[Galaxy Tab S Android Development] :
Essay on bt-audio

This will be a little longer. So for the people, who think some of my posts are too long, this is the abstract: there are no issues with bt-audio, but very little stutter, when 2.4GHz wlan is on heavy use. It seems to me (but I can't proof with meassurement, it's just my impression) that the highr channels are a little bit better to use while bt is used, then the lower channels.

If you hear only garbage, do this:

Power off bt device.

DELETE the bt device from chagallwifi's bt configuration.

Switch off bt on the chagallwifi.

Power off chagallwifi - or do a reboot (NOT! a fast reboot).

Power on both devices.

Repair the bt-device on the chagallwifi.

Listen to Green Day (really great band) ;)

Disclaimer: I'm not an employe of bose, nor do they pay me in any way. (For that matter: I alwys prefered Teufel sound system speakers over the ones from bose.)

The last couple of days I have read many bt-device's specs as well as the a2dp specs from bluetooth.org. This morning I had enough of theorie, so I took my manta, bacon and chagall and went to the mall. Saturn offers me to pair my devices with a sondlink mini II and a soundlink III (the latter is the bigger one).

I was so impressed by the relation between size and sound, tnat I bought a sondlink mini II. I teted with flac (since storage is not really expensive anymore, this is my favorite audio format) files: Baba O'Reiley (The Who), 21 Guns (Green Day) and the duett from Don Carlos and Marpuis de Posa from Verdi's Don Carlos (George Solti; tne digital remastered version of the recording). This three songs played via soundlink mini lI completley blowed my mind. I wouldn't take this device as a neutral studio monitor, but it is just fun for the ears, what bose is doing. The difference to the much larger soundlink III is, that the latter is much louder in the end. Regarding to clearness and transparence of the music the mini is on the same level than the larger one - for my ears even a bit better. So they got me, and I was unable to not buying this device... (compared to the beatspill I could test there also, the bose devices are playing in their own league.)

Playing the files locally on the device with wifi off I can't hear any issues. The same goes for the test with local files and 5GHz wlan on and rsyncing a file (rsync lis a unix tool to sync two directories or files; I used this rom's zip to get usage on wlan. Playing local files with 2.4GHz wlan on gives some skips (aboit one per minute, Iwould say). The same goes if I play the files remote from my bacon (bacon has hotspot on and samba is the fileserver for es-explorer).

BTW: the interference with 2.4GHz is reproducable with bacon and manta.

I was pairing/unpairing all the time. No problems, but the described interferenoce with 2.4GHz wlan. I also tested with audio fx for bt on and off. Regarding the skips it doesn't make any difference (my ears told me, the best sound from the mini II is achieved when audio fx is completely off - it's really a maze, what this small device is making with music!)

On my way back, I used my new device paired with bacon in the car: it clearly outperformed my car hifi (opel astra build in).

At home I reconnected the mini II to chagall, and I could only hear garbage: not music with crackling, but a real mess: I couldn't even have guessed, what title is playing. Totally unusable. I disconnected and reconnected: the same - garbage.

I tried to connect my bacon: error: wrong pin, couldn't pair.

Long story short: I had to switch off the mini II, delete the device from the chagall's bt configuration, switch off bt on the chagall, reboot the chagall, and after switching on bt again and repairing the mini II, I had christal clear sound again. (I didn't need to reboot my bacon, it repairs perfectly, after the power cycle on the mini II.)

Some other details I realized while testing:

At least on flac files the cm music app sounds clearer then google play music. Bacon is a very little bit clearer than chagall, which is better on sound than manta.

When playing youtube videos there is a little lag between lips mobement and sound (very, very little. You can observe in your born language - I couldn't see/hear this lag on an english spoken clip, but on german ones. To realize this lagging you need to be used in seeing, speaking and hearing the language - so I consider this lagging as very small).

The salespersons at Saturn get nervous, if you sit to the floor, get two tablets out of your backpack and start playing with three bt-devices at the same time... ...but it's fun for you. ;) When I started to explain, what I try to do, the salesperson roles eyes. When I asked him which mandatoty a2dp codecs these devices support, he excuses and went away. ;)

The important insights of this day for me so far:

Mini II is a great device. Really.

The 2.4GHz wlan is old, slow and obsoleted by 5GHz. It should go away... ;)

Green Day is a great band.