First of all, I should state that I am an Oculus developer, a member of Oculus Start, and was honored to be part of Oculus Launch Pad 2019. What follows is a suggestion that I would like to pass along to the Rift S team.
The audio quality on the Rift S has been abysmal since launch. It is tinny, thin, and quite frankly it sounds terrible. This is 100% solvable by using a simple EQ and limiter (to protect the speakers from excessive signal peaks).
I have long since solved this problem for myself by installing EqualizerAPO (https://equalizerapo.com/) and adjusting the EQ curve on the Rift S audio output device. The only additional step I've taken, other than EQ, is to add George Yohng's W1 Limiter VST plugin (http://www.yohng.com/software/w1limit.html) to the end of the signal chain.
Attached you will find my configuration file for EqualizerAPO as well as screenshots of my settings.
Unfortunately, asking users to install a 3rd party solution to improve audio quality is quite absurd. Almost no one but me will do this, and that includes other developers.
Please pass this information along to the appropriate teams. I encourage Oculus to modify the existing default EQ settings to something similar to these, as the resulting improvement to clarity and quality is tremendous.
Thanks for your time. Please contact me if you have any questions.