Before I can get to what the Arvus H2-4D does and how well it does it, I have to explain why I think it's an important product. I spent years as an advocate for multichannel audio for music, based on discrete, lossless sources such as DVD-A, SACD, and high-quality downloads. All of these were either PCM or DSD and were accessible via a wide range of disc players, DACs, and local file playback apps.
I am well aware that the majority of Stereophile readers are not (yet) into multichannel, but two-channel and multichannel audiophiles have long relied on similar media and components. Some of us have added more channels. In parallel with this, the home theater world was committed to multichannel (or surround sound), but instead of DSD and PCM, they spoke multiple dialects of Dolby and DTS. Those oft-compressed formats required proprietary decoders for each dialect, which their developers were happy to license for use in AVRs and preamp/processors.
The entertainment industry noticed that the newer sound formats that support many horizontally and vertically arrayed sound sources, such as Dolby Atmos, Sony 360 Reality Audio, DTS-X, and Auro-3D, were natural for cinema and home theater, since they could create a more convincing experience of being present or immersed in the action. By applying these immersive technologies to music, the music industry could entice music buyers to purchase new equipment and music, including a back-catalog of music they already own in other formats.
I came away from the 2019 AES Convention fascinated by these new options for encoding, mastering, and distributing music. "Instead of multiple masterings and formats for binaural, stereo, and multichannel," I wrote in January 2019, "a single-format release can be played on any suitably equipped system." It would be the equivalent of a "single inventory" for the streaming and distribution sites for all formats.
It has taken almost three years, but Dolby Atmos is now permeating the music-streaming sites; note that most of the recent Grammy winners are available in Atmos.
Up to now, access to Atmos has been largely restricted to HT hardware; its success for music will depend on wide availability and non-HT options for audiophile music lovers to stream and to play discs or files in Atmos, especially in lossless versions (footnote 1). Enter the Arvus H2-4D.
What is it?
There are three basic sources for Atmos playback: web streaming from an app or a device like an AppleTV, local discs, and local files. But without an Atmos-enabled AVR or pre/pro, there has been no simple way to decode these streams (footnote 2). The Arvus (footnote 3) H2-4D is a simple solution to this problem. Its compact, nondescript 1U chassis contains an HDMI input and digital, analog, and LAN outputs. It decodes and renders all extant varieties of Dolby (including Atmos), DTS (including DTS-X), and stereo and multichannel PCM (up to 24/192). The only front-panel features are a power switch and multicolor LED that indicates power, signal lock, and data format; once set up, it should require no user attention.
The rear panel contains, on the far left, a single HDMI input and a word clock input; on the extreme right is a place to connect a wall-wart power supply. In between is an array of outputs, all active simultaneously. The outputs include (from left to right): two HDMI pass-throughs (one full A/V, one audio-only), 16 channels of AES3 outputs via a DB25 connector, 16 channels of Dante outputs and inputs on a single RJ45 connector (footnote 4); 16 channels of balanced analog output via two DB25 connectors, and a data connection on RJ45 for setup and control via the local network.
A one-page GUI (above) is accessible from any device on your LAN, for accessing the Arvus from a computer, but I found my iPad most convenient. The GUI lets you select an input (HDMI, ARC/eARC, Dante) and a loudspeaker configuration. You can choose among settings for Mute, Standby, and Global Delay (useful for video sync), LAN settings, and individual speaker delays for each channel. There is also a Global Volume control, which is necessary if you are using output devices that lack that feature, as when you're feeding an array of active loudspeakers. (Essential as this is, it is not ideal: Tapping on a screen in 1dB increments is tedious; Arvus has promised new possibilities in the next firmware update.) The GUI also displays the firmware version, allows you to update the firmware with a click, and allows for a factory reset. It also shows the codec in use, which is useful, although it doesn't show the sample rate.
The H2-4D in my system
I set up a system to audition remote streaming, disc playback, and local file playback in Atmos, DTS-X, and PCM via the Arvus. For the input end, I acquired a Marantz VS3003 3 in/1 out HDMI Switch ($199), which supports the same audio formats as the Arvus. I connected the HDMI outputs from my Apple TV 4K, my Oppo BDP-105, and my PC/Windows-based streamer to the Marantz. The Marantz's output fed the input of the Arvus, and the HDMI output of the Arvus went to my Toshiba PC monitor so that I could see each user interface as it was selected.
My regular speaker system setup is 5.1, consisting of five full-range speakers plus a trio of subwoofers run via the BassQ controller. For this review, I added PSB Imagine XA and Atlantic Technology 44-DA Dolby-enabled speakers, relocated from my Connecticut to my New York City system, as front and rear height speaker pairs, respectively, each driven by a Parasound Zamp.
I began using the Arvus's AES3 outputs because my DACs have volume controls, and when the Arvus first arrived, its volume control had not yet been implemented. With the assistance of Mogami's Phil Tennison (footnote 5), I obtained a custom Mogami Gold AES TD DB25–XLR snake to connect to the AES3 connector on the Arvus. I then plugged XLRs 1–4 to the Okto DAC8 Pro and XLR 5 into a Mytek Brooklyn+ DAC. I assumed that software would route the appropriate channels through to the power amps, as would typically happen with a pre/pro. But when I switched everything on, with the Arvus set to output 5.1.4, I got 5.1 correctly—plus Front Height sounds out of the Rear Height speakers and nothing from the Front Height speakers. If I switched the Arvus to output 7.1.4, I got the usual 5.1 plus Rear L/R channels out of the Rear Height speakers!
Here's why. The order of the channels in Atmos world is fixed, and you must connect your DAC/amp/speaker to the correct physical channel even if the intervening channel cables are left unused. The Arvus was designed for studio professionals, who would know this. For reference, here is a list of the default AES3 outputs; the asterisks indicate channels used in my 5.1.4 channel setup:
1 Left, Right *
2 Center, LFE *
3 Left surround, Right surround *
4 Left back, Right back
5 Top front left, Top front right *
6 Top side left, Top side right
7 Top back left, Top back right *
8 Left wide, Right wide
Thus, in my setup for the digital outputs from the Arvus, outputs 1–3 and 5 went to the Okto for 5.1 and the front heights and output 7 went to the Mytek for the rear heights.
Later, after the central volume control was added to the Arvus, I used direct balanced connections from the two analog output connections using a pair of DB25-to-8XLR snakes. Of course, with analog, there is one XLR per channel; the ones I used are listed below.
• Balanced Analog (1–8): 1 Left, 2 Right, 3 Center, 4 LFE, 5 Left surround, 6 Right surround
• Balanced Analog (9–16): 1 Top front left, 2 Top front right, 5 Top back left, 6 Top back right.
Streaming Atmos with the H2-4D
I acquired an AppleTV 4K some time ago (footnote 6), for the express purpose of streaming Atmos from Apple Music; since then, the amount of Atmos content has exploded. Browsing the Classical repertoire, a randomly chosen recording is almost as likely to be available in Atmos as not.
I clicked on Sol & Pat. The Arvus recognized it as "Dolby Atmos (Multi-CH PCM)" at 48kHz, but to me the sound was completely new. The transition from stereo to "immersive" was startling. From the opening tambourine fanfare on through, the experience was much more "you are there" than the "we are here" of the stereo depiction (24/96 download, Alpha ALPHA757). The recorded, reproduced ambience completely replaced any awareness of my listening room. The two performers were steadfastly stationed up front, where they should be. I have no information on how the recording was mastered for Atmos—whether it was mastered for Atmos in the studio or by some automated process (footnote 7). Apple Music's Atmos is lossy (footnote 8), but I find it a credible alternative to the high-rez stereo release (24/96 in this case), swapping the latter's clarity and immediacy for a huge enhancement in the acoustic space. Moving to music that is already familiar in multichannel,
Footnote 1: Some music labels, most notably 2L, still offer discrete 7.1.4 channel files in WAV format for download. These can be played back on systems with the requisite number of channels without any decoding.
Footnote 2: Dolby offers desktop/DAW software licenses only for the professional market.
Footnote 3: Arvus is a 40-year-old independent company with deep ties to the music industry. Its earlier products include many loudspeakers and an 8-channel HDMI to AES3 digital audio converter that has long been described as "unobtanium" in the US.
Footnote 4: Due to a surprise visit from COVID, I was unable to use the H2-4D in a Dante environment, but I hope to do so soon.
Footnote 5: When I explained what I was doing, Phil swiftly realized the stock cables would not suit. "Normally, AES DB25 cables have 4 XLRs out and 4 in. Yours has 8 out, so it deviates from the normal configuration. More like a Tascam Analog cable using AES cable." He was right.
Footnote 6: In 2019, my Marantz AV8085 pre/pro was updated to support Atmos and Auro-3D, and I was greatly encouraged by the first immersive audio recordings I sampled.
Footnote 7: Mastering engineers have told me that these days an Atmos mix is an essential deliverable in most studios, which argues for the former for recent releases like Sol & Pat.—Jim Austin
Footnote 8: In Apple Music, lossless and Atmos are two distinct formats.
