iPhone 3.0 A2DP Distortion Using Bluetooth Car Kit

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joshd2012 Author

Level 1

9 points

iPhone 3.0 A2DP Distortion Using Bluetooth Car Kit

I purchased a Kensington Bluetooth Car Kit for my wife (the one with the aux output) so that she could use her iPhone in her car. The was just after the 3.0 software was revealed, so I also purchased a Sony iPod Bluetooth Adapter so that she could pair the iPhone to the car kit for both phone and music. It worked ok, except that the music would get distorted sometime, and sometimes it worked perfectly. I assumed that it was because I was using an adapter, and thought the problem would be resolved once the 3.0 software was released.

So after updating her iPhone yesterday, we ran out to her car and tried it, only to find that there was now always distortion! It paired quickly, and everything seems to work fine. The distortion is most evident on iTunes Plus tracks (not so much on lower quality tracks, though its still there). Is there some setting that needs to be changed in order to get the music to play without distortion? Is this a limitation of the hardware?

Additional info: Calls sound fine, as does internet radio, though they are of noticeably lower quality than the iTunes.

iPhone, iPhone OS 3.0, Kensington Bluetooth Car Adapter

Posted on Jun 18, 2009 6:16 AM

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Answer 1

joshd2012 Author

Level 1

9 points

Jun 19, 2009 8:11 AM in response to joshd2012

Any help? Bump.

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Answer 2

Deofol

Level 1

0 points

Jun 22, 2009 1:59 PM in response to joshd2012

Not really a help, but I have an Eclipse CD3200 head unit that supports A2DP as well, and it sounds awefull. Very distorted especially on highs.

Fairly bummed about it.

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Answer 3

carled

Level 1

0 points

Jun 23, 2009 7:46 AM in response to Deofol

It's worth looking into the encoded volume of the mp3. Many people don't realise that lots of mp3s are encoded at too high a gain level. This leads to distortion issues on playback.

To fix this without re-encoding, there's a nifty utility called mp3gain: http://mp3gain.sourceforge.net/

This writes information to the header that is looked at by the iphone and the volume adjusted accordingly. 95% of my mp3 collection needed adjusting; it's a VERY common problem.

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Answer 4

joshd2012 Author

Level 1

9 points

Jun 24, 2009 8:46 AM in response to carled

Does that include iTunes as well? I have noticed that the iTunes stuff is much more problematic than the older stuff.

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Answer 5

carled

Level 1

0 points

Jun 25, 2009 2:52 AM in response to joshd2012

It might well do. It's just a case of starting up mp3gain, pointing it at the relevant files (itunes stuff is normally in my music/itunes/album name folder) and let it analyse it.

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Answer 6

Haji

Level 1

5 points

Jun 27, 2009 10:39 PM in response to joshd2012

I have an iPhone 3G 16gig. I just bought a Kensington Liquid AUX Bluetooth Car Kit, paired everything up, and tested it out in the garage. The only downside (at that point) was that the included remote only controlled start and stop, not forward and back tracks. Later I tested it on the road and thought my ears were playing tricks on me when I heard the music changing pitch. Once I figured out it wasn't me, I changed tracks and even tried streaming radio and still, pitch up/pitch down, song faster/song slower. I noticed it got markedly worse when I tried to use another program while having the ipod play in the background, which makes me think it is a hardware issue; possibly the processor speed or "RAM" or however iPhones work. I am planning on trying it with my ipod and a bluetooth attachment I have for it to see if the music distorts. If it is the hardware on the phone, looks like apple forgot to mention as a selling point that the faster innards are needed for true A2DP stereo bluetooth! Another part of their brilliant scheme I guess!

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Answer 7

joshd2012 Author

Level 1

9 points

Jun 28, 2009 7:17 AM in response to Haji

I had the same thought, that the A2DP may be too much for the older iPhones to handle - or at least in their current configuration. It might be as simple as optimizing the code to make it work better, but that is something Apple is going to have to answer. The Sony Bluetooth adapter seemed to do a better job than the internal iPhone hardware, which is disappointing since its more of a work-around than anything.

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Answer 8

Jun 28, 2009 9:42 AM in response to joshd2012

I bought 2 Motorola S9 bluetooth headsets a few days before the update, for both my wife's and my iPhone. It has been working GREAT! but I did have the distortion problem a few times. It felt like more of a "drop out" of signal--like the iPhone wasn't keeping up with the bitrate--so I rebooted the iPhone to try to clear it up. It worked every time.

A few days later my wife had the same problem, so I told her to reboot her phone as well. The problem cleared up nicely after reboot for her as well.

It seems that some programs leave orphaned processes and memory running and in use even after closing--email, pandora, many games, etc., which is why so many apps ask you to "reboot after installing." It seems that this effects A2DP Bluetooth (at least on the 3G model) as well.

I'm thinking of grabbing one of those "clean up memory" apps to see if that helps. It should be faster than rebooting. If it works I'll try to post results here.

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Answer 9

t0ffluss

Level 1

0 points

Jun 30, 2009 5:43 AM in response to FL-Howard

Anyone tried the MP3Gain thing mentioned in a previous post? I also have issues with distortion on my Motorola T605 which is integrated into my Renault factory headunit.

Sounds terrible, as if the the volume is too high..

Iphone 3G running 3.0

Message was edited by: t0ffluss

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Answer 10

neonsox

Level 2

214 points

Jun 30, 2009 6:32 AM in response to joshd2012

I'm using a Dual XHD6425 HD/BT setup in my car and I'm noticing the same thing. Call quality is good but the A2DP stream is a bit distorted on the higher notes. I thought maybe it was some sort of interference, but it distorts wherever I place the phone. It would be great if they could fix this via software and save me from having to plug into the AUX to get good quality.

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Answer 11

bilby91

Level 1

35 points

Jun 30, 2009 2:25 PM in response to neonsox

can i use my iphone 2g with a bluetooth car kit?

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Answer 12

Haji

Level 1

5 points

Jun 30, 2009 2:52 PM in response to joshd2012

Alright, so instead of try out my bluetooth adapter for my iPod, I just bought a 3GS. Haha! Everything is working flawlessly now. No distortion whatsoever. Therefore, I conclude that it is a hardware/memory problem.

Unrelated: I get in my car and in a few second it connects, then when I get out of my car, I flip on my new Lubix NC1 bluetooth stereo headphones ($20-30w/shipping on ebay) and it connects to them! I only have to wait a few seconds to continue listening to whatever song/podcast I was listening to! Should be great for the commute and the subsequent walk from the parking lot. Gotta love A2DP!

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Answer 13

joshd2012 Author

Level 1

9 points

Jul 7, 2009 1:18 PM in response to Haji

Anyone else able to confirm? Sounds like you have definitive proof, though, that the 3G just can't handle A2DP and is causing distortion. That's disappointing. I wonder if Apple is aware/able to help?

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Answer 14

Thanar

Level 2

302 points

Jul 7, 2009 2:15 PM in response to joshd2012

I think it is possible that the iPhone 3G is having speed issues when using A3DP, since I guess there's some on-the-fly encoding that needs to be done, prior to sending the audio over to the other bluetooth device. I have noticed distortion and even pauses using me A3DP-capable Jabra BT530 headset, but seem more memory-related or thread-related than CPU, since the only occur when at the beginning of a track.

Regarding mp3gain or so, the app that changes the file's header so as it plays on a lower volume, I don't think it will work, especially with iTunes Plus music, since iTunes plus (and iTunes store music in general actually) is using AAC-encoded audio and not mp3.

Finally, I would like to add that a bit refining to the new bluetooth deamon would take away such distortion, hick-ups and pause issues when listening to audio through A2DP, IMO.

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Answer 15

Jul 15, 2009 2:26 PM in response to joshd2012

I had the same problems with audio distortion as everyone else, but I may have a fix, at least a temporary fix. I have several A2DP devices, Motorla EQ-7 and Sony BTM-30 bluetooth speakers, as well as the following BT headphones- Motorola S805 and a Sony DR-BT50. All devices had the same high frequency distortion problems.

I called Apple to get resolution for this and they said to unpair all devices and reset the Network Settings. Settings> General> Reset> Reset Network Settings. I did this and it clears out saved networks but it magically cleared up the distortion problem.

Problem is, when I started to load in new wifi networks, the distortion came back. I repeated the above procedure, distortion gone.

Hope this helps you, too!

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