# Multiple Bluetooth connections



## navidf (Feb 14, 2012)

I have a WiMM one watch module connected to my Gnex on AKOP M3/leankernal. When in my car, the quality of the sound connection to my car's audio via bluetooth drops dramtically. When I disable the WiMM, the quality returns back to normal. The enginners at Wimm have told me that in their testing, this was not due to their module, but rather any multiple connection to the Gnex. Apparently when more than one device is connected through Bluetooth, the sound quality degrades. They attribute that to the Bluetooth stack used in the nexus.They were able to reproduce the problem with connection to other devices than the WiMM.
Anyone else has noticed this?
Any solutions?
Can Bluetooth stack be replaced? Changing from 4.03 to 4.04 ROM changes anything to the Bluetooth stack?
Thanks


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## darkrom (Jul 30, 2011)

Bump for more info!


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## ig88 (Dec 19, 2011)

I have the same problem. When my phone is paired to my car's handsfree and my A2DP aux adapter at the same time, phone calls sound garbled. Either device sounds great independently. I have duplicated the same behavior using two bluetooth headsets (one set for media the other set for phone audio). I have tried all of the radios including 4.04 and used stock, franco, and faux kernels. So far I have also edited audio.conf (Master=True & Maxconnections=3), with no effect. I recall having a similar issue when running CM7 on my HTC Incredible. The belief in that thread was the noise was due to a difference between the open source Bluetooth stack and HTCs Bluetooth stack. Is there any ROM or Kernel for the Nexus that currently uses an alternate bluetooth stack? Have any kitchens been released that allow changing the Bluetooth stack? This problem is really frustrating because I usually stream podcasts whenever I drive. Other than this issue, I love the phone.


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## johnwc723 (Jan 15, 2012)

Bump! I just ordered an A2DP adapter for my car and planned to have handsfree connected at the same time. It looks like this might not work too well you guys are saying?

John


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## ig88 (Dec 19, 2011)

johnwc723, that's exactly the situation we are in. Once there are multiple bluetooth connections, the call quality is terrible. Once in a call, even if I unplug my A2DP the call quality does not improve unless you hang up and dial again. I have a usb port available, but my car can't see MTP drives. Does anyone know of a setting to increase the bitpool?


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## navidf (Feb 14, 2012)

Doesn't anyone with some know how has any insights into this possible defect? Any developers?


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## whezzel (Jun 25, 2011)

not 100% sure on this but my guess would be that when u have one connection all the Bluetooth bandwidth is for that one device that's connected but like any network when u connect more then one device the bandwidth is split between all the devices. So the sound quality would be less because of the less bandwidth. Don't quote me on this its just my thoughts

Sent from my Galaxy Nexus using RootzWiki


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## navidf (Feb 14, 2012)

It seems if I connect to the car first and then turn on the Bluetooth of the other device, then the car audio's sound is better (still not as good as single connection, but tolerable).


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## ig88 (Dec 19, 2011)

Update - I experimented with a couple of additional devices, and the multiple connections problem with my Nexus is limited to A2DP only devices.
I am now using a Garmin BlueTrip with "phone audio" deselected in bluetooth options. As long as the additional bluetooth device is handsfree profile capable, the A2DP functions perfectly, calls are clear, and the device reconnects after a power cycle consistently. I'm glad this appears to be a software issue and not something we will have to live with for the life of the phone. I'm sure a future update will correct this issue.


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## GorillaTheHutt (Jul 13, 2011)

ig88 said:


> Update - I experimented with a couple of additional devices, and the multiple connections problem with my Nexus is limited to A2DP only devices.
> I am now using a Garmin BlueTrip with "phone audio" deselected in bluetooth options. As long as the additional bluetooth device is handsfree profile capable, the A2DP functions perfectly, calls are clear, and the device reconnects after a power cycle consistently. I'm glad this appears to be a software issue and not something we will have to live with for the life of the phone. I'm sure a future update will correct this issue.


ig88 - i noticed in your post here: http://androidforums...tml#post4182117 that you said the Garmin didn't actually work. i assume since that is a later post, you found even A2DP devices that support HFP don't fix the problem?

also, since this seems to be a software issue, there is a google code bug here: http://code.google.c...detail?id=29564


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