakers Alpha Dog headphones ($599) are the world's first 3D printed production headphones and as such certainly deserve a place in the Guinness Book of World Records. But unlike a counting horse or a talking cat, the MrSpeakers Alpha Dog has additional redeeming social value: it attempts to deliver a closed-cup, isolating headphone that sounds as open and sonically unencumbered as an open-air headphone. In the past, many headphone manufacturers have tried to achieve this sonic goal, and few have succeeded. Perhaps the addition of 3D printing technology can bring this ideal to full fruition. Let's find out.
The Alpha Dog headphones are an around-the-ear closed-cup design that utilizes a complete seal around the ears to deliver maximum physical isolation. The Alpha Dog's basic driver components are the same as those of the Fostex T50RP headphone, but the driver is completely rebuilt with modifications by MrSpeakers. The stock Fostex RP driver employs a diaphragm material made of foil-etched polyimide film that is formed in a special zigzag pattern. This zigzag foil pattern reduces frequency peaks, especially in upper ranges, when compared with similar drivers using a straight patterned foil. The Fostex RP driver also employs neodymium magnets that deliver three times the flux density of conventional magnet designs. The original driver's specifications claim a frequency response of 15 Hz to 35 kHz with a maximum input of 3000 mW and 50-ohm impedance.
The Alpha Dog also uses a Fostex headband and cup attachment arms, but the cups themselves, the cables, the connecting hardware, and the earpads are all unique MrSpeakers designs. When compared with a Fostex T50RP headphone, it's easy to see why the Alpha Dog costs five times more - its overall fit and finish is much higher in materials and construction quality than the T50RP. The Alpha Dog's ear cups have a rich, dark, metallic burgundy finish, while the headband, ear cushions, and most of the hardware are professional black.
Another unique feature in the Alpha Dog headphones design is its Very-Bass bass adjustment screw, which alters the inner volume of the Alpha Dog's enclosure and in turn changes the overall bass output level of the Alpha Dog. Although this setting is user-adjustable, MrSpeakers does not recommend that end users arbitrarily fiddle with the factory settings. The screw is first and foremost a production-line adjustment that makes it possible for MrSpeakers to dial in the harmonic balance to spec. Of course, nothing is stopping an end user from changing the settings but, if they get too far out of whack, the headphones could require a return to MrSpeakers for recalibration, which can be done for a "tuning fee" of $29.95.
The Alpha Dog comes with a very nice metal headphone stand. I liked the stand so much that I enquired as to whether MrSpeakers had any plans to make it available as a separate, purchasable accessory. Unfortunately, at the present time it will only be available with the Alpha Dog. My only quibble with the stand is that, if the Alpha Dog cable is attached (which is how most folks use their headphones), the stand isn't quite high enough to keep the cans from sliding off due to the angle and weight of the cable. I used a two-inch piece of closed cell foam placed on the top of the stand to raise the headphones up so the cable would clear the bottom of the stand. While the MrSpeakers website recommends this solution for using the stand with the cable attached to the Alpha Dog, it would be better if a foam riser were included with the headphones.
The Alpha Dog's earpads deserve special attention. They are large, soft, easily removable, and designed to completely envelop your ears. I suppose if you had exceptionally large ears, you might find their inner space constricting, but I found that not only did they completely surround my ears, but I also had some flexibility in their placement. Moving the earpads position will have an effect on the sound, both in the harmonic balance and overall clarity, so I recommend that prospective owners try different fittings until they find one that best suits their tastes.
I wear glasses. There are many headphones that I like very much, but they require that I remove my glasses so that they can make a better, more complete seal around my ears. The Alpha Dog headphones, while more comfortable sans eyeglasses, still make a good seal even with glasses on, due to their thick, soft, compliant earpads.
Unlike many earphones that rely on a single cable connection point (usually on the left side), the Alpha Dog headphones have dual connectors, one on each enclosure. For some users, this dual connection scheme may be cumbersome, but it offers one major advantage over single connection methods: you can switch the left and right channels by changing the cable connections. I occasionally come across recordings with channels reversed, and switching the cable on the Alpha Dog is far quicker and easier than rooting around the back of my preamp or DAC to reverse the cables.
The Alpha Dog can be used with either a standard single-ended termination cable or a balanced termination cable. Switching from one cable to another shouldn't take more than a couple of seconds, due to the Alpha Dog's well-designed connectors. The review pair came with the single-ended cable. I used the Alpha Dog headphones with a variety of sources, from the diminutive portable Astell & Kern AK100 to dedicated desktop headphone amplifiers, including the April Music Stello HP-100 and Sicphones headphone amplifier. While I preferred the desktop units when it came to overall dynamic slam and bass extension, the AK100 had more than adequate gain and power to drive the Alpha Dog headphones successfully.
With most headphones, the most important aspect of their ergonomic performance is their fit. While the Alpha Dog certainly isn't uncomfortable, it's not the most comfortable pair of headphones I've used. The primary reason that they are bested fit-wise by the Sennheiser HD 600 and Stax Pro Lambdas is because of the Alpha Dog's excessive side pressure. I don't have a large head (6 7/8 hat size), yet I found that, after wearing the Alpha Dogs for a while, I was very aware of how much pressure the headband was putting on the sides of my head. Although the Alpha Dog's pads are sufficiently thick that the headphones don't actually touch my ears, the pads do push rather forcefully on the areas around my ears. I suspect that some prospective owners with large heads might find this pressure uncomfortable. Due to the springy nature of the Alpha Dog's headband, you can't merely s-t-r-e-t-c-h out the headband to accommodate larger heads. Eyeglass wearers will notice the side pressure especially on their temples.
At 440 grams, the Alpha Dog headphones are not exactly light. While not as heavy as the 533-gram Audeze rosewood LCD-2s, the Alpha Dog is not the sort of headphone you will ever forget you are wearing. While the Alpha Dog does deliver decent isolation and could be used for commuting and travel, I suspect its size, shape, and weight makes it more suitable for home and studio use.
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