Roon Labs Nucleus+ music server

Sssssshhhhhh—I forget what music was playing, but as the sound faded away, I could hear a loud hissing coming from the 2011 i7 Mac mini I was operating headless with Roon 1.3 to play files over my network. Checking the mini’s shared screen on my MacBook Pro revealed that it was completely unresponsive, so I yanked its AC cord, after which it wouldn’t boot up.

This was the second time the Mac mini had died. The first time, in 2015, the local Apple Genius Bar had repaired it. This time, the hipster at the Genius Bar turned me away: “We don’t offer repair work on vintage computers.”

But I’d become addicted to the Roon app. The loss of its host computer was almost an existential crisis.

Vintage Computers
In 1967 I had a summer job working in an electronics lab. Whenever we had a problem that needed to be worked out on a computer, we would present it to a gentleman in a white coat, who would code the problem on punch cards, then disappear into an air-conditioned room to which we “civilians” were barred entry. A few days later, I would receive a printout of the result. That was my first experience of working with a computer.

In 1981, I bought a kit from which to construct a Sinclair/Timex ZX81 computer. Housed in a small plastic case with a plastic-membrane keyboard, the ZX81 was based on a Zilog Z-80 8-bit microprocessor chip and came with 1kB of RAM, which I upgraded to 16k in order to run larger programs that I’d bought or written in the ZX81’s BASIC language. That was my second experience of working with a computer.

In 1983, I bought a BBC Micro Model B, which used an MOS Technology 6502 8-bit microprocessor, had enough RAM to be useful, and could be used with 5¼” floppy diskettes. I wrote programs in both BASIC and machine code; by 1985, using a tagged text language I’d written, I was producing on the Beeb most of the editorial content for Hi-Fi News & Record Review magazine. That was my third and formative experience of working with a computer.

But becoming involved at such a deep level in personal computing required way too much time. Over the years since the 1980s, particularly when it came to using a computer as an audio server, I’ve been working with ready-made solutions—eg, the Antipodes DX Reference, Aurender N10, and NAD Masters Series M50.2—in which all the heavy lifting of optimizing a general-purpose computing system to work as a dedicated server for playing audio files has already been done.

Yes, I’ve recently been tempted by the introduction of low-cost computer-on-a-board systems such as the Raspberry Pi, the various Arduinos, and Intel’s NUCs—but there’s that time-sink problem again. The closest I got to rolling my own server was installing Roon on my Mac mini—and you know how that worked out.

Fortuitously, soon after my return from Apple’s Genius Bar, Roon Labs’ Steve Silberman called to let me know that the company was about to release its first hardware product, the Nucleus+ server. Would I be interested in a review sample?

I would indeed!

Enter the Nucleus+
Roon’s COO, Danny Dulai, visited in late February, bringing with him a Nucleus+. Priced at $2498, this uses an Intel i7 processor/NUC board and has 8GB of RAM and a 64GB SSD solid-state drive. The basic Nucleus costs $1398 and uses an i3 processor with 4GB RAM and a 64GB SSD. Both Nucleuses have a single gigabit Ethernet port, two USB 3.0 ports that can be used both to connect external drives and to feed data to a USB DAC, an HDMI port that can be used for both stereo and multichannel audio, and a Thunderbolt 3 port, so far unused. The Nucleus+ can output audio data simultaneously to more than six zones, one of which can be the iPad running the app. The Nucleus can cope with six zones.

The internal drive is not used to store audio files. Instead, as well as hosting the Roon Optimized Core Kit (ROCK) operating system and the Roon server software, it’s used to manage Roon’s library (footnote 1). From the outset, Roon was intended to produce a rich metadata experience. From the moment you point the Nucleus Core to the location of your audio library, the system begins to create the waveform display for every track; starts scouring the Internet for metadata, artwork, biographies, and reviews; and builds an object database. This means, says Roon, that “instead of storing data in the traditional tabular form, we model your music as a web of interconnected entities and their relationships to one another. . . . They enable us to perform complex queries that would be impractical for a traditionally architected application, and they let us perform background processing on your music library in order to continually improve the user experience.”

The basic Nucleus’s 64GB SSD can handle the metadata for libraries of up to 12,000 albums or 120,000 tracks; the Nucleus+’s SSD can cope with libraries with more than 12,000 albums/120,000 tracks. I thought I had a reasonably large library; Roon tells me I have 20,565 tracks. The Roon app asks you for a backup location for the library’s metadata. After three months of using the Nucleus+, my backup has filled 2.4GB—it’s going to be a while before the internal 64GB SSD is full!

Footnote 1: Though the Roon OS is based on Linux, all system functions other than those required to run the Roon server software are disabled. The Nucleus can’t, therefore, be used as a general-purpose computer.