setting gain on DAC with a2dp_sink_and_hfp_example Lyra T

[Tsardoz]

First time using module I tried ADSL playback and the volume was very low from phone even when volume control was maximum.
I compared it to another BT speaker using same driver so volume should be about the same (the comparison was only using VBAT compared with VUSB from Lyra T).
Looking at the code I cannot see anywhere where the gain of the DAC is set.
From the ES8388 datasheet it seems the default gain is -15 dB. No wonder it is quiet!
The defaults for register 39 and 42 (left and right DAC control 17/20) is 0011 1000
I need to change it to 0001 0000 to have 0dB gain.
Has anyone successfully changed these registers and provide code?
If not, once I work it out I will post back but I am surprised there does not appear to be any configuration of this unless I missed it.

[Tsardoz]

PS. Datasheet of power amps is here
http://inder.cn/WJXZ/nsiway/InderNS4150EN.PDF

It is pretty poor - no mention of what the gain is for these amps. It may be that <0dB is required to achive maximum output which can only be determined by testing.