The HEDD Audio HEDDphone D1 enters a fiercely competitive landscape of open-back audiophile headphones, promising reference-grade accuracy through cutting-edge driver engineering. Designed as a lighter, more accessible alternative to HEDD’s earlier models, the D1 aims to deliver uncompromising detail, natural spatial imaging, and a studio-ready frequency response without the bulk often associated with high-end engineering. Whether you’re a critical listener, a mixing professional, or an enthusiast searching for a headphone that prioritizes realism over theatrics, the HEDDphone D1 presents itself as a serious contender. In this review, we break down its build quality, driver design, and overall sonic performance to see how well it justifies its place in the premium open-back market.
What You Get
- HEDD Audio D1 headphones
- Detachable textile-covered cable with 3.5mm connectors
- Quarter-inch adapter
Look & Feel
The D1 is very reminiscent of Sennheiser’s HD600 line in terms of build. It’s definitely a bigger headphone than those, but they’re also a lot lighter. Being familiar with how large and unwieldy some of HEDD Audio’s products are, the D1 is a welcome change of pace, and thankfully, it does not sacrifice build quality. The frame of these headphones feels refined, making the build feel like one static piece that doesn’t swivel. What really sticks out is the padding. The D1 features a thick headband and earcup cushions that are made from soft foam velour. They are extremely firm, encompassing a good portion of your head. They feel secure without any significant pinch.
Design
The HEDDphone D1 centers on a custom dynamic driver built around a Thin-Ply Carbon Diaphragm (TPCD), an advanced composite diaphragm material (used in aerospace and high-end engineering) chosen for its low mass, high stiffness, and minimal distortion. The TPCD allows for significantly faster, cleaner transients and more accurate resonance control than conventional diaphragms, giving the headphones unusually detailed, balanced, reference-grade sound. Its impedance is only 32 Ohms, making it significantly easier to drive than other HEDDphones.
Soundstage
Having listened to the past several headphones from HEDD Audio, I was expecting a similarly large soundstage and precise imaging from the D1. While there’s a lot that can be said about just how accurate the D1 is with its localization, there’s no theatricality to it. When it comes to stereo width, the D1 feels fairly standard. The left and right channels extend with a fine reach, giving the headphones an open headspace that allows for non-linear spatial properties, but the D1 never feels very holographic. Spatial accuracy exercises pinpoint precision, but instrument positioning is super strict. Everything gets nailed down to its exact position without much movement. This doesn’t let the D1 communicate much distance between instruments, even though the separation is great. The imaging just gets pushed to the front, letting you know where everything sits in an easy-to-understand way.
I don’t think anything about this presentation negatively affects my enjoyment of the D1 in any way. While there might not be much musicality to this soundstage, everything that plays through it feels true. It’s one of the most naturalistic soundstages I’ve heard in a while, which is the kind of performance I think HEDD is going for here. It’s rare to find an open-back headphone in this price range not trying to constantly impress you with how open and wide it is. The D1 sticks to basic width, but impresses with realistic imaging that makes the space believable without any artificiality to it.
Low End
This is not the kind of headphone that will give you consistently exciting bass impact. The D1 has fullness and detail to it, but it lacks a gruff vibrating texture that offers that immediately gratifying bass tone. Just like the soundstage, the D1 isn’t going for theatricality here, but it can still be relied upon for clarity and detail. There’s a level of finesse to it that allows for a fast response time, making bass notes more individualized and tactile. It won’t always have an underlying presence to it, but it shows persistence and grace when it needs to, leaving plenty of room for depth and dynamism to take hold.
Mids
The midrange is where the D1 shows you what it really has to offer. You’ll come away from it thinking this is how every headphone midrange should sound. It retains the same level of purity that the bass offers, but the mids are given a big push in volume to really showcase their extension. You don’t need to pay close attention to the harmonic content to understand how detailed the frequency resposne here is.
Everything feels like it’s being put under a microscope, extracting micro-detail and artifacts that blow right past you, listening to other headphones in this price range. It’s a level of breathless transparency that is hard to replicate, exhibiting a natural timbre in each note being performed. Sometimes headphones with this level of midrange accuracy can come off as cold and clinical, but the D1 doesn’t. It retains sincere resolution while adding just a touch of warmth to extend musicality.
Highs
You’re getting a raw performance from the treble, but it’s completely unfatiguing. High-frequency information presents itself naturally, with tons of detail in a controlled space. Everything resolves with height and even features a subtle ring that feels smooth but never rolls off suddenly. There’s a light sizzle that doesn’t tail off with any sparkle. It remains clear and even while in good balance with the rest of the sound signature.
Summary
The HEDD Audio HEDDphone D1 stands out as a headphone crafted for listeners who value precision, realism, and tonal purity above all else. Its cutting-edge TPCD diaphragm delivers exceptional midrange detail, clean transients, and an uncolored sound signature that feels genuinely natural from top to bottom. While it avoids the exaggerated width and booming low end of more theatrical open-backs, the D1 compensates with superior imaging accuracy and a refreshingly authentic presentation. Combined with its lightweight build, plush velour padding, and easy-to-drive 32-ohm impedance, the D1 succeeds as both a professional tool and a refined audiophile experience. If you’re searching for a headphone that captures music with honesty and depth, without sacrificing comfort, the HEDDphone D1 is one of the most compelling options in its class.
The HEDD Audio HEDDphone D1 is available at Audio46.
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