I too feel that audio quality over Bluetooth was better a few weeks ago.
There were one or two builds where it got really bad but it's OK now but not as good as it once was.
It may have been the use of GravityBox which I used for two or three nightlies before canning it again but I'm not sure.
I use Omni on a Sony Xperia Z so this is only in regards to this phone.
I'm now sure that the audio quality over bluetooth is worse than it was a few weeks ago.
Today I flashed CM11 to compare BT audio quality and on CM it was so much better (like it was on Omni when I started using it).
On Omni there is almost no bass at all and highs are a bit distorted whereas on CM audio over bluetooth (Xperia Z with Sony SBH20) sounds almost identical to directly plugged in headphones.
I have newly installed yatour box with bluetooth receiver on my car and the sound quality over bluetooth from I9100 with Omni is really bad.
The sound is almost crackling on some quiet places. Sound is perfect if connected to yatour's aux input with cable.
I have to test it with another transmitting device (without Omni) to rule out problems with the bt receiver though.
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