THE VALUE PROPOSITION IN COMPUTER AUDIO:  NUTS, BOLTS AND BUILDING BLOCKS – BUILDING A HOME FOR YOUR PLAYER SOFTWARE

PART 2: OPERATING SYSTEMS FOR LITTLE BOXES

INTRODUCTION

For use as a music storage and management system, server, renderer, and streamer, there’s still no substitute for a big box.  The x86 hardware platform can easily be built to amazingly high levels of performance, reliability, and utility for astonishingly low cost by historical levels.  So there’s no better or more practical choice for most of us than a traditional MOBO-based PC for a one box audio solution to house and manage our libraries, display data and art, and drive our playback endpoints on both LAN and WAN.

Yes, I know that there are many commercial streamer / players available, many of which are versatile and truly excellent at their jobs.  But this series is all about value in computer audio.  Almost all of the proprietary streamers & music management boxes are expensive and inflexible compared to a well spec’ed and built basic PC (whether Win, Mac or Linux), which is where those seeking great value in a computer-based audio system will find what they seek.  The same is true for those who already have a capable x86 computer (including laptops) that they use for multiple tasks and who want to add a computer audio management, control and playback system to what they have.  You can drop a lot of audio functionality onto an existing PC of any flavor, if it has the guts and capacity to do what you need.

Of course, there’s a disclaimer to the above.  The “all purpose PC” is a compromise much like the “all season tire”, which is

• somewhat better than summer tires in winter
• somewhat better than winter tires in summer
• far worse than summer tires in summer
• far worse than winter tires in winter

So you can add audio to your home or business PC and enjoy a lot of fine music.  But you almost certainly won’t have the best SQ, the greatest flexibility, the most comprehensive functions and features, etc if you use one box for all your computing needs.  And if your big box goes down, you have neither a computer nor music.  So a de novo music machine seems far preferable to me for almost everybody who can house, power, cool, operate, and afford one.  If you come to the same conclusion, I hope this series will help you make the choice between a big box PC (which includes laptops) and a little box single board computer (SBC) for your audio front end.

If you can and are willing to parse your computer audio work stream into functional bundles, a little box can carry a lot more of that load than you think with no compromise in sound quality or functionality…..and at stunningly low cost.  The concept of a single board computer is key here – it means that the entire computer (including ports, memory, audio, video, graphics etc) is built on a single circuit board.  This is not a new concept – the first commercial one dates to 1976.  And today’s motherboards carry a lot of onboard functionality that was entirely peripheral for years. Even today, when onboard AV is pretty good for general use on the better MOBOs, you have to add audio and video cards for truly high performance sound and graphics.

Although there are many fabulous MOBOs out there, a single board x86 is impractical even with the best MOBOs because of the need for RAM.  There have been a few MOBOs with onboard RAM, but they garnered almost no interest or market share.  ASUS made a few with 2G and later 4G of RAM  without expansion slots 6 or 7 years ago, as I recall.  So for our purposes, there are no SBCs on the x86 platform, and the SBC descriptor is (for all practical purposes) limited to the small fry of the computer world.

There are dozens of single board computers out there today (summary here), of which many have audiophile use potential.  The Raspberry Pi family is currently the most popular of the SBCs used for audio, and for good reason – they’re inexpensive, made better than the price point suggests they should be, reliable, easy to set up and use, and supported by a huge web presence of enthusiasts many of whom are knowledgeable and experienced (and, of course, many of whom are useless or worse).  The Raspberry Pi Foundation is an excellent source of help, and there’s strong support from the Linux world for each of the many distros available for the Pi.

When it came out, the Pi was a very basic little device that was designed and marketed for educational use.  It was created by a man named Eben Upton (who’s been many things over the years, from Director of Studies at Cambridge University to a Broadcomm chip designer) to counter a drop in the number of students enrolling in computer science courses.  He was struck by the number of kids who wanted to learn about and work with computers, but who had no access to anything beyond a game console because of cost.  The story is fascinating – read about it here if you’re interested.

Remember that this discussion is aimed at audiophiles.  So we’re not going to get into computing basics, despite how amenable SBCs are to DIY tweaking, coding and modification. As most SBCs boot and run from an SD card, it’s hard to break or brick them. Just burn a new image onto a card & start over.  So these are wonderful for learning, experimenting, and tweaking.  But first, you have to choose one and make it work as its designers intended.

SINGLE BOARD COMPUTER BASICS

Most single board computers are set up, configured, and operated the same way.  Those that run on a Linux-based OS (which is almost all of them) have a default OS that’s available from the website of the organization(s) behind it.  And there are SBC versions of many top Linux distros available from either the parent organization or an offshoot, e.g. you can download Ubuntu, Ubuntu Server, and more than a few variants like Mate for SBCs with an ARM processor directly from the Ubuntu site. 

At last count (per Slant), there were 56 SBCs (including variants with distinguishing features) on the retail market.  A few are known to be great for audio, and more than a few are clearly not up to the task.  Some, like the Pi Zero W, are great within their limits but lack features many of us find essential. Some appear to have more potential than anyone has realized, although I can’t find any discussion of their use in audio.  

Despite that fact that I love y’all more than I can say, I wasn’t willing to buy one of each and set them up just so I could report on whether they’re in the running.  So some of my reporting is based solely on specs and the anecdotal experiences of friends.  I don’t consider this approach to be seriously flawed, as (from extensive experience with SBCs) specs and capacities strongly suggest how well a device will perform in an audio setting if it has similar design, construction, components, etc. And I don’t discount the value of ingenuity in making little boxes do things they weren’t designed to do.  Just remember how hard it is to get a quart into or out of a pint bottle.

A WORD ABOUT SUPER SBCs:  Some SBCs are actually mini-x86s or other powerhouses disguised as competitors for Pis, ‘bones etc.  I suspect that the credit card sized UP and slightly larger UP Squared would be great for audio, but they’re a lot more expensive than the Pi.  Yes, they’re essentially single board computers, but the UP is powered by Atom and the Squared version comes with a choice of Celeron, Pentium or Atom and has both M2 and mini PCIe slots.  They’re almost certainly more capable than a Pi for audio use.

The Udoo Bolt comes with a dual or quad core Ryzen processor running up to 3.6 GHz and will run up to 32G of DDR4 2400 RAM..  The specs strongly suggest that this is a serious audio machine waiting to be tapped. The downside is that the lesser version costs $332 and the greater one $418 – so it’d have to be pretty darned good to justify that price.  But it should run the Linux distro of your choice and serve as a fine ROCK alternative with Roon server on it.  I’d love to get my hands on one to see what it’ll do, but there are other items higher on my list (e.g. a MiniDSP UDAC 8).

There are a few other “super” SBCs out there, and I expect a steady stream of new ones for the foreseeable future.  But for me, none of the currently available ones is worth its cost for audiophile use in any capacity. I do not recommend these when a Pi 4 with 4G of RAM is only $62 list and as low as $50 when on sale (which is often).  If you want a tiny PC, I’d strongly consider a NUC or one of the sticks or minis from Azulle, Intel ComputeStick, Gigabyte, Asus etc.

SBC ROUNDUP

Pictured above are 5 of my 7 Pis (along with my original Beaglebone Black MPD music server in the black metal case on the right with the centered RJ-45, exactly as designed and described so well by Chris ‘way back in 2013). The ports and USB plugs give you an idea of just how small these devices are.  Here’s a table of the most popular ones, in ascending order of street cost (all available at the stated price as I write this).  Some of these are probably waiting for us to discover how great they are – but none offers the combination of power, price and performance that you can get in a Pi 4 with 4G of RAM.

A POSTSCSRIPT ABOUT ARDUINO  This is a hugely popular system with its own tiny, cheap hardware – it’s the namesake of several project boards and systems you can find on the Arduino website.  But (like the BBC:micro) Arduino is not technically a microcomputer - it’s a microcontroller, which is a microprocessor-based device designed to control other devices using an embedded system that may be externally or internally stored.  Yes, it has a CPU on board, but it cannot serve as anything close to a general purpose computer without hardware and software add-ons.  In my opinion, it’s simply not worth the cost and effort to do this, as you’ll end up with a series of painful compromises and it won’t do anything really well.  Microcontrollers may have their memory, ports, etc onboard or on an external storage device.  Arduino has its own programming language and is generally used to control devices like signage, medical appliances, lights, etc.  There are a few rudimentary audio programs for them, including one that’s basically an R2R DAC – and you can program one to play back WAV files.  They’re fun to play with, but no audiophile will be using a microcontroller as a dedicated component in his or her listening system.

THE SBC GOLD STANDARD FOR VALUE & PERFORMANCE – THE RASPBERRY PI 4

Let’s start with the bottom line: for my money and ears, the latest Raspberry Pi Model 4 with 4G of RAM is the best buy in small box solutions for audiophiles.  Bone stock and running the latest Raspbian (the Foundation’s recommended OS), a Pi 4 is a very capable little computer that will run the ARM instance of JRMC very nicely.  It’s still probably not enough to run a Roon server or core, but they don’t offer that download anyway (yet) – so it’s a moot point right now. You can make some wonderful music with a Pi 4. You can also turn it into a Wifi hub at the center of its own WLAN with an Ethernet connection to the web (instructions HERE and elsewhere on the web – it works).  You can make an electronic crossover from a Pi for a multiamplified speaker setup (example HERE), recognizing that you’ll need a MC DAC with enough output channels for all the individual drivers just for 2 channel reproduction. You can even make your own NAS with a Pi and a USB HD (see HERE) 

The Pi 4 has several useful features for audiophiles, including

• a 64 bit quad core CPU
• gigabit ethernet
• 4 USB ports (2xUSB2 and 2xUSB3)
• dual band ac WiFi
• Bluetooth 5 & BLE
• separate busses for USB and networking
• an upgraded GPU

It’s the first Pi to perform in the same league as lesser x86 boxes and can easily be the heart of your own LAN / WLAN multiroom music system.  Just add USB or networked file storage, networking hardware, and endpoint players for a whole house system you can control from your mobiles, PC, etc.  You can even use Alexa and her friends for control, e.g. activate the House Band skill in Alexa to control JRMC.

Benchmarks confirm the Pi 4’s ability.  Magpi’s published results show the Pi 4 to be 4 times as fast as the 3b+ and 10 times as fast as the Zero or Zero W on Linpack benchmarking.  Their Speedometer 2 testing of browser speed shows the Pi 4 to be twice as fast as the 3b+.  The 4 also has about twice the memory bandwidth (R/W transfer rates to and from RAM) and 3 times the Python GPIO speed as a Pi 3b+.  These numbers show it to be equal to many respected Intel and AMD based PCs that are only a few years old – and it blows many highly touted tablets and smartphones out of the water.

The 4 is a transition piece in many ways.  Like the ever growing Porsche air cooled 6 as it evolved well beyond 3 liters, the Pi 4b is being pushed hard enough to start crossing its design limits; even without overclocking, it’s now running fast enough to heat up the CPU and GPU in normal use – it really benefits from a cooling system of some kind.  A better case is essential for audiophile use, even if it’s only as a player.  

I use the FLIRC fanless aluminum case, a very attractive one in which a Pi 4 never gets above 73C in 23C ambient room temps.  In ambient temps >80C, you’ll need some kind of active cooling – see the test linked below for a discussion of case cooling.  If you keep it in a cabinet or other area with limited airflow, you definitely need a good case to keep it cool. Here’s an online summary of case testing to help pick one.

A SMORGASBORD OF Pis

The Raspberrry Pi family is fantastic for audiophiles on a budget or otherwise wanting small, simple, inexpensive solutions for their needs.  At their price, you can use several to create a networked audio system of very high quality and sophistication, e.g. use a 4b with 4G of RAM for your server, another as your NAS, and a combo of 4s and ZeroWs as needed for your endpoints.  Use another 4b as an electronic crossover and multi-amplify your speakers.  The most useful models are discussed below, to help you pick those that will meet your needs.

I’ve tried every Pi I own (which includes ZeroW, 3b, 3b+, and 4) in every audio role it would handle, from JRMC core to simple endpoint player.  There are now 9 Rpi boards in circulation, but you only need to consider 3 of them for audio use.  The PiZeroW is a $10 wonder that will serve you well as an endpoint / player and deliver great SQ up to 2 channel DSD with the right players.  The Pi 3b+ is even better as an endpoint and will serve your audio files just fine despite a sluggish GUI.  The 4b with 4G of RAM is an outstanding little box that will run a server like JRMC just fine and deliver great SQ even for MC DSD.  Here are more details:

The PiZeroW

• a tiny $10 board complete with a 1GHz single core CPU, a Cypress CYW43438 chip for 802.11n and BT4, plus OTG microUSB2 and a separate microUSB power port
• A ZeroW is a simple endpoint renderer / player for WLAN use; in that role, it’s great!
  • If you want a Roon endpoint, you’ll need to use a Squeezebox variant because Roon Bridge won’t run on the Zero’s 32 bit ARM 6 build;
• Installing an OS and associated apps (players, communications etc) can be a bit tricky on a ZeroW, since you need a network connection, there’s no LAN port, and the WLAN0 interface is unconfigured on installation; 
  • The WLAN can be preconfigured by editing the config files on your computer before first boot to include a wpa_supplicant config file – if you don’t do this, you could chase your tail for hours;
  • You can also get it to work by setting it up on a Pi with a wired network connection (3b+ & 4 both worked well for me) exactly as you want it to be on the ZeroW, then moving the SD card to the Zero; 
• There are some wonderful operating systems and players for the ZeroW.
  • Remembering that the only way in for audio files is your WLAN, SQ is excellent;
    • all those below are clearly better than the optical output from Chromecast Audio into the same DACs with Redbook FLACs through my AKG 701QJs.
      • Highs are cleaner and better defined, bass is tighter, with cleaner articulation / resolution of multiple parts on everything from vocalists to acoustic stringed instruments to jazz combos to big bands and orchestral pieces
    • SQ on good FLACs & 2 channel DSD is right there with the Pi4 and any of my x86 based systems;
      • SQ through my iFi DSD DAC driven directly by my ROCK NUC may be very slightly better – blacker space, more coherent “assembly” of those well articulated individual parts, and slightly bigger bass with no more bloat;
  • Most of these are lightweight distros built on Debian or another Linux flavor
    • Be aware that these are basically JEOSs (Just Enough Operating Systems) that do not install with package managers, file editors, and many other command line utilities prized by Linux users; you have to know what you’re doing to color outside the lines drawn by the creators of each – and it’s not necessary just for audio
    • You only need a 16G microSD card for any of them, but I got a pile of high speed 32s and 64s cheap on sale, so I use them for everything;
      • Most of these systems automatically expand the files system on first boot
  • PiCorePlayer  is an excellent choice for a ZeroW endpoint. It includes a highly configurable Squeezebox setup that works very well for me as a Roon endpoint
    • Once you get on your WLAN, you can set everything up to your liking and control the system easily from devices on your network with a browser using the web GUI
    • It plays 2 channel DSD flawlessly but I wouldn’t push it to MC at high rates
    • There is a Squeezebox server in PCP if you need it.
    • I haven’t gotten PCP on my ZeroW to show up as a JRMC zone yet; I”m still playing with this;
  • Max2Play is a great choice for audiophiles using a ZeroW
    • Max2Play is a Debian based operating system packaged with several very useful apps and features for audiophiles
    • Easy installation of Max2Play on a ZeroW is enabled by using the onboard WiFi as a hotspot (name max2play, password mypasscode) so you can use a smartphone to configure it; this is the default startup mode on initial boot & it works great!
    • Once you use your mobile to set up your LAN, you can do everything else from the web GUI or SSH
    • There are currently 15 audio plugins available
      • Squeezelite, BT & several others install with the system when you select the “advanced” configuration default (which I strongly suggest to start)
      • MPD is an available plugin
      • The Audioplayer plugin installs Squeezelite, Shairport, and GmediaRenderer
      • The Bluetooth plugin adds a GUI for BT setup and management
      • The HiFiBerry plugin sets up and interfaces with all HiFiBerry Pi sound cards
      • There are DLNA and Squeezebox server plugins
      • There’s even a Spotify Connect plugin
  • DietPi is a light and flexible operating system with extensive configuration options
    • The main advantage of DietPi on Pi 3b+ and 4 is the simple built-in GUI for installing all kinds of software, including Roon Bridge and multiple music players
      • This is less useful on a Zero, which won’t run many of their packages (HERE)
    • I ran DietPi on a few 3 endpoints and like it a lot; but I prefer PiCorePlayer on a 0;
  • Raspbian is the default OS from the Raspberry Pi Foundation and works quite fine; use it if you have trouble getting the others up and running; it’s very easy to install, although the CPU is slow enough to take almost an hour to download and install all the available updates (which you do not need to do just to play music);  it’s plenty fast enough for audio playback
    • It  installs with VLC so you have a good player immediately
    • BT audio works fine for “noncritical listening”
    • You can only drive a USB DAC from a Zero by using an OTG (“On The Go”) dongle or cable;
      • The two identical-appearing microUSB ports are NOT identical; the one on the end is for power only, while the one next to it is the OTG port; you can only use the inner port to drive a DAC and you can only do it with an OTG adapter or cable;
        • OTG requires that pin 4 (the “sensing pin”) of the USB cable be grounded to set the device in “host” mode; the easiest way is to buy an OTG dongle;
          • You can make an OTG cable yourself by opening the female end of a male microUSB to female USB cable and soldering pins 4 and 5 together; BE CAREFUL and don’t accidentally connect anything but 4 and 5 to each other;
  • Volumio is well known to the AS community and a fine system for audiophiles using the most popular ARM devices.
    • It’s a music management system in a JEOS with an MPD back end
      • Think of it as an MPD server and client package
    • It’s LIGHT! Volumio loads entirely into RAM
    • It’s up to date    
      • supports I2S DACs, web radio and other goodies
      • does DSD, DoP, MC, DSP on more robust Pis
      • Zeros will give you great 2 ch DSD & DoP but can’t do the fancy stuff
    • It’s maintained well with effortless over-the-web updates
    • It’s easy to install & sets up its own hotspot on initial boot (like Max2Play) if the device you’re using has no LAN port
    • It easily mounts CIFS and NFS network locations from the GUI
    • The browser-based GUI looks good & works well from any mobile device I own
    • The developer has downloads for Pis, Odroid, Sparky, and Asus Tinkerboards
  • RuneAudio is another nice little MPD-based playback system embedded in a JEOS
    • I’ve used it extensively on BBB and Pi, but I only loaded it on a Zero to make sure it works……..it does!
    • There are other systems out there that should please audiophiles, but the above are the ones I’ve tried on a Zero.

The Pi 3b+ (NOT the 3b!)

• This is a worthwhile improvement over the 3b for several reasons
  • gigabit ethernet, dual band ac wifi, and a faster 4 core processor (1.4 vs 1.2 GHz)
  • the $5 you save by buying a non-plus model 3 (if you can find one) just isn’t worth it
• In addition to those I described for the Zero, there are a few other OS / player / music management packages out there that are great on Pis from 3b on up. (and on other similar ARM boards)
  • A Pi 3b+ is up to the task of being a JRMC hub, although the graphics are a bit slow
    • It streams over WAN with almost no issues - my son claims it dropped a few times in a year, but it’s never happened to me & I’ve streamed from this box around the world
    • The ARM version of the software is more basic than the x86 versions, but most of us can live with it very well because it sounds great
  • Roon Bridge runs perfectly on it.
• I have NOT upgraded my multiple 3b players to 4s because I don’t think the 2 ch SQ from my lone 4 is any better than it is from my 3s; when I get a good MC DAC and can try MC DSD, I expect the 4 to be better (and will upgrade the 3s if it is)
• If you have friends who just had to upgrade to 4s and are giving away their 3s, take them all and don’t look back!

OTHER MUSINGS ON A PI

• If you already have a media server and need endpoint players, you’ll love a Pi (or ten).
  • A PI 4 with 4G of RAM makes a fine music server if your software package is not graphic-intensive and you don’t need heavy duty DSP, transcoding etc.  And it will do anything you want it to do as a renderer / endpoint.  If you’re really pushing it and all 4 cores are pumping iron, it can get hot enough (80C+) to trigger automatic throttling back to 1GHz from its usual 1.5GHz in the “official” case (a plain Jane thin plastic shell that’s as attractive as it is protective).
    • Remember that the earlier Pis ran at lower speeds, so they’re inherently “throttled” compared to a 4; when the 4 throttles back, it’s still better than a 3b+;
  • I wouldn’t stray below the 3b+ for audio, since they still cost only $35 or less and have more of what you need than the 3a or b (e.g. processor speed, 4 USB vs 1). 
  • You have to use a DAC with USB or HDMI input.  There’s no other digital output port.
  • The 3b+ is powerful enough to do DSD, MC, mild DSP, and some graphic-intensive retrieval and display of album art etc – but it will run hot at full tilt without a good case to help keep its cool.  I haven’t tried high res MC, but it’s remained cool, calm and collected in a good fanless aluminum case with heatsink pushing stereo DSD512 into my iFi and SMSL USB DACs.
  • My ZeroW is a fine little player for stereo – I’ve tried VLC, Kodi, and a few MPD clients and it plays RB FLACs well on all of them.  Roon Bridge won’t run on it, so you have to use Squeezelite (e.g. PiCorePlayer); It is the original 90 pound weakling, so everything happens more slowly (except playback, of course). It can’t handle much DSP or sample rate processing, but it’s a natural as a general purpose player for mp3 and Redbook FLACs in all but the most critical listening settings.  

• If you want to build a system from scratch, you’ll love multiple Pis.
  • A Pi4 with 4G of RAM will happily retrieve your audio files from either USB or network storage and pump them directly into your DAC and/or into your network at any currently used resolution in up to 7.1 MC.
    • In this role, you’ll have 2 way traffic on either your ethernet port or your USB bus;  If you store your music files on a USB HD, you’ll also be driving your DAC from the USB bus.  
      • As USB 2 is fine for music transfer, you can use USB2 for the HD and USB3 for the DAC or vice versa.  But the PI4 can only supply a maximum of 1.2A to all four USB ports at the same time. So you have to power either your DAC or your HD externally if you choose the all-USB route.
      • The Pi 4 has great gigabit ethernet and excellent WiFi.  So I use NAS for my files and a DAC is the only USB device connected to the Pi. I have two Pis on ethernet and two on 5GHz WiFi, all running both JRMC and Roon Bridge with equally excellent SQ; yes, SQ is infinitesimally better (I think) directly from ROCK by USB;
  • I’ve been running a full JRMC installation on a Pi 3b+ for a few years without a hitch
    • The GUI is slower on the 3b+ than the 4, and waiting for some visual transitions can get a bit annoying.  But it’s never faltered in audio playback, even when streaming over the internet to my son’s system 7 miles away while I listened to different program material from the same device.
    • JRMC25 for ARM processors works fine and should keep almost anybody happy on a Pi 4.  I have 26 on my PC, but it’s not out yet for Linux or ARM.
  • Don’t forget the other cool stuff you can do with a Pi for audio and music; you can
    • Make an active crossover
    • Make your own WiFi hub with or without internet connection
    • Make your own synthesizer
    • Make a digital audio workstation
    • Make an oscilloscope  (or this one)
    • etc etc etc

OK – I admit that I may be a bit prejudiced in favor of the Pi over other SBCs.  But that’s only because I’ve been using it alongside its competition for a few years now and it’s simply the best I’ve found and the most reasonably priced.  It’s probably the most used SBC platform in the world for audio and audio-related use, with a ton of support, software, and hard stuff for it.  The development team continues to support and update it regularly and it’s probably not going anywhere for a long time to come.  And even at $55 for the 4G Pi 4b, it’s a true bargain compared with the others (see the table at the beginning for detail).

And if you want to push it to its limits, you don’t have to go rogue to make it even better because the Raspberry Pi Foundation has already issued firmware updates to keep the CPU and GPU cooler under heavy use.  With the official firmware update, you can “overclock” the processors with a simple change in the config.txt file that will not violate the warranty, as long as you don’t push it past 2.1 GHz.  And if you do this, you get a 20+% improvement in Linpack benchmark scores over the stock 1.5 GHz Pi 4.  Keep in mind that this is not like rooting or jailbreaking a mobile device – it’s all designed and sanctioned by the Raspberry Pi Foundation and keeps your Pi within “factory” spec limits.

BEAGLEBOARDS AND BONES

Many of you are probably aware of Chris’ pioneering efforts in the SBC-based music device arena.  Although I was (and remain) amused at his statement in a 2012 post that “Linux is great but...[a]verage computer audiophiles have no chance setting up a Linux machine ;~)”, I was overjoyed to find that he’d apparently revised his opinion somewhat within the year.  The Raspberry Pi was just coming out at the time and the Beagleboards were the gold standard for inexpensive SBCs.  Both ran a light Linux variant, but the ‘bone was by far the more powerful of the two and much better suited to audiophile use.

He really started the Beagleball rolling when he published How to Build a Beaglebone Black MPD Music Server on July 7, 2013.  I and many others followed his excellent instructions to the letter and ended up with a wonderful little music box built on a Beaglebone Black board powered by Debian Linux and driven by MPD.  It had ethernet, USB, and HDMI, which, in 2013, was serious kit – WiFi wasn’t a serious omission, given the cost, size and performance of the device.

There were other B’boards at the time, just as there are now.  But the Black was the right combination of size, cost and capability for the time – and it’s still useful, although even the latest versions are a bit behind the Pi 4.  There’s an “enhanced” version of the Black from SanCloud that comes in 4 variants (all with WiFi) from a basic 512M at $55 to an industrial strength version with 4 G for $89 that’ll hold up to extreme use conditions.  I’ve never been able to break my ‘bones despite some really hard attempts to do so, which suggests that this one is bulletproof.  

Neither the Beagleboard Green nor the xM is a good choice for audio.  The xM’s too expensive for what you get, and B’board Green doesn’t have the horsepower to pull this wagon.  There’s now a wireless variant of the Black, and that’s what I’d get if I wanted another ‘bone (which I don’t).

I don’t think you can do better for audio from a ‘bone than to follow Chris’ instructions, even today.  There are many distros for the ‘bone, and I’ve tried them all.  There was even a developer version of JRMC for it for a very brief period of time, and it played great (even though the GUI was grossly challenged).  I’ve run Ubuntu for Beaglebone and it’s OK if not spectacular.  The latest OS images from BeagleBoard.org are Debian based and quite reliable – I see no reason to stray from them.  

Having said that, I do like RuneAudio and Volumio on the BBB. The current download works very well, especially considering that the ‘bone is still living in the megahertz world and has only 512M of onboard RAM.  I wouldn’t go out and buy a BBB today to do this, because the PI 4 is better in every way and cheaper (even with a good case and power supply).  But if you have or inherit one, do NOT throw it out! You always need at last one more player.

If you just want a fine 2 channel server / renderer, you can’t do better than a BBB with MPD plus a client, or with Rune or Volumio. Mine ran continuously for about 3 years with MPD as my main music server without interruption (except when I experimented with it) or failure (which never happened, despite some egregious attempts to get a quart out of its pint bottle). After each science project or play session, I just stuck the original card back in and it resumed its iron stance without a complaint.  It’s still powered up and makes great music as we speak.

OTHER SBCs YOU MIGHT CONSIDER

You can get fine sound from several SBCs.  Each has its own support group and infrastructure, although I haven’t found an audio community of users anywhere close to those around Raspberry Pis and BeagleBones.  And you’ll have to find an operating system that supports your audiophile needs.  

The Cubieboards are (were?) robust little SBCs using chips from Allwinner.  I don’t know if you can still buy them new, but their website remains updated and active – so they’re probably out there somewhere.  If so, you might consider one if you’re adventurous. The latest version of which I’m aware is the Cubieboard 9, a 64 bit quadcore 900MHz ARM v7 with 3G of 64 bit DDR3 RAM, 16G eMMC,  dual band ac Wifi, BT 4.1 and a pair of 4k HDMI ports. Strangely, ethernet remains 10/100 only.  Cubies come loaded with Android (!), but you can also download and install either a Debian image or an Ubuntu distro developed and optimized for ARM by Linaro, an industry association of major players in the ARM market like Qualcomm, Google, Fujitsu, Comcast, Samsung, Red Hat, and TI.  

I can’t find a new Cubie to try, but with Linux on board it’s probably a capable device for audiophiles if the price is right.  There’s an international support group but I can find no one who’s into audio on the Cubies. I did find a reference to it on the Volumio site, to wit “Volumio runs on most embedded devices (Raspberry Pi, UDOO, Odroid, Cubieboard, Beaglebone...)” - but the only named downloads for ARM devices other than ‘bones and Pis are for Odroids, Sparky and the Tinkerboard.

Cubox is a totally different device that’s not part of the Cubie family above.  It was one of the first microcomputers and was the inspiration for the original “cube computer” movement (cube computers today are no longer tiny).  It’s another ARM device, but it’s uniquely stuffed into a 2x2x2” housing, so you don’t have to buy a case for it.  The flagship Cubox i4P is similar in specs to a Pi3b – it’s a 1GHz quad core CPU with 2G of RAM, “n” Wifi and “gigabit” ethernet (limited to 470MBPS) – and MSRP is $120.  

Most importantly, it has optical S/PDIF audio out, which will be desirable to many audiophiles and is simply not embedded on most SBC boards.  If you need optical audio out, the Cubox becomes cost effective against other SBCs that will require a hat or convertor for optical output in addition to a case.  

Cuboxes run Android or Linux, and there are many distros of the latter available for download HERE.  You should have no problem putting Roon Bridge or any of the great Linux players available today on your Cubox.  I can find no audiophile community of Cubox users, so support and feedback are limited.  But they’re so similar to the other ARM-based SBCs that you should have little or no trouble porting the info available about Pis into Cubox-speak.

ADDITIONAL THOUGHTS ON ALTERNATIVE SBCs

DietPi is available for Odroids and Pine boards, along with a generic “other” distro that doesn’t work on Beaglebones and has no support.  But you may have to look long and hard to find a suitable OS for some of the off brands before you can set them up for audio.

You can almost always add repositories for software packages to a Linux distro or derivative, if you know how.  So you can probably load at least one or two of the players I described in an earlier chapter of this series from the command line after you install a package manager like APT.  But you won’t find much support for the lesser known and used boards and you may be out there all alone.

But if you happen to have one or come across one at a great price, there’s no reason not to go with it.  Use the guidelines above for Pi Zero vs 3b+ vs 4b to decide how you might best use a given SBC.  The Rocks are solid performers with excellent specs, although I don’t think any of them has onboard WiFi.  Odroid makes some powerful little boards as well, again without WiFi and at higher cost than a Pi 4.  And the latest OrangePi boards are both price- and performance-competitive with Pi 4b but lack support (especially from OS developers).

END NOTES

Most of you have no idea what it was like to program for a vacuum tube device that had about 5K of total memory and ran so slowly you could beat it with an abacus.  I learned to code in 1965 on an IBM 1620 for which every single transaction was another straw on its already bowed back.  Efficiency in coding meant the difference between an hour of runtime and 2, and even a tiny redundancy could cost the university a lot of $ in lost computer time.  The best coders wrote programs that ran much faster and delivered clear output in more usable formats than those of the rest of the pack.  

Today, we’re so spoiled by RAM, CPU speed, thread counts, HD capacity, communication speed etc that we don’t even notice how poorly written many programs are that we use every day.  Those websites that load more slowly and have to be navigated like rapids in a storm are still annoying, and they don’t have to be that way.  But coders spoiled by a world of plenty very often fail to develop that edge that makes programs fly.

SBCs are limited in their capacities, abilities, and tolerances.  They’re a different animal from the x86 boxes most of us use for daily computing, and they have to be approached with a different philosophy.  Know and respect those limits, because every bit counts.  To get the most from SBCs, you have to optimize everything and cut no corners.  The speed of every internal bus affects performance.  USB ports in SBCs can only deliver a specific amount of power before they starve the connected clients.  A rise in temperature of only a few degrees can affect CPU power, and poor physical connections in cables etc can be equally devastating.  Splitting processor capacity between audio and graphics requires intelligent resource allocation to make sure SQ is maintained at the expense of the GUI and not the other way around.  A lot of this is done for us by the developers of some of the better operating systems, servers, renderers, and players – but it helps a lot to understand what’s going on and keep an eye out for anything that could slow or degrade performance.

Do not scrimp on the ancillaries.  SD cards are getting faster, and they’re worth it. You don’t need huge cards for audio – 32G is plenty, and you can get fast microSDs from well known vendors for as little as $20.  If you have USB 3, use USB 3 drives and communication peripherals.  Use good power supplies and connecting cables.  Respect the radius when bending and respect the receptacle when plugging or unplugging – SBCs have their port hardware mounted directly on the board, and the joints are usually none too sturdy.  Use only as long a cable as you need.  Hold them by the connector ends when inserting and removing.  Dress cables well - a rat’s nest is an unsightly invitation to disaster of one kind or another, from crossing them up after unplugging a device to starting a fire.

Everything that’s important to know and do when using a big computer box is much more so with an SBC.  They have limited capacity, limited reserve, and limited tolerance to misuse.  They’re like your teeth – you only have to take care of the ones you want to keep.