I tested both microphones of the Fractal Design Scape in wireless and USB mode. To review their sound and to compare it to other similar headsets, I used the Adam A7X speakers and Shure SRH840 headphones, both being studio monitors, connected to the powerful EVGA NU Audio Pro sound card, acting as a DAC, and the Topping A90 Discrete high-quality (pre)amplifier. The testing was done in Discord and Audacity, and I also used Audacity to record sound from the microphone. The sound was recorded with microphone sensitivity set to 100% and was not post-processed or edited in any way.
For reference, this voice recording was made with the Rode NT-USB, a high-quality studio microphone:
These are the samples recorded by using the "main," detachable, unidirectional microphone, first in 2.4 GHz wireless mode, followed by the same sample recorded in USB mode.
The main microphone's quality is excellent, with no noticeable difference between USB and wireless connections. My voice sounds natural and warm, thanks to the depth the capsule is capable of capturing. There are no distracting compression artifacts, and the mic isn't overly sensitive to plosives or background noise. All in all, you should have a great experience using the Scape's main microphone for a variety of purposes.
Now let's listen to the built-in omnidirectional microphone in 2.4 GHz Wi-Fi and USB mode.
As expected, the built-in microphone sounds much more compressed, but it will certainly do its job whenever you're not using the main microphone—i.e. when you're using the Scape outside your home.
The microphone sidetone feature, available in the Adjust Pro configuration tool, doesn't seem to do much of anything. While I generally like using sidetone with closed-back headphones, Fractal's implementation is lackluster—you simply won't hear your voice loudly enough, even with sidetone set to 100%. That completely defeats the purpose of this feature.