Audio Streams #1

I'm the editor of, Stereophile's sister website devoted to computer audio. We review all manner of hardware, software, and music related to file-based playback, and offer helpful (we hope) "How To" articles as well as interviews with industry people—all designed to ease your journey to and through the world of computer audio. I envision my new Stereophile column, "Audio Streams," as an extension of this mission—and the addition of that trailing, plural s gives me some leeway to explore a wider range of hi-fi topics.

One of the main benefits of computer audio is that performance no longer must be traded for storage. The data capacity of the Compact Disc no longer applies, and increases in bandwidth and hard-disk storage have made moot the MP3's raison d'être of discarding information to save space. What this means for file-based music is that we now have direct access to studio-quality digital music. Websites such as HDtracks, Qobuz, and Acoustic Sounds sell high-resolution digital downloads—and now, along with the many high-definition reissues of classic recordings, new releases of popular music are showing up on these sites with greater frequency. When you couple this with the resurgence of vinyl, to say that we're living in a golden age of music reproduction is to understate the obvious.

In computer audio, we're confronted with myriad choices in the hardware we play our file-based music through, to the software we use to manage and play it, and even the kind of music files we buy. I've seen the word ecosystem showing up more and more in writing about computer audio, most recently with Neil Young's Pono campaign, and from a conceptual basis it strikes me as a sensible description, especially when we begin sharing our file-based music among hi-fis, among rooms.

The promise of file-based playback is one of great convenience wedded to high sound quality. The reality is that convenience and sound quality are still at odds. Two of the most annoying examples are Apple's refusal to support the FLAC file format, perhaps the most widely used for the distribution of CD-and-better-quality downloads; and Windows' lack of support for the USB Audio Class 2.0 standard, which permits the transmission of audio data with sample rates greater than 96kHz. While there are relatively easy workarounds for these gaps in each ecosystem, the reality is that, once we pick an ecosystem, we then need to learn how best to function within it.

I begin this month's "Audio Streams" journey with a company that aims to deliver on the seemingly improbable marriage of convenience and sound quality.

Bluesound (footnote 1) is a relatively new venture from parent company Lenbrook Industries, whose stable includes NAD and PSB Speakers. In fact, the engineering experience of these companies has been leveraged for the Bluesound line of products, which are designed to let you easily share music around your home. Think Sonos, with the added ability to play hi-rez downloads. (The Sonos system is limited to CD quality: 16-bit/44.1kHz.)

All Bluesound products share the same custom-developed Linux operating system, BluOS, and all are controlled by the free Bluesound app for iOS and Android devices. A smartphone or tablet is a mandatory piece of the Bluesound ecosystem.

The app easily allows you to group multiple Bluesound devices so that they play the same music—or each device can do its own thing. There are also individual app-based volume controls for all relevant devices. You can view your music collection by Album, Artist, Song, or New (most recently added). Playback is based on Playlists. You can create playlists on the fly or save them, add albums or individual tracks to a playlist simply by tapping on them, edit the order of songs in a playlist, or play the entire thing in Shuffle mode. Clicking on the Info tab brings up related artist/album information about the current selection, provided by (footnote 2).

All Bluesound devices support MP3, AAC, WMA, OGG, WMA-L, FLAC, ALAC, WAV, and AIFF file formats in resolutions up to 24/192, as well as gapless playback. Streaming services available to all devices include Deezer, Juke, Qobuz, Rdio, Slacker, TuneIn, and WiMP. Some of these services require a paid account, while others are available only in certain geographic regions. Each device includes a USB Type B mini port for product servicing. The Bluesound devices, exterior design by David Farrage, come in your choice of high-gloss white or black plastic with brushed-steel accents.

Bluesound Vault ($999)
In a nearly cubical case measuring 11.5" W by 9.3" H by 8.1" D, the Bluesound Vault combines 1TB of storage, a vertically oriented DVD-ROM drive for ripping CDs in FLAC and/or MP3 format, and a 24/192-capable Cirrus Logic sigma-delta DAC. Inputs comprise Ethernet, WiFi (802.11n), USB Type A, and, through an optional dongle, Bluetooth. Outputs include an analog RCA pair and digital TosLink capable of passing up to 24/192 data to an external DAC. The Vault will also recognize any network-attached storage (NAS) device, including shared network folders on your Mac or PC; at your discretion, it will list their music files in the app's library.


The Vault is the only Bluesound device that requires an Ethernet connection to your network and the Internet. Another feature specific to the Vault is that it acts as the Network Clock when used with other Bluesound devices, essentially ensuring playback timing among grouped devices. Because the Vault is also a network device, its contents are available from any network-attached computer—you can drag music files from your computer and drop them into the Vault to populate the latter's library. Ripping CDs is simply a matter of inserting a disc in the Vault's drive and waiting until it's ejected. The software does a good job of collecting metadata, including album-cover art; a 60-minute CD took about 10 minutes to rip.


For reference, a 1TB drive can hold about 3000 CDs in FLAC format. You can add additional external storage, either via USB (FAT 32 formatted) or Ethernet. From within the Bluesound app, you can also buy and download music directly to the Vault from (Geographical restrictions apply to most titles, but Bluesound is working on adding more download services.) It's worth noting that you can't edit metadata from using the Bluesound app; you'll have to do so from your computer.

Bluesound Powernode ($699)
The Powernode is a network player powered by an ARM Cortex A8 processor, a 24/192-capable DAC, and a 50W Direct-Digital Amplifier, all wrapped up in a case identical to the Vault's but slightly smaller (9.7" W by 6.9" H by 7.9" D). Inputs are the same as the Vault's, while outputs include two pairs of speaker binding posts and a subwoofer jack (RCA). According to Bluesound, "This is the same DAC/Amp technology that is part of our NAD Masters Series M2 DAC/Amp & M51 DAC, the NAD C 390DD DAC/AMP, and our new NAD D 7050 DAC/AMP."



Used in conjunction with the Vault, the music library in the Bluesound app will be automatically available to the Powernode—or, if running without the Vault, the Powernode can access your NAS.

Footnote 1: Bluesound International, 633 Granite Court, Pickering, Ontario L1W 3K1, Canada. Tel: (905) 831-6555. Web:

Footnote 2: See John Atkinson's review of the NAD Masters Series M50 digital music player in the May issue (pp.83–91), which is compatible with BluOS. The review included screenshots of the very similar NAD Remote app.—Ed.


monetschemist's picture

Michael, while I was sad to see Steven go, your appearance on the page is great news!

To the topic - why doesn't Apple support FLAC?

Instead of bashing Apple (or the less attractive option, supporting their choice), I exhort you to move in a Linux direction instead.

Linux is extremely compatible with FLAC. Not only that, it is extremely compatible with the urge to tweak - it is the hobbyist's dream

On my desk I have a lovely little CuBox-i4, which cost me about $125 and is currently running Voyage linux and mpd. The music is on a separate 3.5" 1TB WD Caviar Black hard drive which talks to the CuBox-i4 over e-sata. That "storage solution" cost another $125. The computer talks to my Schiit Bifrost just fine over USB. Together they produce lovely sound and can easily be controlled from my Android phone or tablet (or I guess from an iPhone but I don't swing that way). Hi rez files, no problem. mp3s, no problem. One day I will move the Schiit to desktop duty and put something more fancy in the decoding end of things, but I don't have a great deal of interest in changing the computer.

This is a great way to get into computer audio. Yes, it's not "off the shelf", but neither is a Mac with some kind of third party software like JRiver or whatever. It's really not that hard to get something like this going.

To my way of thinking, it's wonderful that FLAC is the dominant file format for purchased downloadable PCM music. It's open, no licensing fees, no worries about all that IP stuff. And a small inexpensive computer running Linux and mpd to play all those FLAC files - how can that not be the next step?

Why screw around trying to make your Mac play FLAC, when you can buy a wonderful small fanless computer that runs a libre operating system and software made to play FLAC files?

Or, heck, install Linux on your Mac! Now there's an idea!!!

yonk2's picture

You don't need to install Linux on your MAC. Just install the "homebrew" package manager from: open a terminal window and type: brew install mpd

It will download and build all the dependencies, and you're in business!

I'm going to use an old macbook and my Uber Bifrost (a VERY nice DAC) for the kitchen or MBR. The DAC in my main listening room is the Schiit Gungnir - my AMP (Wyred4sound STI-1000) has balanced inputs and with them the Gungnir sounds fantastic!


michaelavorgna's picture

Operating systems are simply an aspect of a means to an end - whatever works for you, works.

monetschemist's picture

Completely in agreement with you on that.

I was too wordy in any case, sorry!

By the way, I really appreciate your music reviews on AudioStream. I have listened to a lot of things, and bought a few, that I would not have otherwise learned about. Thank you for that.

michaelavorgna's picture

I'm very happy to hear you've found some new music through AudioStream. Cheers.

drblank's picture

I don't think anyone can really cover the reason why Apple doesn't support FLAC other than Apple themselves. They are the decision makers behind that one, but I do seem to remember reading articles on a Mac site many years ago (I couldn't find it since it's probably not even on the internet) that it was primarily due to how FLAC files handle Metadata, so Apple decided to come up with AIFF which is their lossless scheme and then ALAC, etc. I have also been told by many people that there isn't any different sonically from using AIFF or FLAC, so from that standpoint, if you are Mac user, get AIFF if you can and if you have FLAC, there are plenty of free apps that will convert them. I use xACT myself and I also rip files using XLD when ripping a CD to AIFF. I've had problems with some CDs when ripping and XLD seems to do a REALLY good job in that area. It's not the easiest to use software, but once you get used to it, you can set it up to work pretty easily, but it's got a LOT of weird options to sift through.

Also, if you store everything in iTunes, you can get third party player apps that support FLAC and DSD files, I just don't think they actually store the files in the iTunes library, but I haven't tried this, but this is another option to look at.

coach87's picture

Bottom line!
Here is my mission.
I am an apple guy but prefer to own my cd's and continue to collect and build my CD collection.
Most of my collection is ripped to mp3 but not currently distributed via a home network.
I have 2000+ existing Cd's and many more that are legally available to me.

I want the highest archival quality available.

I want to enjoy the highest digital quality throughout my home. Apple TV?

I am willing to ship my select CD's and have them burned for a fee.

Ripping additional CD's to my collection on the fly is a bonus.

1. Who Should Rip?
2. What is the best format and or storage/rip device?
3. How should I organize all of this data?

Thanks for your help.