The microphone of the HyperX Cloud Revolver S was tested by connecting it to the Asus ROG MAXIMUS IX CODE motherboard.
To review the microphone's sound and compare it to those of similar headsets, I used the Adam A7X speakers and Shure SRH840 headphones, both being studio monitors, connected to Audiolab's M-DAC, a high-quality digital-to-analog converter that functions as an external sound card when connected to a PC. Testing was done in Discord, TeamSpeak, Skype, OBS Studio (used for Twitch and YouTube streaming), and Audacity, and I also used Audacity to record sound from the microphones. The sound was recorded with the microphone's sensitivity set to 100% and was not post-processed or edited in any way.
For reference, this voice recording has been made with the Rode NT-USB, a high-quality studio microphone:
This is the sound recorded with the bidirectional microphone the HyperX Cloud Revolver S is supplied with, with the microphone connected to the supplied sound card:
The microphone's sound quality isn't necessarily spectacular, but it's quite good regardless. The voice is clear, doesn't sound too compressed, and even has a certain amount of depth. I wouldn't have any qualms in recommending it even for more serious usage cases, such as Twitch and YouTube streaming. It should be mentioned, though, that you can get even more from the microphone than the supplied sound card allows you to. That's something that became perfectly clear to me after I connected the headset to a different external USB sound card (Creative Sound Blaster E1) as well as my motherboard (Realtek ALC S1220 audio codec) by using the supplied TRRS-to-dual TRS splitter cable. Take a listen:
It's very audible in both cases - my voice becomes deeper, clearer, airier, and significantly less compressed. In this case, I'd even declare it good enough for YouTube voiceovers, which is quite a feat for a headset microphone, especially since I'm quite strict in that regard. In short, this is a very good microphone slightly hindered by the supplied USB sound card.
Let's listen to a few other microphones on various gaming headsets, starting with the "regular" HyperX Cloud Revolver connected to an external USB sound card: