HEDD: HEDDphone TWO Headphones

"Wow, I don't feel like I'm listening to headphones. They sound so open" were the universal reactions from mastering engineers at Infrasonic Sound and students at The Blackbird Academy that I witnessed when they tried the first production prototype of the HEDDphone TWO last year. At the time, my review of the original HEDDphone was in progress, but I hit pause on that assignment until I was able to get my hands on a full-production example of the TWO. Now that I've had the TWO model in my hands (and, more importantly on my head) for several months, let me un-pause.

While the original HEDDphone was a revolutionary product that offered an impressive listening experience like no other headphones, the HEDDphone TWO is a significant improvement in every way. What makes both models so special is HEDD's signature Air Motion Transformer technology. In my review of the HEDD Type 30 Active Monitors [Tape Op #118], I shared the story of how Klaus Heinz and his son Frederik Knop started HEDD in 2015, after the breakup of the ADAM Audio founding team, of which Heinz was the Director of R&D. Heinz had introduced the first iteration of his compact AMT tweeter design, a modern version of Oskar Heil's large and unwieldy pleated-diaphragm transducer, to the pro audio market with the release of the ADAM Audio S3-A monitor [#33], which I reviewed way back in 2003.

The primary advantage of the AMT driver is its ability to "squeeze/suck" air with far less excursion required than a planar-ribbon driver that "pushes/pulls" air directly, resulting in higher efficiency, faster transient response, and lower distortion. Throughout HEDD's speaker lineup, the AMT driver is used as a tweeter because scaling up a "folded ribbon" transducer to the size required to emit a convincing amount of bass energy in the open air would require large baffles and would be too difficult and costly to manufacture. On the other hand, HEDD was able to design an AMT transducer capable of full-range reproduction at headphone-listening levels within the restricted confines of an earcup with a closed interior and vented back.

I was utterly impressed with the refreshingly neutral and wonderfully detailed presentation of the original HEDDphone when I first heard it. Just like the AMT tweeters in my HEDD Type 30 monitors, the HEDDphone's full-range AMT drivers offered both a pleasurable listening experience and a high-resolution depiction of my mixes that I could trust. Unfortunately, bass reproduction wasn't picture-perfect. The lows were certainly there, but they sounded "soft" due to what I was able to confirm as poor low-frequency damping when I put the headphones on my test rig. Specifically, the original HEDDphone's AMT design was susceptible to resonance at frequencies below 100 Hz, especially when driven by a low-current or otherwise subpar headphone amplifier. Thankfully, HEDD alleviated this problem in the HEDDphone TWO's AMT with several improvements, including tweaks of the damping material and fine-tuning of what they call Variable Velocity Transformation (VVT).

Marketing terms aside, VVT simply means that the depth and width of the AMT diaphragm's pleats are varied in a specific pattern – to shape the frequency response, reduce resonance, and increase accuracy across the spectrum. My ears and measurements agree that ringing and harmonic distortion are reduced in the HEDDphone TWO's presentation at all frequencies – especially below 100 Hz – and likewise, transient response is significantly improved. Lows are now rendered with more punch, and highs are clearer, especially in the vicinity of 6 kHz, where the original version was lacking enough to sometimes hide sibilance. Mids and upper mids are there in vivid detail, as if the resolution was turned up for the all-important region where vocals, instruments, timbre, reverb, and ambiance reside together. When greater detail is revealed, placing elements in a mix becomes far easier, as does identifying collisions between those elements.

In short, the sonic presentation of the original HEDDphone was already impressive and unique, but the enhancements to transient response and accuracy of the HEDDphone TWO model make it even better suited for implementing mix decisions. Moreover, because the AMT drivers are quite large and are positioned as much around your ears as they are outside of them, the soundstage feels expansive – not limited to the space between your ears – which brings me to the "wow" reactions I mentioned at the beginning of the review. The HEDDphone TWO doesn't restrict the sonic image to inside your head. Instead, it sounds naturally open, much like a great pair of speakers in a well-tuned room. For all these reasons, the HEDDphone TWO is the headphone I choose for mixing, whether I'm in my own studio or working in an unfamiliar room.

Additional noteworthy improvements in the HEDDphone TWO include a 0.4 lb. weight reduction and a patent-pending suspension headband that's adjustable for size, shape, and clamping pressure. Granted, the new model is still a relative behemoth at 1.2 lbs., but the physical improvements make it comfortable to wear for many hours at a time. If you're in need of reference headphones, whether for mixing or for other moments of focused music listening, you really should experience the HEDDphone TWO for yourself. You can arrange a product demo at an authorized retailer through HEDD's website. Or, if you would rather try them at home, you can purchase them directly from HEDD with free shipping, a 100-day return policy, and a 5-year warranty.