Sound playback over bluetooth lags

I followed the instructions on Arch Linux Wiki and managed to set up sound playback thorugh bluetooth. However, there is a serious lag when using A2DP profile. No problems when using the headset profile except for unacceptable sound quality. When the profile is set from headset to A2DP there is no lag for a while but it'll kick in sooner or later. What could I do to solve the bluetooth A2DP playback latency problem?