It's no secret that LG puts a ton of effort into the sound on each smartphone. The original LG V10 came out of no-where with a 32-bit Quad DAC that audiophiles and musicians absolutely loved.
Each year since LG has continued to release great phones with a capable audio experience. And lately, they've paired those with AptX, Dolby, or added things like a BoomBox speaker to the LG G7.
Basically, if audio is important, wait for the LG V40. It'll likely have one or even dual boombox stereo speakers, a Quad-DAC, and a bunch of customization that makes it the best smartphone for audiophiles. The G7 is one of the best-sounding phones I've ever heard.