https://www.techradar.com/news/a-super-loud-boombox-speaker-is-the-latest-lg-g7-thinq-feature-to-get-confirmed

LG seems to be enjoying the build-up to the arrival of the LG G7 ThinQ, which gets its official unveiling on May 2. The latest feature to be teased by the company is the phone's previously rumored Boombox Speaker, apparently ramping up the volume by 6dB and doubling the bass output from anything that's been heard before (on an LG phone at least).

In fact LG is claiming you can crank up the volume up to ten times higher than a normal smartphone, because of the way it uses space inside the handset as a resonance chamber. Putting the phone on a solid surface amplifies the bass even further, apparently.