I got comfortable in the center chair. I was visiting British manufacturer Arcam in their new facility, a few miles north of Cambridge, and product manager Andy Moore had set up a modestly priced but potentially good-sounding system in the company's dedicated listening room: KEF R300 speakers driven by the Arcam FMJ A19 integrated amplifier, which had impressed Stephen Mejias in the January issue. The source appeared to be Arcam's FMJ D33 D/A processor, which I reviewed in February 2013, connected by USB to a laptop running JRiver Media Center.
I closed my eyes, and Moore played a track from the soundtrack to one of the Batman movies. The soundstage was wide and deep, and the orchestral sound was detailed and uncolored. This was an unfamiliar room, system and recording, but I was impressed by what I was hearing. I opened my eyes and saw that the laptop wasn't being used. I turned to Moore to ask what we were listening to, and he pointed to his iPhone 4S. "I'm streaming audio to the Arcam rBlink with Bluetooth!"
Yes—sitting atop the D33 was an rBlink. Sam Tellig had reviewed this $249.95 Bluetooth-connected D/A processor in the December 2013 "Sam's Space." I have expressed my reservations about Bluetooth's lossy audio codecs many times in Stereophile, most recently in that same issue's "Letters," so it is an understatement to say that I was gobsmacked by what I was hearing—especially as, unlike some Android phones (see http://tinyurl.com/qhxjv3o), iPhones and iPads don't have the potentially superior-sounding aptX lossy codec, but use AAC at 128kbps (iOS6) or 256kbps (iOS6+ onward). (Because a Bluetooth wireless connection has insufficient bandwidth to handle uncompressed two-channel audio data of CD quality, which requires 1411kbps, some sort of data compression is necessary to stream audio via Bluetooth (footnote 1). Low Complexity Subband Coding (SBC) is the default codec in the A2DP Bluetooth profile.)
"It gets worse," laughed Moore. "I was streaming the file from Spotify."
Now my face was even redder. Spotify's Premium service, which was what Moore was using, uses the lossy Ogg Vorbis codec running at 320kbps. I've written before about the sonic dangers of cascading lossy codecs, ie, where one encoding/decoding cycle is followed by another. To encode a datastream, a codec breaks it down into blocks of variable size; when the results of two or more codecs are cascaded, it is extremely unlikely that the timing of each of these blocks will coincide. As a result, transient information that might occur at the intersection of two blocks can get spread out in time and sound.
My experience suggested that Arcam must be doing something special with the rBlink's Bluetooth circuitry. Rather than buy ready-to-use OEM modules, Arcam is a Bluetooth licensee and is thus able to use the latest Bluetooth chipset, to which they apply their own dejittering technology. Their use of aptX is probably helped by the fact that aptX developer CSR is based nearby, and the two companies' engineers sup their warm English beer in the same pubs. The DAC chip is the Texas Instruments PCM5102.
Perhaps I shouldn't have been surprised by my experience at Arcam. Stephen Mejias reported, in his November "Entry Level" column, how impressed he'd been with music streamed from Ms. Little's iPhone to the NAD D3020 amplifier. But I needed to audition the rBlink in more familiar surroundings. I asked for a review sample and, in the opposite of my standard practice, ran it though my usual suite of measurements before I did any listening.—John Atkinson
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COMMENTS
John, I'd be interested to see Stereophile spill a little ink on Bluetooth solutions that handle AAC directly. The potential advantage is that the player can (and will) stream the file--unfettered--to the other end and the "Bluetoothness" aspect becomes irrelevant for those who buy music from the world's largest online music seller, or make the effort to choose AAC over some other lossy format before putting songs on their phone, regardless of brand or OS.
Deckeda, that sounds cool but I'm not familiar with that possibility. Can you link to some products that do so, or any technical writings or forum posts that point to this possibility?
On another note, though I am duly impressed with the rBlink, glad there is a Bluetooth receiver that has proper measurements and a digital out, etc. the elephant in the room is the Apple TV. Using Airplay, you can use your wifi network (no pesky 25-foot rule - don't have to be on the same floor) and stream losslessly. How do ya like them apples? The obvious limitation is that you have to be using Apple devices, excluding a few workarounds. But if you're using an iPhone/iPod touch, a Macbook Air or Pro or iMac or what have you, Airplay is there and it does 16/44.1 and 16/48 losslessly. The Apple TV has an optical out and no analog out, so it's only for the DAC crowd, but it works great and has Ethernet and Wi-Fi. It's also notable that is is only $99 new rather than $249.
Mr. Tellig, it appears you use an iPhone, so I'd love to see you try out an Apple TV. Return it if you are not pleased!
All that said, I have a dead simple Bluetooth radio in my bedroom that I use plenty for listening to podcast while I clean up or send audio from JRiver to it using JRemote. Choice is a beautiful thing.
I'm sorry but I don't know where I read it. This review got me researching aptX because I'd read the earlier hosanas about it here. That's when I learned all aptX transmissions require the transcode through the "aptX codec".
Somewhere in there is when I also read that AAC gets sent as-is (assuming an AAC file source) and decoded at the Bluetooth reciever.
I'm sure the devil's in the details and especially so with cheap transmitters and recievers.
**********
In my experience, AirPlaying music over to an AppleTV is a recipe for despair. All of them necessarily resample to 16/48 and likely, not terriby well. But 16/48 is ideal for most video sources, so there's that. More to the point, it's never sounded good to me for music, and not by a little bit. Could also be an issue with what happens when the audio gets sent out of the HDMI or TosLINK since ATVs lack their own DAC.
AirPlaying over to my Marantz receiver (built-in AirPlay) is just dandy, as is any AirPort Express, which keeps everything at 16/44.1 bit perfect. And by the way these comparisons were done on the same stereo system.
But I'm with you. If your source is 16/44.1 via either iTunes on a computer or iOS device, an AirPort Express is, and has remained for 10 years, the defacto no-brainer streaming solution for both ease of use and sound quality.
Wow, thanks for the tip. I had no idea. Makes perfect sense for video but not good for audio.
Here is some objective verification (yes, measurements included) and details about the current Airport Express for you, Tellig, Atkinson or anyone else! The SRC will downsample up to 24/96 to 16/44.1 - seems fair enough to me. In my case I'm using an Oppo (and later a dedicated DAC) for DLNA with JRiver so this would be more for myself or my GF being able to play Spotify, podcasts, internet radio etc. quickly and easily without any extra fuss, sending the optical out to a DAC.
http://www.computeraudiophile.com/content/465-new-apple-airport-express-bit-perfect-still-limited/
http://www.computeraudiophile.com/content/466-measurements-first-and-second-generation-apple-airport-express/
The summary:
- 16 bit / 44.1 kHz music -> Bit Perfect
- 16 bit / 48, 88.2, 96, 176.4, 192 kHz -> Not Bit Perfect but does play through the AE at 16/44.1.
- 24 bit / 44.1, 48, 88.2, 96, 176.4, 192 kHz -> Not Bit Perfect but does play through the AE at 16/44.1.
Howver, it's nothing new. The original AirPort Express, and 2nd gen (updated to 802.11n) behaved similarly: take most any PCM and give you 16/44.
Chris at Computer Audiophile noted why this is, despite the new AE having a 24/192 DAC. It's the AirPlay standard that limits audio to 16/44. Nothing higher ever leaves the sending computer or iDevice. Doesn't matter how you setup a computer. AirPlay stipulates a transcode on the fly to Apple Lossless 16/44 regardless of the file you're playing back.
You can get the original AE used, from eBay for $40 or less and it'll be just as good as the new one for audio. Windows users might be OK as-is. Mac users would need an OS no newer than 10.7 to configure it, or a script that lets later versions of OS X run AirPort Utility 5.6.1 (The second gen AE, also likely inexpensive now, can I think still be configured with AirPort Utility 6.3)
Just avoid Bluetooth if you want to pick on it's limitations.
You cannot make a silk purse out of a sow's ear.
It's like putting wings on a car and saying it doesn't fly very well!
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