I'll split the audio performance analysis into two parts - gaming and music. Even though the headset produces the same sound regardless of what it's being used for, you won't necessarily look for the same things while annihilating your virtual opponents as you will when listening to your favorite tunes.
Gaming
A big chunk of HyperX's reputation was built on the excellent acoustic performance of their gaming headsets, which is why I considered their decision to redesign the built-in 50-millimeter speaker drivers somewhat risky. Luckily, it only took me about three minutes to fall in love with the sound of the Cloud Alpha. It sports a new dual chamber driver system where the bass is coming from one chamber and the mids and highs from another. Of course, all frequencies come together before reaching your ears, so you don't have to worry about hearing them separately. I invite you to take a look at HyperX's own video that explains the dual chamber design in more detail:
The general idea is to add more clarity to the sound by making the bass fat and powerful without having it spill into the midrange. This isn't just a nice marketing tale - after directly comparing the HyperX Cloud Alpha with the Cloud Gaming, the improvements can easily be heard. My ears can't quantify them like that video did (in case you didn't watch it, it claims that the Cloud Alpha has 34% less distortion than the Cloud Gaming), but the difference is there, and it's a significant one. The same applies to a comparison of the Cloud Alpha to the Cloud Gaming II.
If I had to name one thing that strikes me as most impressive acoustically, I'd have to go with the sheer fullness of the sound. As soon as you fire up a game, you'll get a feeling that your entire head is completely encapsulated by the in-game audio. That's mostly achieved by the richness and warmth of the bass alongside a detailed midrange and crisp highs. It doesn't matter which genre you prefer and mostly play - everything sounds terrific on the Cloud Alpha. I was similarly happy with the sound while blasting my way through Wolfenstein II: The New Colossus, exchanging fire with my opponents in PUBG and Battlefield 1, and playing games that rely more on atmosphere and dialogue, such as Life is Strange: Before the Storm.
The HyperX Cloud Alpha isn't only fun and enjoyable to listen to, but also quite accurate in terms of spatial positioning. The soundstage is significantly wider than that of the Cloud Gaming, which automatically makes figuring out where you're getting shot from easier. After over 300 hours invested - or wasted, if you will - in PUBG, I've learned to appreciate that feature more than ever. Even though I've tested more neutral and slightly more informative gaming headsets this year, such as the SteelSeries Arctis 5, the Cloud Alpha is pretty much unmatched in the way it balances precision and pure joy, especially in the $100 price bracket.
Thanks to the great seal that it forms with the head, the Cloud Alpha doesn't leak any sound in either direction.
Music
HyperX's entire headset lineup is known for being equally good for gaming and music. The Cloud Alpha takes that versatility to a whole new level. The warmth and fullness of the sound, the sheer amount and puchiness of the bass, the subtlety and presence of the midrange, and the clarity of the highs make it amazing for listening to your favorite tunes. I'd have no problem recommending this gaming headset to someone after a pair of midrange hi-fi headphones mostly for use with music and no intention of using the microphone - assuming they don't mind the gaming aesthetics.
I listen to a wide selection of music genres, and the playlists I use for headphone testing cover even more of them. The Cloud Alpha was able to handle all of them equally well. I wasn't able to overwhelm it with songs with excessive bass, or those focusing on complex guitars and high-pitched vocals, male or female. The tuning of the 50-millimeter speaker drivers is simply excellent.
Even though the 65 Ω impedance of the Cloud Alpha is unusually high, I should mention that I had no trouble getting plenty of volume from an integrated sound card or even my Android smartphone. Using this headset on-the-go is a viable option as long as you don't mind standing out in a crowd due to its design. You can simply leave the microphone at home and utilize the shorter 1.2-meter cable HyperX supplies, or any other 3.5-mm audio cable at your disposal.