Bluetooth AptX


#1

Hi,

Has anyone been able to get AptX to kick in while using bluetooth from a Mac?

Option-clicking the bluetooth menu shows the codec as SBC (it would say AptX if working).

Thanks!


#2

Don’t yet have my sprout but I had the problem with other AptX audio sinks and the Mac. What version of OSX are you running? You can try deleting the binding and trying again, that sometimes solves it. If not, there is a developer tool called the Bluetooth Explorer you can download for free that allows you to manipulate the Bluetooth Audio settings on a Mac. (I’ll find the somewhat arcane link and post it here). It has a pulldown under Tools/Audio Options that has a panel with the following options:

Screen-Shot-2014-12-03-at-2.26.52-PM.png

Checking “Force AptX” will almost always do it. Keep in mind that the Bluetooth protocol will still select SBC if the source down’t support AptX. “Force AptX” only applies if AptX is an option…


#3

I just realized that installing “Bluetooth Explorer” might be a bigger PITA for most Mac users. You need to download the XCode developers environment and then add the “Hardware IO Tools for XCode”. If you are up for it, go to https://developer.apple.com/xcode/downloads/ and then search for the “Hardware IO Tools for Xcode”. Download and install the Bluetooth Explorer from that. Sorry, that might be more work then a non software developer wants to be bothered doing…

/Andy


#4

Yeah. no AptX from iOS devices is a bummer. (I plan to use USB for my Mac.)

What portable devices support AptX at this point?


#5

The bulk of Android phones and tablets support AptX these days (around 70% of phones and 50% of tablets). It’s usually the low end Android devices that the manufacturers choose not to license AptX for. See: http://www.aptx.com/products/browse/categories

SBC with a high enough bitpool sounds almost the same to my ears as AptX. The problem is some devices scale down the bitpool and most devices don’t allow you to tune this yourself. SBC is a general purpose codec designed to scale down the bitpool if there is radio interference resulting in excessive retransmissions. AptX by contrast is fixed at a 4:1 compression and will sound good (or not sound at all!) under all conditions.

I regard the IOS SBC implementation highly so I wouldn’t worry to much about the lack of AptX support. (That said, I use an Android phone myself)


#6

Then that begs the question of Sprout’s implementation of SBC. Or does it? I don’t really have much knowledge of bluetooth.


#7

If Sprout’s A2DP SBC implementation conforms to the standards it shouldn’t be a problem. The standard indicates that all Bluetooth audio sinks (SNK) must accept all bitpool sides proposed by the source (SRC). When my Sprout shows up I’ll test the bluetooth implementation using developer tools and report out…


#8

Yes, I wonder why AptX with my Mavericks Macbook Pro doesn’t work with the Sprout. I can see it’s connected with the SBC codec. I know my macbook supports AptX since it works with my Nuforce BTR-100 bluetooth unit.

Is there a possible fix to get AptX to work with macbook either from the OS itself or a possible firmware update of the Sprout?


#9

I also tried the OSX bluetooth explorer option of forcing apt-X on, but it still only connects with SBC. Both the Sprout and BTR-100 seem to use CSR bluetooth radios, not sure why one works while the other doesn’t. I did read some other devices had trouble with Apt-X if multi-point is engaged. I wonder if that’s a potential problem since I did notice multiple devices could be paired with the Sprout simultaneously. I’m not sure if there is a way to completely reset the Sprout bluetooth so I can only connect it to my macbook pro to see if Apt-X may work in that case.

I’m wondering what Apt-X devices were tested to work with Sprout and how it was verified that Apt-X mode was actually engaged.

Anyone who has gotten Apt-X working (with some verification data is sent in Apt-X mode) with the Sprout please list what you’re using.

Anyone who has an Apt-X capable device but could not get it in Apt-X mode with the Sprout, please also list what it was.


#10

Ben:

My Sprout is due to show up tomorrow so I will report in more detail once I actually have one but here are some things to try:

  1. In addition to forcing Apt-X on in Bluetooth explorer, also set the initial and minimum bitpool options for SBC to 53 (leave max at 64).
  2. Disconnect your Mac from Sprout and reboot it to give the drivers a chance to reload.
  3. If you connect again after reboot and it claims SBC, bring up iTunes and play a track. Part way through stop and restart the track and check the Bluetooth settings for Sprout. Sometimes it will switch over to AptX.
  4. If none of the above works, disconnect the mac from sprout and bind two other devices (doesn't matter what codecs they support, any phones or tablets). I believe the Sprout only has memory slots for two bindings. After that, try rebinding the OSX box and try #3 again.
Good luck,

/Andy


#11

So one risk to giving advice is that sometimes it doesn’t address the problem ultimately. Having received my Sprout (full review pending a bit more listening) I tried my own advice (above) that I gave Ben. No dice on Mavericks anyway. Don’t know why and it’s proving hard to diagnose accurately. I know that Apple included AAC in their Bluetooth stack as an alternate A2DP codec in their latest OS.

So… anyone want to be the first to upgrade from Mavericks to Yosemite to see if (in addition to the AAC codec) it addresses the lack of AptX streaming with the Sprout?


#12

I have Yosemite on my MacBook. However, I wouldn’t know how to tell if my Mac is streaming AptX. I don’t know why one would use bluetooth for streaming from a computer. Why not use USB for higher resolution?


#13

I agree USB is so much better than Bluetooth.

I am also running Yosemite.


#14
fritzg said I have Yosemite on my MacBook. However, I wouldn't know how to tell if my Mac is streaming AptX. I don't know why one would use bluetooth for streaming from a computer. Why not use USB for higher resolution?
My plan is to use to use my iPhone/iPad to control Tidal via bluetooth on the Sprout. I guess I was not thinking I would be giving up lots of sound quality vs. using my computer via USB direct connect.

#15

Of course. The computer is hooked up via USB but it just irritates me that I can’t get AptX streaming to work from the Mac w/Mavericks, that’s all.

FritzG: To tell if your mac is streaming AptX, first you connect the Bluetooth to Sprout and begin streaming music from iTunes or another source. While the music is streaming you hold down the ‘option’ key and click on the bluetooth icon in the menu bar. There will be more information. If you select the Sprout from the list it will show the ‘Codec’ to be either SBC or AptX.


#16
stax said
fritzg said I have Yosemite on my MacBook. However, I wouldn't know how to tell if my Mac is streaming AptX. I don't know why one would use bluetooth for streaming from a computer. Why not use USB for higher resolution?

My plan is to use to use my iPhone/iPad to control Tidal via bluetooth on the Sprout. I guess I was not thinking I would be giving up lots of sound quality vs. using my computer via USB direct connect.


I’d think if you streamed Tidal via bluetooth, you might as well stream via Spotify and save $10 (or more)/month since not even AptX (which iOS doesn’t use) is CD quality. I’ve planned to us my to stream via bluetooth as well. Tidal is just too expensive, plus it won’t work on the old mac mini I have connected via USB and bluetooth streaming makes the higher quality irrelevant.

all that said, Im not a bluetooth expert, so don’t take my opinion on this as gospel. This is just the thought process I’ve gone through.


#17
andrewnewman said FritzG: To tell if your mac is streaming AptX, first you connect the Bluetooth to Sprout and begin streaming music from iTunes or another source. While the music is streaming you hold down the 'option' key and click on the bluetooth icon in the menu bar. There will be more information. If you select the Sprout from the list it will show the 'Codec' to be either SBC or AptX.
Thanks. I just checked and it was SBC. Is AptX supposed to automatic from Mac OS X? I haven't done any special install for it.

#18

MacOSX is supposed to have the AptX libraries built in and they should be used if the render (Sprout in our case and the “sink” in BT terminology) specifies AptX as a capability. The Sprout claims to support AptX in their literature and uses Cambridge Silicon Radio (CSR) bluetooth receivers (CSR owns the AptX technology). Further up in this post I describe how to “Force AptX” using a software developers tool called “Bluetooth Explorer”. This shouldn’t formally be necessary and in the case of OSX/Mavericks and the Sprout it doesn’t work anyway.

The Bluetooth A2DP profile that is used for streaming audio reserves around 700 Kb/s for itself. Around 512 can be used for payload and most codecs limit themselves to around 350. This isn’t enough for 44.1kHz PCM or even a lossless compression of same. All codecs that work with Bluetooth these days (SBC by default, AptX as an option and occasionally AAC or MP3) are lossy. The maximum bitrate of SBC and AptX are equivalent but naturally CSR makes claims that AptX is a better choice. There is no absolute consensus here. In any case, PCM recordings will have to be encoded on the fly in either SBC or AptX and existing lossy-encoded (MP3 / AAC) music files will need to be transcoded. This last step does a fair bit of violence to the quality. In my experience:

  • 44.1kHz PCM files lose a fair amount of detail in the higher ranges and suffer from occasional "ringing" artifacts introduced by the compression with SBC.
  • High bitrate (320CBR) MP3 files suffer the most from the transcoding to SBC.
  • Low bitrate (128CBR) MP3 goes through the process fairly unscathed.
I would summarize by saying that you should avoid Bluetooth if you want an audiophile experience but if you wanted to connect your phone or tablet to listen to a local radio station or podcast before going to work in the morning it would be more than up to the task.

Can’t speak to AptX but I rarely find magic bullets out there and the physics of Bluetooth limit the choices. I believe AptX is a patented implementation of relatively high bitrate adaptive differencial PCM (ADPCM).


#19
alfa_lover said I agree USB is so much better than Bluetooth.

I am also running Yosemite.


My MacBook Pro running Yosemite only shows SBC when using Bluetooth.

In a high-end audio system I do not see a role for Bluetooth, am I missing something?

USB is ok, but I still prefer CD’s or Vinyl.


#20

I’m using Yosemite, tried everything including bluetooth explorer, removing all existing devices (keyboards/touchpad), unpairing everything from sprout, clearing the bluetooth stack, setting up a vanilla OS X acct, etc etc (also tried on 2 diff machines).

Was never able to get AptX to kick in.

Anyone try an Android phone? They have AptX built in–