Bluetooth Codec Support for Sprout


#1

Greetings:

One of the things that appeals the most to me about the Sprout is the blending of traditional (phono input) with the high tech (streaming Bluetooth). Unfortunately there is the lamentable fact that on the high tech side, adherence to certain standards and protocols greatly effects the end user experience.

The Bluetooth A2DP standard requires that Sprout support the SBC codec which can be a hit or miss quality wise depending in part on decisions made by the implementors of the source system. A2DP also provides for optional support of MP3, AAC and Sony Atrac. In principle a source could stream any of these without the necessity of transcoding if the target supports it.

I understand that Sprout supports the proprietary AptX codec. I believe Mac OSX and some Android devices have also licensed AptX. IOS devices, however, don’t seem to support AptX and Apple recommends that optional AAC codec be implemented on targets for the best IOS experience with iPads and iPhones. Linux systems can be made to support optional MP3 or AAC as well (with a bit of work).

So… any chance that Sprout support optional MP3 or AAC over Bluetooth streaming? If not, any plans for the future in this area? IMO Bluetooth audio streaming is already a bit of an ambiguous mess. It would be great if PSAudio provided clarity for it’s customers.

-Best,

/Andy


#2

Andy,

Thank you for asking this question. I ordered a Sprout for my nephew who just graduated from college. He has an iPhone, so I hope that the answer is “Don’t worry, it will all just work.” If not, at least I have a heads up. I never use Bluetooth so I have no clue about this at all. If there are issues, hopefully Scott can provide suggestions for a workaround, short of buying an Android phone . . .


#3

Magister… I can tell you (in broad strokes) not to worry that an iPhone will just work. Every Bluetooth device that supports the A2DP profile must support SBC so it will devolve to that codec under the worst case scenario. As an audiophile device, however, it would be better if it also supported the optional AAC codec (which is the default codec for iTunes). Even if it doesn’t support AAC, it might sound great transcoding to SBC but it would just be at odds with Apples recommendations (I’ll post a link to the developer PDF where Apple makes this recommendation if I can find it). There is at least one video kicking around where Scott actually links his iPhone to the Sprout via Bluetooth.

The A2DP profile and SBC particularly have been targets for many years with lots of people claiming that the quality is terrible and others claiming that the implementations are terrible and the basic codec is fine (like AAC and MP3, SBC has the ability to code at various bit rates with various resulting levels of quality). Many folks claim that a quality device with a proper SBC implementation will sound great.

On a related note, I believe that the iPhone IOS 7 now fully supports digital USB Audio so you can use a USB cable to feed a direct digital signal into the sprout for quality that surpasses anything you might be able to get with Bluetooth (source music quality becomes the limiting factor here). I believe this feature is relatively new to IOS, (the industry has had it for a long time).

If I got any of this wrong, I apologize, I’m an Android user myself…

/Andy


#4

No, you have it right. It’ll all just work, Android or IOS.


#5

The Apple Bluetooth recommendations for iOS document can be found at this link.

The relevant section I referenced above is: “2.2.5.2 MPEG 2/4 AAC Codecs”


#6

Andy,

Thanks for the followup and clarifications. Looks like everything will be OK.

Paul/Scott,

I think it would be a great idea to put together a PDF giving suggestions for getting the best sound quality with Sprout. I’m trying to persuade my nephew to pay some attention to SQ and not just accept whatever comes out of the iPhone. I know nothing about Bluetooth and so, for instance, Andy’s information about the possibility of using a cable (with iOS7) for better SQ is very interesting. And some people don’t know basic things that people in this forum do (don’t put equipment on a rickety shelf where the cat jumps on it . . . ). Looking forward to getting my (really his) Sprout next month!


#7

Andy, great post and very interesting.