Samsung Unpacked: Everything Announced Galaxy Buds 2 Pro Preorder Galaxy Watch 5 Galaxy Z Fold 4 Dell XPS 13 Plus Review Galaxy Z Fold 4 Preorder Apple TV 4K vs. Roku Ultra Galaxy Z Flip 3 Price Cut
Want CNET to notify you of price drops and the latest stories?
No, thank you

At last: Bona fide surround sound over headphones

Often promised, but the Smyth Realiser A16 really delivers a truly immersive experience over stereo headphones.

The Smyth Realiser A16, shown with a pair of headphones on top of the unit.
Smyth Research

Smyth Research is a UK based company that makes headphone surround processors. I reviewed its original A8 processor on this blog in 2010, and was thoroughly impressed by its ability to create truly immersive surround sound from stereo headphones. I've heard similar claims about Dolby Headphone, DTS Headphone:X, and countless other processors and apps, but in my opinion their promises never bore fruit. The original Smyth A8 did, and now there's a new Smyth Realiser, the A16 which can produce up to 16 channels of sound over stereo headphones. With the A16 headphones, they no longer sound like headphones, they sound like the multichannel home theater speakers in your room!

I was treated to an A16 demonstration at the CanJam NYC headphone show last weekend at the Marriot Marquis hotel. The room had 12 Yamaha HS8 powered speakers. I sat in the middle of the room, and the A16's inventor Stephen Smyth handed me a pair of tiny measurement microphones I inserted in my ear canals, Smyth then played an automated series of test tones over the speakers. Nothing was required from me, the A16 did all the work.

The system calibration took just a few minutes, and then Smyth played a few Dolby Atmos movie clips and music segments. One of the great things about the demo was that it was so easy to switch between the 12-speaker system and the headphones. Putting the headphones on automatically muted the speakers, and taking the headphones off turned the speakers back on.

Nearly everybody who heard the A16 demo at CanJam had a hard time at first believing the speakers weren't still on, the surround over headphones was that convincing. The A16's "head tracking" keeps the soundstage locked in place, so it doesn't move if you turn your head to the left or right. So for example, movie dialogue stays in front when you turn your head left or right. The A16 can also store sound "maps" of other rooms, so at some point it might be possible to put the sound of Carnegie Hall or the Lucasfilm Skywalker Ranch mixing studios in the A16.

CNET's Ty Pendlebury listening to the Smyth A16 at the CanJam NYC show.

Steve Guttenberg/CNET

Not only was the A16's surround immersion convincing, the height channel speakers placement were faithfully reproduced over the headphones. The center channel speaker's sound over headphones wasn't inside my head, it was projected forward to the actual location of the center speaker! Other than the original A8 processor, I've never heard any other surround over headphone demo that came even close to the A16's sound.

The A16 works with any stereo headphone, but the better the headphone the more convincing the surround illusion will be. Stephen Smyth likes Stax, Sennheiser HD 700 and HD 800, Hifiman and Audeze open-back headphones with the A16. The system is fully compatible with Dolby Atmos, DTS:X, Auro-3D and Ambisonics encoded recordings.

The A16's internal digital processor handles up to 24 bit/96 kHz audio. You can play one or two headphones at a time over the A16. The rear panel has four HDMI inputs, which limit the number of channels to eight, but pro users and mixers can access up to 16 channels via the USB input or 16 analog audio inputs. The A16 also has one optical digital input, two optical outputs, one Ethernet, one USB 2.0, one set of stereo analog RCA inputs, and two pairs of analog stereo RCA outputs.

The Smyth Realiser A16's introductory price is $1,690, £1,344 or AU$2,213 (not including headphones) and will go up to $2,000, £1,591 or AU$2,619 later this year.