Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Krevnik

macrumors 601
Sep 8, 2003
4,100
1,309
The main reason why Bluetooth audio will never suit for audiophiles is the continous re-encoding.
When you listen to wired headphones on your iPhone, you listen to music, that was encoded once by the music label or Apple itself in one of their data centers. iPhone decodes it and plays it out to the headphone jack. If the music comes from CD, the general mastering for 44.100 Hz occours in the studio. The next quality-decreasing step is iTunes encoding it at maybe 256 kbit/s AAC. iPhone plays it as above. You see: one encoding, one decoding. Everything fine.
When you decide to buy awesome bluetooth A2DP-headphones, here comes what iPhones does with the audio: instead of taking the AAC or MP3-file and sending its still encoded bitstream to the headphones for decoding, it decodes the file as descibed above and re-encodes it with the crappy sbc-codec. This is the only codec required to call a device "A2DP-ready". So even if the headphones and coming iPhones would support Apt-X, it'd still be en-de-en-de-coding of music.
Btw there are plenty of low price phones, which support direct transmission...

iOS does support sending AAC as an optional codec over A2DP, although I have yet to see anything else support AAC as an optional codec, just Apt-X.
 

GadgetGuy1981

macrumors newbie
May 6, 2012
9
0
iOS does support sending AAC as an optional codec over A2DP, although I have yet to see anything else support AAC as an optional codec, just Apt-X.

Shameless product plug here - Actually, the Harman Kardon BT headset supports both AptX and AAC, so the iPad and Mac experience is pretty consistent - That, and the BTs retail for only US$250, compared to most of the competition ringing in around $400.
 

dty1

macrumors newbie
Jan 5, 2013
1
0
Logitech UE9000 BlueTooth and Wired headphones with apt-X

Ultimate ears 9000. They are sold at apple stores. Work great

I also use the UE9000 headphones with my Galaxy Note II - both support apt-X and sound awesome. I also use the UE Boombox that also has apt-X support. I use the Sennheiser BTD 500 USB dongle (with apt-X support) for my computer so the UE9000's work superbly with it as well.

I just need an apt-X dongle for my car audio as it only supports A2DP and does not sound nearly as good. I currently connect my Note II to the AUX port on the car audio for best quality.
 

Menel

Suspended
Aug 4, 2011
6,351
1,356
The main reason why Bluetooth audio will never suit for audiophiles is the continous re-encoding.
When you listen to wired headphones on your iPhone, you listen to music, that was encoded once by the music label or Apple itself in one of their data centers. iPhone decodes it and plays it out to the headphone jack. If the music comes from CD, the general mastering for 44.100 Hz occours in the studio. The next quality-decreasing step is iTunes encoding it at maybe 256 kbit/s AAC. iPhone plays it as above. You see: one encoding, one decoding. Everything fine.
When you decide to buy awesome bluetooth A2DP-headphones, here comes what iPhones does with the audio: instead of taking the AAC or MP3-file and sending its still encoded bitstream to the headphones for decoding, it decodes the file as descibed above and re-encodes it with the crappy sbc-codec. This is the only codec required to call a device "A2DP-ready". So even if the headphones and coming iPhones would support Apt-X, it'd still be en-de-en-de-coding of music.
Btw there are plenty of low price phones, which support direct transmission...

Source?

A2DP requires SBC codec fallback support... But also supports MP3, and AAC. It could stream natively.

----------

iOS does support sending AAC as an optional codec over A2DP, although I have yet to see anything else support AAC as an optional codec, just Apt-X.
How do you know?

E.g. my little Ericsson MW600 I use at work doesn't really have any clear specs. These have some fuzz, I suspect it has cheap audio output components.

The Pioneer 8400BH headunit I have in my old truck, supports BT3.0 and AAC specifically. Does iOS auto detect and send it AAC? This thing pulling bluetooth audio comes through loud and crystal clear with no sign of crushing lows or highs.

I suspect it's as usual with Apple... it just works and we don't know details.
 

Krevnik

macrumors 601
Sep 8, 2003
4,100
1,309
How do you know?

A mix of things:

1) The BT specs themselves for A2DP specify that the only mandatory codec is SBC. MP3, AAC and ATRAC are also specified in A2DP, but are optional. Apt-X is not in the A2DP spec at all (but A2DP supports custom codecs).

2) Apple's developer docs for iOS 6 actually explicitly state which codecs iOS supports. There's a section of the docs outlining all the bluetooth bits and pieces they support, and what sub-features of those various profiles.

3) Having bluetooth debugging on my phone where I can see the handshakes happening (I captured logs for Apple on a BT bug a while back, and the BT debugging is still useful, so I left it installed).

E.g. my little Ericsson MW600 I use at work doesn't really have any clear specs. These have some fuzz, I suspect it has cheap audio output components.

The Pioneer 8400BH headunit I have in my old truck, supports BT3.0 and AAC specifically. Does iOS auto detect and send it AAC? This thing pulling bluetooth audio comes through loud and crystal clear with no sign of crushing lows or highs.

I suspect it's as usual with Apple... it just works and we don't know details.

The whole thing is actually baked into A2DP. Each device can be a source or sink. During the BT handshake the source queries what codecs the sink supports. The source then can select the codec it wants out of that selection to encode media sent. The stream headers include information on the codec, and the sink can just read the headers to know which decoder to use on the stream. But considering iOS only supports SBC and AAC, and anything is better than SBC, it's very likely to pick AAC whenever available.

The 8400BH is a pretty new unit, and wasn't something I was aware of at the time I wrote my original post (back in November). I'm not seeing anything on it that says it supports AAC over bluetooth though. Not many manufacturers say what they support. An example is that my Sony head unit (XAV-601BT) can play back AAC on a USB stick, but it only accepts MP3/SBC over bluetooth.

Without Pioneer saying "Yes, we support AAC over bluetooth" or having BT diagnostic logs that show the head unit reporting AAC support, it's hard to say. A lot of the issues with crushed highs over SBC tends to be with devices selecting the wrong bitrate. iOS had that issue early on, and somewhere along the line switched to always sending the maximum SBC bitrate allowed by the device.
 

Menel

Suspended
Aug 4, 2011
6,351
1,356
A mix of things:

1) The BT specs themselves for A2DP specify that the only mandatory codec is SBC. MP3, AAC and ATRAC are also specified in A2DP, but are optional. Apt-X is not in the A2DP spec at all (but A2DP supports custom codecs).

2) Apple's developer docs for iOS 6 actually explicitly state which codecs iOS supports. There's a section of the docs outlining all the bluetooth bits and pieces they support, and what sub-features of those various profiles.

3) Having bluetooth debugging on my phone where I can see the handshakes happening (I captured logs for Apple on a BT bug a while back, and the BT debugging is still useful, so I left it installed).



The whole thing is actually baked into A2DP. Each device can be a source or sink. During the BT handshake the source queries what codecs the sink supports. The source then can select the codec it wants out of that selection to encode media sent. The stream headers include information on the codec, and the sink can just read the headers to know which decoder to use on the stream. But considering iOS only supports SBC and AAC, and anything is better than SBC, it's very likely to pick AAC whenever available.

The 8400BH is a pretty new unit, and wasn't something I was aware of at the time I wrote my original post (back in November). I'm not seeing anything on it that says it supports AAC over bluetooth though. Not many manufacturers say what they support. An example is that my Sony head unit (XAV-601BT) can play back AAC on a USB stick, but it only accepts MP3/SBC over bluetooth.

Without Pioneer saying "Yes, we support AAC over bluetooth" or having BT diagnostic logs that show the head unit reporting AAC support, it's hard to say. A lot of the issues with crushed highs over SBC tends to be with devices selecting the wrong bitrate. iOS had that issue early on, and somewhere along the line switched to always sending the maximum SBC bitrate allowed by the device.
Informative!
 

Menel

Suspended
Aug 4, 2011
6,351
1,356
A mix of things:

1) The BT specs themselves for A2DP specify that the only mandatory codec is SBC. MP3, AAC and ATRAC are also specified in A2DP, but are optional. Apt-X is not in the A2DP spec at all (but A2DP supports custom codecs).

2) Apple's developer docs for iOS 6 actually explicitly state which codecs iOS supports. There's a section of the docs outlining all the bluetooth bits and pieces they support, and what sub-features of those various profiles.

3) Having bluetooth debugging on my phone where I can see the handshakes happening (I captured logs for Apple on a BT bug a while back, and the BT debugging is still useful, so I left it installed).



The whole thing is actually baked into A2DP. Each device can be a source or sink. During the BT handshake the source queries what codecs the sink supports. The source then can select the codec it wants out of that selection to encode media sent. The stream headers include information on the codec, and the sink can just read the headers to know which decoder to use on the stream. But considering iOS only supports SBC and AAC, and anything is better than SBC, it's very likely to pick AAC whenever available.

The 8400BH is a pretty new unit, and wasn't something I was aware of at the time I wrote my original post (back in November). I'm not seeing anything on it that says it supports AAC over bluetooth though. Not many manufacturers say what they support. An example is that my Sony head unit (XAV-601BT) can play back AAC on a USB stick, but it only accepts MP3/SBC over bluetooth.

Without Pioneer saying "Yes, we support AAC over bluetooth" or having BT diagnostic logs that show the head unit reporting AAC support, it's hard to say. A lot of the issues with crushed highs over SBC tends to be with devices selecting the wrong bitrate. iOS had that issue early on, and somewhere along the line switched to always sending the maximum SBC bitrate allowed by the device.
Can you further clarify on examining logs.

I have AppleiPhoneConfigurator and can capture the likes of:
Apr 15 11:03:08 Adams-iPhone SpringBoard[67] <Warning>: BTM: attempting to connect to service 0x00000010 on device "MW600" 5C:B5:24:61:17:A9
Apr 15 11:03:08 Adams-iPhone wifid[14] <Error>: WiFi:[387730988.683056]: WiFi unquiescing requested by "locationd"
Apr 15 11:03:08 Adams-iPhone SpringBoard[67] <Warning>: BTM: connection to service 0x00000010 on device "MW600" 5C:B5:24:61:17:A9 succeeded
Apr 15 11:03:08 Adams-iPhone SpringBoard[67] <Warning>: BTM: attempting to connect to service 0x00000008 on device "MW600" 5C:B5:24:61:17:A9
Apr 15 11:03:08 Adams-iPhone wifid[14] <Error>: WiFi:[387730988.716296]: WiFi unquiescing requested by "locationd"
Apr 15 11:03:08 Adams-iPhone SpringBoard[67] <Warning>: BTM: connection to service 0x00000008 on device "MW600" 5C:B5:24:61:17:A9 succeeded
Apr 15 11:03:08 Adams-iPhone mediaserverd[38] <Warning>: 11:03:08.789 <AudioControl> audio device's sample rate is 0; forcing to 44100
etc. But doesn't seem useful.

I have the profile for Bluetooth Debugging from here, but I can't determine how to access the logs
http://www.cultofmac.com/152120/how-to-enable-hidden-debug-settings-on-the-iphone-ios-tips/

I still assume my Sony MW600 uses basic SBC.
My Pioneer Receiver uses direct MP3/AAC, as the quality is very good. Still be nice to confirm.

Sony lists codecs specifically. http://store.sony.com/webapp/wcs/st...&productId=8198552921666372151#specifications
Bluetooth Audio Feature
Audio Codec : SBC/MP3

I assume what would happen, is Sony+iPhone authenticate, see MP3 compatibility. And iPhone transcodes on the fly from AAC to MP3. Does not seem as power efficient as not reprocessing lossy->lossy.
 

Krevnik

macrumors 601
Sep 8, 2003
4,100
1,309
Can you further clarify on examining logs.

I have AppleiPhoneConfigurator and can capture the likes of:
etc. But doesn't seem useful.

The debugging profile allows you to enable and capture more than just the console logs, which you posted. The profile includes data that is much more comprehensive.

I have the profile for Bluetooth Debugging from here, but I can't determine how to access the logs
http://www.cultofmac.com/152120/how-to-enable-hidden-debug-settings-on-the-iphone-ios-tips/

That link tells you how to access them. You might want to read the whole article. And if you do grab a log, I'd be curious to see a log for the Pioneer HU. The diagnostic logs tend to spew lots of technical data that you need the spec to sort out.

I still assume my Sony MW600 uses basic SBC.
My Pioneer Receiver uses direct MP3/AAC, as the quality is very good. Still be nice to confirm.

Sony lists codecs specifically. http://store.sony.com/webapp/wcs/st...&productId=8198552921666372151#specifications


I assume what would happen, is Sony+iPhone authenticate, see MP3 compatibility. And iPhone transcodes on the fly from AAC to MP3. Does not seem as power efficient as not reprocessing lossy->lossy.

Your assumptions are not correct in this case. iOS doesn't support MP3 as output, period. SBC and AAC only, and that's documented by Apple themselves for developers. The reason is that real time encoding of MP3 and AAC just isn't feasible in low power devices without hardware assist. iOS devices have that assist for MPEG-4, and thus AAC.

And I wouldn't assume AAC is being used just because it sounds "good". As I've pointed out already, iOS outputs SBC at the max bitrate allowed. In this mode it is quite hard for me to hear the difference when comparing it to being hooked up over USB. And any difference is fairly insubstantial, more on the edge of hearing than anything describable. So it's very possible that SBC is being used, even if you think it isn't. Hard data is really required.
 

Menel

Suspended
Aug 4, 2011
6,351
1,356
That link tells you how to access them. You might want to read the whole article. And if you do grab a log, I'd be curious to see a log for the Pioneer HU. The diagnostic logs tend to spew lots of technical data that you need the spec to sort out.
I have red.

It says to sync with itunes, then use xcode.

I don't sync with iTunes. It screws things up when I do that, it wants to wipe apps and data. My phone has never been cable synced, iTunes Match, iCloud, and built in App Store has made cabled syncing unnecessary and cumbersome.

Trying to find other ways. ifunbox and iExplorer to see if I could find logs within device.
 

jasonlin

macrumors newbie
Oct 21, 2013
2
0
Shameless product plug here - Actually, the Harman Kardon BT headset supports both AptX and AAC, so the iPad and Mac experience is pretty consistent - That, and the BTs retail for only US$250, compared to most of the competition ringing in around $400.

Search amazon.com for "aptX AAC headphones", you'll see a couple models under $150 with free shipping. I am getting a pair of VOXOA, which discounted $20 at checkout. :D
 

Ronnoco

macrumors 68030
Oct 16, 2007
2,568
522
United States of America
Can anyone say if MM450-X support AAC or do they use SBC?

I have the MM500-X and it says SBC and A2DP apt-x only. Oddly, my Beats Wireless say they support SBC, AAC and apt-x...:confused:
I have a nice little Jaybird apt-x adapter that works great for my iDevices (although I do not use the Senns much for the iPhone or iPad, once in a while with the apt-x dongle), and my MacBook Air has apt-x enabled (and says so when connected to either my Beats Wireless or MM500-X or my FoxL v2 Platinum) and sounds distinctively better (and for some reason louder) than using SBC. I use the MM500-X mainly with my MBA and my Sony TV (with the Jaybird apt-x adapter).
Although the Beats Wireless say they are AAC, they only seem to pair with my MBA with apt-x.
 
Last edited:

andreiru

macrumors 6502
Apr 18, 2008
404
142
Kurgan, RF
Indeed, the 450-x connect with SBC over A2DP where Apt-x isn't an option such as with iOS. Does anyone know if iOS 8 beta supports Apt-x in any form?
 

Ronnoco

macrumors 68030
Oct 16, 2007
2,568
522
United States of America
Indeed, the 450-x connect with SBC over A2DP where Apt-x isn't an option such as with iOS. Does anyone know if iOS 8 beta supports Apt-x in any form?

So far, I've heard nothing to think it will. Right now it seems the only option is to use an apt-x dongle like the Jaybird or the one from Sennheiser (there are others as well). I use the Jaybird with my iPad Air and iPhone 5 and it does make a difference over SBC, however it will be better if someone comes out with a lightening adapter for the dongle as opposed to connecting thru the headphone Jack.
 

HLxDrummer

macrumors newbie
Apr 25, 2014
14
0
Just an idea - why not use wired headphones? Cheap, no lag, high quality. If you are using them to play games I am assuming you are within cord's length of the device?
 

Ronnoco

macrumors 68030
Oct 16, 2007
2,568
522
United States of America
Indeed, the 450-x connect with SBC over A2DP where Apt-x isn't an option such as with iOS. Does anyone know if iOS 8 beta supports Apt-x in any form?

From what I've read (mostly techie and headphone forums) nobody seems to think iOS8 will support apt-x, HOWEVER, THIS THING is AWESOME. I use it with a lightening to 30pin adapter (this device is tiny and hardly adds any size to the lightening adapter) and it works perfectly. I'd been using a Jaybird apt-x dongle out of the crappy iPhone 5 headphone jack and it worked ok, but going out of the 30pin with the Kokkia, the sound is SO much better using my Sennheiser MM500-X (or even to my Beats Wireless). It is a noticeable difference. You can tell it is transmitting apt-x when the device's blue LED blinks twice instead of once (SBC) although I can tell even without seeing the LED, it is THAT obvious.


Excellent little piece of kit while we wait for Apple to bring apt-x to iOS. :) (amazon has it for a pretty good price and free two day shipping if you are a Prime member)...Highly recommended for those with apt-x devices (works nicely with my FoxL v.2 Platinum bluetooth speaker as well).
 
Last edited:

andreiru

macrumors 6502
Apr 18, 2008
404
142
Kurgan, RF
From what I've read (mostly techie forums) nobody seems to think iOS8 will support apt-x, HOWEVER, THIS THING is AWESOME. I use it with a lightening to 30pin adapter (this device is tiny and hardly adds any size to the lightening adapter) and it works perfectly. I'd been using a Jaybird apt-x dongle out of the crappy iPhone 5 headphone jack and it worked ok, but going out of the 30pin with the Kokkia, the sound is SO much better using my Sennheiser MM500-x (or even to my Beats Wireless). It is a noticeable difference. You can tell it is transmitting apt-x when the device's blue LED blinks twice instead of once (SBC) although I can tell even without seeing the LED, it is THAT obvious.


Excellent little piece of kit while we wait for Apple to bring apt-x to iOS. :) (amazon has it for a pretty good price and free two day shipping if you are a Prime member)...Highly recommended for those with apt-x devices (works nicely with my FoxL v.2 Platinum bluetooth speaker as well).

That's exactly what I could do with except that I've got a nine pin ipad.
 

andreiru

macrumors 6502
Apr 18, 2008
404
142
Kurgan, RF
doesn't the lightening adapter work with your iPad? The Kokkia plugs directly into the lightening adapter.

That adapter is 30 pin and my ipad is 9 pin so they're incompatible. Furthermore the 30 to 9 pin adapters seem to be incapable of transmitting audio on the ipad (so a 30 to 9 to apt-x isn't possible & would be too much even if it did work). There seen to be no 9 pin to apt x adapters. Apple's 9 to 30 adapter seems to transmit audio but a) it's expensive and b) too many adapters.
 

Ronnoco

macrumors 68030
Oct 16, 2007
2,568
522
United States of America
That adapter is 30 pin and my ipad is 9 pin so they're incompatible. Furthermore the 30 to 9 pin adapters seem to be incapable of transmitting audio on the ipad (so a 30 to 9 to apt-x isn't possible & would be too much even if it did work). There seen to be no 9 pin to apt x adapters. Apple's 9 to 30 adapter seems to transmit audio but a) it's expensive and b) too many adapters.

Wait, what? The adapter is 30pin to 9pin, right? It works perfectly on my iPad air. :confused:
I can understand if you don't like the adapters (like I said, the Kokkia apt-x adapter is about a 3rd the size of the Lightening to 30pin adapter and adds very little in terms of size to this setup) or don't want to pay the price, but the fact that you have a "9 pin iPad" has nothing to do with whether this solution actually will work to produce quality apt-x sound from your iPad. It works with a "9 pin iPad".
 
Last edited:

andreiru

macrumors 6502
Apr 18, 2008
404
142
Kurgan, RF
Wait, what? The adapter is 30pin to 9pin, right? It works perfectly on my iPad air. :confused:
I can understand if you don't like the adapters (like I said, the Kokkia apt-x adapter is about a 3rd the size of the Lightening to 30pin adapter and adds very little in terns of size to this setup) or don't want to pay the price, but the fact that you have a "9 pin iPad" has nothing to do with whether this solution actually will work to produce quality apt-x sound from your iPad. It works with a "9 pin iPad".

Wait, what? The adapter is 30pin to 9pin, right? It works perfectly on my iPad air. :confused:
I can understand if you don't like the adapters (like I said, the Kokkia apt-x adapter is about a 3rd the size of the Lightening to 30pin adapter and adds very little in terns of size to this setup) or don't want to pay the price, but the fact that you have a "9 pin iPad" has nothing to do with whether this solution actually will work to produce quality apt-x sound from your iPad. It works with a "9 pin iPad".

Granted, Apple's adapter might work, albeit at a cost. It's a mystery why after market ones don't work with the iPad properly. But then yes, it's two adapters piled up - kind of defeats the point of portability in the first place. So much trouble for what should already work natively... I do hear a difference between cabled mm450-x to iPad vs wireless. I'd consider a small 9 pin to Apt-x if there were any. I guess your suggestion is the next best thing so thanks for the lead. It sounds like you're into music as well so I'll consider it again based on your recommendation once my headphones are back from repair from Sennheiser (been there for 2 months now). Any chance you could share a photo of the setup so that I can get an idea of the dimensions?
 

Ronnoco

macrumors 68030
Oct 16, 2007
2,568
522
United States of America
Here are a few photos of the Kokkia next to the Apple adapter and then connected to my iPhone 5:

imagejpg1.jpg
imagejpg2.jpg
imagejpg3.jpg


It is, as far as I know, the best (and most direct) way to transmit apt-x from an iOS device to an apt-x headphone or speaker.
As I said earlier, it works perfectly, and CLEARLY sounds better than using any apt-x headphone dongle. Being able to bypass the crappy iPhone/iPad headphone circuitry and going direct out of the lightening port makes a huge difference.
I get that some people don't want to have to use an adapter or won't like having to use the Apple 30pin to Lightening along with the (tiny) Kokkia apt-x adapter, but it works, sounds amazing and is really easy to use (with the iPhone, the whole thing fits easily in my pocket).
Anyway, just an option for you that actually DOES WORK with the 9pin iPad without having to use the horrid Apple headphone circuitry.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.