Extreme high-end headphones are big and bulky, except this one

I'm a lucky guy, I've reviewed most of the world's state-of-the-art headphones, and they're all big, head hugging over-the-ear designs from the likes of AKG, Audeze, Beyerdynamic, Grado, Hifiman, Sennheiser, and Stax. The Abyss AB-1266 is the biggest headphone I've ever worn, and the best-sounding headphone I've had a long-term relationship with.

Then last year I reviewed a new, much smaller Abyss headphone, Diana, and while it was awfully good, it wasn't in the league of those aforementioned very best full-size headphones. Close, but no cigar.

Abyss is an upstart headphone maker rapidly advancing the state of the art, so now there's a second Diana: the Diana Phi. It looks the same, but the Diana Phi's insides are different. It features a new version of the mighty AB-1266 Phi's driver, and the sound tuning has been refined.

The Diana Phi's handmade, real leather ear pads are larger and a different shape than the original, still-in-production Diana's. To cut to the chase, the new Diana Phi is the smallest ultra-high-end planar magnetic headphone I've ever tested (not counting the Audeze LCDi4, but that's an in-ear model).

Diana Phi's impedance is rated at 32 ohms. Its very flexible cable is five feet long, and it's fitted with a standard 3.5 mm stereo plug and a 6.3mm adapter, or a 2.5mm, four-pin XLR, or 4.4mm balanced plug. The headphone weighs 12.3 ounces and comes with a beautifully finished canvas carry bag.

Abyss headphones and their drivers are all designed, machined, finished, and hand-assembled in their Lancaster, New York factory. The Diana is $2,995, Diana Phi is $3,995, and the AB-1266, now called the AB 1266 Phi TC, is $4,995.

Listening to the two Dianas

They look alike, but what about the sound? Well, both are highly transparent and pure, and the bass is deep with excellent control. Original Diana is no slouch, but switching over to Diana Phi, the sound is more vivid, the soundstage expands, and it's more clearly focused. Thanks to the new larger ear pads, I found the new Diana a little more comfortable over long listening sessions. Owners of original Dianas can upgrade to the new pads, which run $175 a pair.

The Diana Phi sound is more incisive, so I could more clearly hear how George Harrison was "bending" his vocals on Within You Without You from the latest high-resolution Beatles Sgt. Peppers album. I never before noticed the extent that he was mimicking the sitars' sounds. Harrison never sang like that again.

On Paul Simon's So Beautiful or So What? album, the instruments, especially the percussionists, were more cleanly separated and distinct from each other. It sounds like a better mix over the Diana Phi.

I was spellbound by Chan Marshall's sultry vocals on her latest Cat Power album, Wanderer, with a set of Audeze LCD MX4 headphones. The sound balance was warmer, mid bass was richer, the music was more "organic" than what was coming from the Diana Phi. The MX4 was my Headphone of the Year in 2018, but switching over to the Diana Phi, Marshall's vocals came through with more presence -- I felt like I was at the session. Thanks to the Diana Phi's superior dynamic punch, the music sounded more alive; cymbals sounded airier and more detailed. The MX4 was more relaxed -- it took the energy down peg or two. Both headphones have very potent, cleanly defined low bass.

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The MX4 does have one clear-cut advantage over the Diana Phi: the MX4's higher sensitivity makes it a much better match to portable, battery-powered music players and phones. The Diana Phi does its best at home with the Mytek Brooklyn, Pass Labs HPA-1, and best of all, the Luxman P-750u headphone amp.

The extreme high-end headphone market is getting mighty crowded, but near as I can tell, the Abyss Diana Phi doesn't have a direct competitor. Nothing this small sounds this good!

As for the really large Abyss AB-1266 Phi TC, it's still the one to get for headphone buyers craving the very best.