Smarter Every Day has posted a very nice example video of audio master Gordon McGladdery recording audio to be incorporated into slow motion footage. Since recording real slow motion sound that is usable at super high speeds is an impossibility due to the undiscernable pitch that results from it, you need to get creative with some reverb, echo, pitch, and chamber audio effects in order to get a compelling final product. We are big fans of both their channels and make sure you check them out for supporting them.
The HTC U11+ is a refined version of the U11 which was one of the better spec android phones of 2017. The new iteration boosts speed and a screen that goes from 5.5 inches to 6 inches. Space was accommodated for a larger screen without making the phone itself much bigger which is a feat of design and engineering.
For many, the big disappointment will be that it seems HTC is not making a US version of the U11 Plus and leaving it only for Asia and Europe at this time. The US market is very competitive and HTC has had a hard time penetrating the sales ranks of the Samsung, Apple and Google phones. If you indeed are able to get an HTC U11 Plus the Slow motion component has a 120fps full HD 1080p spec that should be competitive.
Nick Moore the creator of the Youtube channel of the same name has done a primer video on the recording of audio along with high-speed video. He goes into some detail about the usability aspects and limitations of recording audiothat is usable. Interestingly it can also mean you are better off faking the audio in post production for a better effect especially if you want it for a movie or tv show that demands quality audio.
The frequencies needed and data capture rate matter a lot in slow motion audio recording. In the end, it is a balancing act of what can be heard by the human ear and what you can exploit on reasonable time frames. It is much easier for example to record audio up to 240fps but it becomes increasingly less usable the higher the frame rate goes. At 1000fps you probably will not have anything worth keeping.