
As I understand it, there are a lot of new DAPs and music-enabled mobile phones that support
A2DP - a technology that allows devices to transmit stereo audio to Bluetooth headphones. It's all the rage with the kids these days, and many fans of cutting cables wherever possible were a bit disappointed when the A2DP acronym didn't make the iPhone's feature list. Thanks to a tip from TUAW reader Earle Davies though, the iPhone apparently does seem to support sending any audio - including music and the audio tracks from your videos - to a Bluetooth headset that isn't even enabled with A2DP - but it aint pretty.
To tinker with this, you of course need to have a Bluetooth headset paired with your iPhone. I personally have an older HS-850, one of the first Motorola models with a microphone that flipped open to toggle the headset on and off. After you've switched your headset on and it's shaken hands with your iPhone, go into the Visual Voicemail screen and tap the Audio button in the upper right (which is otherwise a Speaker button when your headset isn't on and communicating with your phone). You'll receive an audio selection dialog much like the in-call dialog that allows you to chose where to send the iPhone's audio. As you might guess, select the Headset option, then switch over to the iPod and begin playing music or a video. This, unfortunately, is why I had to include 'kinda' in this post's headline - while the iPhone sends audio to both Earle's Motorola H700 headset and my HS-850, it still plays audio though the iPhone's speakers as well. It's a bizarre quirk I can't seem to figure out how to stop, which makes me think this is either an unfinished feature or, perhaps more likely, simply a side effect of some of the iPhone's functionality.
Whether you can use this trick to get the iPhone to send stereo audio to a true set of Bluetooth headphones I couldn't tell you, because I own no such headphones. If you readers tinker with this more and help uncover more of what's going on here, please sound off in the comments.

Reader Comments (Page 1 of 2)
Christopher Price said 7:44AM on 8-10-2007
iPhone will not pair with A2DP headphones currently. I will say though that there is no technical reason that iPhone (and almost every Mac) cannot do A2DP... except for the "technical" fact that Apple hasn't perfected their own A2DP headset yet.
Haven't been able to test with a Bluetooth 2.0 headset, as my iPhone is on GoPhone Pay As You Go (and thus, no Visual Voicemail).
- Christopher Price
http://www.phonenews.com
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Ryan said 8:56AM on 8-10-2007
"I will say though that there is no technical reason that iPhone (and almost every Mac) cannot do A2DP"
Except for the fact that the iPhone's BlueCore4-ROM bluetooth chip set does not physically support it. That seems like a bit of a barrier to me.
http://www.eetimes.com/showArticle.jhtml?articleID=200001811
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Jim Wolsiefer said 10:39AM on 8-10-2007
Odd, last week I had my iPhone plugged into a Dice iPod adaptor in my Lexus -- the iPhone was paired with the car’s Bluetooth at the time, and it was playing music via the Dice unit on the car’s audio system. I was finishing up a call on the iPhone – the music is interrupted as a Bluetooth call mutes any of the car’s audio system inputs – I “hung-up” the call and the music from the iPhone resumed.
Now comes the odd part – I parked the car and unplugged the iPhone before turning the car off and the music stopped playing for a moment and then started again! Via what I presumed was the Bluetooth link… I haven’t tried to recreate this quirk since – but I will now. Makes me think I might have wasted the bucks for the Dice unit and the install!
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Christopher Price said 9:34AM on 8-10-2007
I'm not sure where you're getting the notion that BlueCore4 can't do A2DP. If you're trying to say that the ROM on the BlueCore4 is dumbed-down to restrict A2DP... I find that highly unlikely. The last Mac to have A2DP hardware-restricted was running BlueCore2 I believe. BlueCore3 did have a Multimedia branch (for A2DP), but that appears to have been unified into the BlueCore4 line.
Second, if the BlueCore 4-Audio ROM was in fact not enabled to run A2DP, that's necessarily a technical barrier either. Apple has updated Bluetooth firmwares several times in the past, iPhone is really no different from a Mac in that regard.
I'd love to see some technical documentation that shows that Apple's specific BlueCore implementation makes it not capable of A2DP... but I haven't seen any yet.
- Christopher Price
http://www.phonenews.com
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motech said 9:45AM on 8-10-2007
actually,
ive been doing a variation of this from a few weeks ago . .
my audi has bluetooth - so what i do is call 611 or any number really,
once connected, i press the hold button on the iphone, then play music from the ipod and it plays through speakers in my car and speakers only.
problems:
only comes out in 2 speakers (i think)
sounds muffled
as soon as the phone call ends, so does your music.
anyway . . . still interesting
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Mystic said 10:34AM on 8-10-2007
I would be happy if I could listen to the iPod audio in mono over BT. I just find it easier carrying a BT headset with me than wired headphones.
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Ron reen said 11:49AM on 8-10-2007
This works with Apples bluetooth headset
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Joe Arroyo said 1:03PM on 8-10-2007
I use the original Palm Treo bluetooth headset. Once I'm on a call, I can start a track on the iPhone and the music plays somewhat muffled at the same time in the background. The coolest thing is that the person I am calling also can hear the music sometimes! Not the best audio quality, but good for sharing a track w/buddies.
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David Chartier said 12:14PM on 8-10-2007
#8: does audio still come out if the iPhone's built in speakers when using Apple's headset?
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Ron reen said 12:41PM on 8-10-2007
#9 Yes.
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andrez said 12:55PM on 8-10-2007
I tried this on my stereo headset and the quality was better than when I used my mac. Makes me think that this might be a future feature. Although i dont know anything about the hardware limitations. I waited for a2dp for my mac for years, so i have no hope here either.
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gshephg said 3:20PM on 8-10-2007
I duplicated this on my iPhone + Apple BT Headset.
1. Start your music playing
2. Go to phone app, select Voicemail
3. Tap Audio button in upper right
4. Select iPhone Bluetooth Headset (or BT device of your choice)
Sound quality on the Apple headset is surprisingly good, though limited by BT Audio bandwidth. Might be OK for listening to podcasts and audio books.
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Frank said 4:18PM on 8-10-2007
boo -- doesn't work with my jawbone. : (
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larry Friedman said 4:28PM on 8-10-2007
@14. Works with my Jawbone
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Collin Ruffenach said 4:49PM on 8-10-2007
I sent in this tip the day the iPhone came out. Works with the Jawbone too. You can also be currently on a call and start the music and it will playin the call over to the bluetooth headset as well.
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Benjamin Smith said 10:41PM on 8-10-2007
I live in Germany. Anybody knows whether the software here http://www.dvdtoiphone.net/unlock-iphone.html can unlock iPhone for using as an iPod so that I can sync music to my iPhone?
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az_runner said 1:07AM on 8-11-2007
FYI: The CSR BlueCore4-ROM does support A2DP and AVRCP, which are both required to have a truly great Bluetooth Stereo Solution.
If you look at the Press release for the BC4 launch
http://www.csr.com/pr/pr172.htm
It states that it's designed for being able to handle Bluetooth stereo.
Also, check out the PDF found here:
http://www.csrsupport.com/document.php?did=2302
The data sheet states that it is designed for MP3 Players. The most common use of Bluetooth in an MP3 player is Bluetooth Stereo.
So hardware wise, it is capable.
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Johnny said 1:01PM on 8-14-2007
I have a Plantronics 590, it works with both headphones.... but i still can't turn off the speaker on my phone.
Anyone know how?
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Joseph said 3:12AM on 8-11-2007
works with my jawbone too :-)
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Tyler said 4:17AM on 8-11-2007
I was extremely upset when I found out my new iPhone and my Motorola S9 stereo headset would only do voice calls and not A2DP. I bought the Oakley icombi for $50 and solved that problem. Search Youtube for "iPhone A2DP" for a working video. Works great!!!! Shame on Apple though, those WM5 and WM6 fanboys are loving the fact we have to "hack" at this topic.
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