I've been having trouble with the sound quality of with my Motorola Roadster 2. Basically this is a bluetooth In-Car speakerphone that can stream incoming media audio to my FM radio, so I can enjoy listening to my music library in my car that has no 3.5mm jack. I always thought that the sound quality was mediocre due to the FM remodulation, that is, until I connected an iPad to it and played some songs over it. The quality was absolutely better than that of my Android phone. Apple has a different bluetooth stack for their devices obviously, so I've started looking into this. I've used this Stack Exchange answer to find out what codec my Samsung Galaxy S3 was using when streaming to the device. It seems that the Roadster 2 uses the A2DP profile and supports SBC as well as MPEG-1.2 codecs, but the phone chooses the inferior SBC after checking the capabilities for some obscure reason. Some research suggests that SBC is not recommended for music streaming because quality is not ideal, so my guess was to try using the MPEG-1.2 codec instead. However, after some very thorough digging, I cannot, for the love of God, find any configuration to try and force the MPEG-1.2 codec with the Bluedroid Bluetooth Stack that is used with Android 4.2+ . The old BlueZ stack had an option in its configuration file (/system/etc/bluetooth/audio.conf) to enable a different codec, but it doesn't work anymore with the new Bluedroid stack. Is there a similar way to force a different codec than SBC? I'm using Android 5.1 (Cyanogenmod 12.1 to be exact).

Bluetooth's Audio Profile A2DP supports multiple codecs. All devices have to support SBC (subband codec), then they can support additional "optional codecs" like MP3 and AAC, or "non-A2DP" codecs like apt-X. Of course these codecs can't actually be used if the receiver doesn't also support them, in which case both devices fall back to SBC. 1. How do I find out which codecs my hardware/ROM support? 2. How do I find out which codec is currently in use? (Maybe this depends on the track, too, if it passes MP3/AAC files directly without re-encoding, for instance)

I was pleasantly surprised to see that I can pair & connect my Nexus One with **two** identical NoiseHush N550 Bluethooth headsets **simultaneously**. Unfortunately however, only one of them (always the last to be connected) seems to receive actual audio. Is this a known limitation in the Android OS (version 2.2.1)? Or is there a setting or workaround that allows sending audio to both devices simultaneously?

From http://soundexpert.org/news/-/blogs/bluetooth-audio-quality-a2dp , and https://android.stackexchange.com/questions/26410/how-do-i-determine-which-a2dp-codecs-my-phone-supports-is-currently-using , I can see that when I listen to bluetooth audio from my phone to my car, I am getting sbc with these parameters: Middle Quality Joint Stereo Samp Freq 44.1 kHz Bitpool value 35 Resulting Frame length 83 bytes Resulting bit rate 229 kb/s Block length 16 Allocation method = Loudness Subbands 8 Can someone share an equation of how these parameters relate to each other? Does any sbc at 44.1 KHz and bitrate 229 kb/s have to have bitpool = 35 and frame length 83 bytes?

I'd like to be able to send A2DP to my car stereo while at the same time sending phone calls to the speakerphone I have in my car. I haven't bought the stereo adapter yet, since I wanted to find out if this setup would work, otherwise I would just try it. ;) Thanks!

How can I set up my Nexus 4 to receive Hangouts and phone call audio over a Bluetooth A2DP link? Even though my headphones are connected, in-call audio is routed to the earpiece or speaker and there's no option to send it over BT. I've got Creative WP-350 headphones that support both A2DP and HSP but the headset profile audio quality is unusably low, leaving no other option but to disable it in Android BT settings.

Sometimes when I connect my phone to my headset, the Bluetooth device will be listed as: "**Connected ( no media )**" When this happens, it uses the "Phone audio" profile. The "Media audio" profile (A2DP) will also have a checkmark, as if it were connected, but all sound is coming from the phone's speaker (see photo below). If I attempt to uncheck it, it will immediately recheck itself. When it *is* working properly, it will wait two seconds and disconnect. Rebooting the headset, or disconnecting it manually doesn't solve the issue.

In my car I have my old Android phone as the GPS and music player. I was hoping to use it as a receiver for my calls coming to my other phone and any bluetooth devices around it streaming music. Is there a way to do this? I have searched Google thouroughly.

I have a car stereo which supports bluetooth phones, but not A2DP audio playback. I purchased an A2DP adapter. I have easily paired my *HTC Thunderbolt* to the Cicada which pipes audio to the aux jack in the Juke, and plays back. (Sounds great, incidentally.) However, upon connecting to the Cicada, the phone is no longer connected to the Juke for phone calls. Is there a way to tell Android to force send HSP data to the hands-free set, and force all A2DP data to the A2DP adapter? The A2DP tells android it supports HSP and therefore overrides the Juke pairing.

Today I watched this video in below url and I am wondering why Google Nexus 7 and Google Nexus 4 cannot act like this. Unable see the incoming call coming from paired device in Nexus. URL: http://support-us.samsung.com/spstv/detail.jsp?ctg_id=209&sub_ctg_id=&live_id=8 I have updated both the device to Android 4.3. Have I missed any settings or Nexus does not support A2DP? or only Galaxy Player supports this? Thanks Deepak

When I'm playing audio over the A2DP data path to my car, the audio randomly will drop for half a second, then gradually comes back to full volume over perhaps a second of time. Speaking like a programmer, it's almost like something mutes the audio and then slides the volume up in a loop or something. This problem did not occur on Bombaridier and the older Synergy Kernel, however it is happening with the newer kernel on Juggernaut v5, Paradox and SlickMOD, leading me to believe something in the kernel or newer system binaries might be causing it. This behavior happens in Pandora, Amazon MP3 and also the stock Music app. Thinking that maybe a stray notification was the problem, I've tried disabling notifications in all of the apps I know of that notify, I've also tried switching the phone into vibrate and finally into full-silent, but it does not seem to affect the behavior. I have found no likely cause. I wish I was able to log alsa changes; maybe a script running constantly with something like:

while (true)
do cat /proc/alsa/some_alsa_status_entry >> /tmp/alsalog
sleep 1
done

Does anyone else have any ideas as to what this might be? It's really annoying!

I have a stereo Bluetooth headset. When paired and connected, both the Phone and Media profiles are supported. I can hear Google Maps Navigation voice directions in the headset. However, if I uncheck the Media profile (I am using the the media profile to connect to an iPod touch), then the voice directions come out of the speaker. I want them to come over the headset. From this, I assume that the phone wants to send the voice directions to the A2DP if the headset supports it, and to the speaker if the headset does not support A2DP. Is there any way to configure the Phone (Bell's Samsung Galaxy S) so the voice turn-by-turn directions are sent to the HSP (headset) profile (where to audio for cell phones voice calls is directed)? Although I haven't tried it, I assume this problem exists for simple non-media headsets that only support HSP.

Ever since the Gingerbread update, my N1 has been experiencing random audio dropout problems every 5-10 minutes when connected to my car's audio system via Bluetooth. The audio will be streaming normally, then I'll hear a "pop" sound and the volume drops to zero, then immediately fades back in. The whole process lasts about three-quarters of a second, then everything is back to normal until the next dropout. This happens regardless of which audio application I am using. It does not happen when I am listening to the device over headphones or through the internal speaker. It did not happen under Froyo. Has anyone else experienced this? Does anyone have any idea about what might be causing it or how I can fix it?

From one day to another it seems that A2DP stopped working for me. I used it to stream music from my phone to my car's stereo. Everything worked fine until yesterday. I didn't install or upgrade any software as far as I remember. What happens now is that everything _seem_ to work but I don't hear anything. The media player on the phone is running. When I adjust the volume on the phone I see the popping out slider showing 'bluetooth media volume'. Also I can skip tracks using my car's buttons (AVRCP profile) and display track information in my car's display (ACRCP 1.3 supported by Samsung media player on Galaxy SII). I can use the phone, too (handsfree profile), here I can hear everything. I think its a matter with the phone and not with the car since I tried another phone, that works as expected. Unfortunately I don't have another A2DP headset or similar to try with my phone. A already tried to delete the pairing and pair new but it didn't help. Ideas anybody? I use a Galaxy SII running 2.3.4. One more thing I should mention: I don't think that this is the reason but I had an issue with my phone's micro USB port the same day. It was always saying it's getting charged via USB but it wasn't. Also car mode switched on and off sometimes without user interaction. So I removed the battery, tried to clean the micro USB port by blowing in it, waited some hours and after that everything's fine again. But as I said, I don't think that this is related since there's no reason why a defect micro USB port (and it doesn't seem to be defect though) should stop A2DP working. **Update:** Found [this similar problem](http://www.droidforums.net/forum/tech-issues-bug-reports-suggestions/2771-a2dp-streaming-not-working-mazda-cx9-3.html) and will try unpair, remove battery and pair again as suggested tomorrow. Will give an update here.

If i have my phone (thunderbolt cyanogenmod7/2.3) connected to a bluetooth stereo and i hit the play button on the stereo, music, pandora, Subsonic, and Audible all start playing at once. pausing pauses all of them. is there some way of controlling what apps respond to the buttons? is there an app to filter button events?

After moving from Symbian to Android, I noticed an audible* drop in audio quality when listening to music via bluetooth (A2DP ). I woudn't say the quality is *poor*, but bad enough for me to investigate the issue. While it probably is audible all the time in some way, it's not easy to pinpoint - I can only notice the difference in some music passages. Unfortunately it's usually most audible in the passages with most impact, where it also bothers the most. As audio quality issues are notoriously subjective, I did wonder whether I'm just imagining the effect or not. Turns out, I'm not - I haven't done any blind testing or anything, but comparing the same file A2DP streamed from my computer to the one streamed from Android (and for control doing the same comparison with wire-plugged headphones) it's easy to spot the difference. Doing a bit of research into the issue, it seems A2DP can be used to stream audio into bluetooth receiver with multiple different codecs and setting. As far as I've understood the discussions related to this, it looks like this could be either caused because Android is using SBC codec instead of MP3 or because it fails to use high enough bitpool setting . There seem to be multiple reports of this problem around the net. So my question is: **How do I fix the sound quality?** **Is it possible to change A2DP settings to get bluetooth audio quality matching that of Symbian and my laptop?** My Android device is GT-S5570 running 2.2.1. *\* - I don't consider myself an audiophile, and I don't spend money of pro audio gear. This isn't something that's hearable only in perfect conditions at a sound analysis studio - I hear it using the cheapest stereo bluetooth headset I could find (BH-505 at 50€).*

I've been using Google Listen for podcast catching and playing. Seems to work just fine. I'd like to be able to play my podcasts over my Bluetooth headset. Alas, it seems that is only an option for A2DP bluetooth headsets(?) so I'm on a quest. Can anyone offer suggestions? Seems like I have two options (but maybe there are others). 1. Find a podcast catcher/player that will play over a non-A2DP headset 2. Find a way to "fake" the Android into using a bluetooth headset even when not A2DP Anyone have any thoughts or suggestions? [edit] I should mention that I'm running stock 2.1 and have no real desire to root/mod the phone.