HEDD Audio’s HEDDphone D1 are near-perfect open-back headphonesGerman brand HEDD Audio has a reputation for producing quality monitor speakers, but took a bold leap into headphone monitoring more recently in 2020 with the £1479 HEDDphone One — a flagship offering that was subsequently updated in 2023 with the more compact Two model.

READ MORE: Steven Slate’s VSX Immersion One headphones are making me consider selling my speakers

The new D1 open-backs offer a more affordable entry price and attempt to rival the fast transient response of planar magnetic headphones — popular for mixing and mastering — by using an innovative dynamic Thin-Ply Carbon Diaphragm developed with Composite Sound of Sweden. And they put my own planar headphones in the shade.
Image: Press
Unboxing and wearing the HEDDphone D1
The D1s come in a soft-shell carry case that’s not oversized, plus a pouch for the two-metre cable. Like many high-end cans, the cable connects to the headphones via dual 3.5 mm mini-jacks, and so balanced output would be possible with the correct cable and DAC/amp, if you’re so inclined. Impedance is 32 Ohms, meaning these will work happily with audio interfaces and laptop headphone outputs. You don’t need a fancy external headphone amp.
Strapped in, the D1s are supremely comfortable, even for a glasses wearer. There’s just the right enough clamping force to support a solid bass extension, plus a generous depth to the ear cups that helps to avoid over-heating while also enhancing immersion — something this particular set of headphones excels at. Long sessions are possible without discomfort, as the headphones almost seem to disappear.
Image: Press
What does the HEDDphone D1 sound like?
The sound signature has gloriously fizzy highs, verging on being too harsh at times but bringing out incredible detail in vocals and hi-hats in the same way as the AMT tweeter on HEDD’s monitor speakers. HEDD’s co-founder Freddy Knop himself likens this sound to the AMT tweeter in a Head-Fi forum post, citing a “good kind of obsession with detail and transients, precision, realism”. As time goes on, I grow increasingly impressed with the transient and colour detail of the highs on the D1. It’s a quality that creeps up on me and, swapping back to my planar daily-drivers —the (admittedly-cheaper) Hifiman Sundara open-backs— I’m shocked at how trashy and anaemic the treble presentation suddenly appears in comparison to the HEDDs. The D1s also take the lead in comparison to other dynamic-diaphragm models at lower monitoring levels, where the sound remains just as defined in the high end.
At the opposite end of the spectrum, there is plenty of bass extension too. Many open-backs are shy of bass out of the box —planars especially— so this helps kicks and sub-synth bass lines to really come alive. Additionally, this bass heft is extremely handy when performing playback translation checks in virtual rooms using software such as Realphones and Space Replicator as the frequency balance is more speaker-like. All great so far.
The mid-mids and low-mids are a little too bulky to my ears, leading to a slight nasal honk, and a low-mid build-up similar to the effect of placing studio monitors on a desk. Gentle cuts with a simple graphic EQ at 500 Hz and 128 Hz clear things up nicely. This is relatively trivial to achieve on my own audio interface that can host headphone EQ in its DSP, but might prove annoying to those who don’t have such luxuries. Post EQ, music is more enjoyable to listen to and mixes translate better as I don’t try to either scoop the low mids as much to reduce vocal proximity, or cut murky resonances around 500 Hz too severely.
Image: Press
Hitting the target with HEDDphone D1
High-mids are as revealing as the treble range, with ample articulation on kick beater clicks, under-snare mics and fuzzy electric guitars. To my taste, this ultimately appears brash and so I revert to my normal EQ preference — dialling in a Harman target curve. I tend to use a Harman curve for a standardised approach to monitoring, I enjoy the fuller bass and the smoothness of an evened-out mid and treble range. It helps with translation checks, too. I locate some Harman target settings for the D1 in an Audio Science Review forum post and, with a parametric EQ applied there’s a dramatic difference in tonal quality. Granted, results appear less exciting, but they’re far more suited to applications of mixing and mastering. I’m in my happy place.
And back to the subject of immersion. HEDDphone D1 has one of the best spatial representations of any headphone I’ve listened to, with an amazing sense of depth, and a surprisingly expansive stereo field. Opposite-panned, crunchy electric guitar layers spring to life and stretch into the far distance in one of my go-to reference tracks — Gethsemane by Richard Thompson. Meanwhile, minutiae in panning decisions are revealed in contrasting, synth-layered tracks. Once again, my Hifimans are outclassed by a clear margin, and to be frank, I’m left reeling.
Image: Press
HEDDphone D1 vs. the world
Mulling over competitors, the HEDDphone D1s outshine Neumann’s NDH30 for a more pleasurable listening experience, and are slightly more pleasing than Audeze’s MM-100 planar open-backs for tonal character and spatial presentation. Meanwhile, Hifiman has multiple planar products in a similar price range, often with steep discounts on outgoing models to give you even more for your money.
For producing, composing and enjoying music though, the HEDDphone D1 is difficult to beat and never gets uncomfortable. Throw in a little EQ help, and the D1 becomes a trustworthy mixing and mastering workhorse that’s articulate and revealing throughout the entire frequency range.
Image: Press
Key Features

Open-back headphones
Thin-ply Carbon Diaphragm (TPCD) dynamic drivers
Frequency Range: 5 Hz – 40 kHz
32 Ohms impedance
2-metre, removable unbalanced cable
Soft-shell carry case
Weight: 350 g

The post HEDD Audio’s HEDDphone D1 are near-perfect open-back headphones appeared first on MusicTech.