Dirac is a Swedish audio firm that specializes in sound optimization and they have partnered with manufacturers like BMW, Bentley, Rolls Royce and a lot more.
Dirac Power Sound is a technology that makes even the tiniest speakers give a full-sized audio playback experience. It cannot be switched on or off.
Dirac HD Sound is for headphones, and in this case, specifically the OnePlus headphones. The technology can best be described as a kind of equaliser that optimises the output of speakers and headphones.
OnePlus and Dirac have worked together since 2015, starting with the OnePlus 2.
According to Erik Rudolphi, Dirac’s general manager of mobile, "At the core of both of these innovative audio solutions lies our desire to eliminate the notion that mobile devices, due to their physical properties, have limits with regard to the audio quality they can deliver. Dirac Power Sound and Dirac HD Sound challenge the audio constraints inherent in these devices and offer a rich, full and premium listening experience – as evidenced in the new OnePlus 6."
We have done a review of the phone and the audio output from the speakers is fine, but we noted that the mono sound was too limiting and that the sound gets drowns out easily if you are commuting or are in a park.
While we're certainly happy that OnePlus and Dirac are partnering to improve the quality of the sound, no amount of software is going to make up for the lack of a secondary speaker, or for the relatively lower speaker volume.