I have the V10 and can vouch for that device(big brother to the V20). Originally when the V10 was released the DAC was only working with the stock music app. Later on however, LG released an update and the DAC now works with all 3rd party music apps including streaming like Spotify. I was also going to recommend an HTC 10 to you, but I think the screen size being 5.2 would not be enough. Honestly the V10 blows me away, so I'm sure the V20 would be a great option. My device before the V10 was an HTC M8 and that had great audio. Its amazing how much of a steal the V10 can be right now in the used marketplace. I sometimes think of using it as a DAP only. If you want to save some cash, you might consider the V10.
on which device are you talking about?