Staying true to their usual practice, Creative doesn't reveal the exact electronics used for digital-analog conversion or headphone power amplification. The undisclosed DAC is capable of working with up to 24-bit/192 kHz PCM audio files in stereo, 24-bit/96 kHz files in 7.1 surround mode, and 16-bit/48 kHz when reproducing Dolby Digital Live content through its optical output. The signal-to-noise (SNR) ratio of the integrated headphone amplifier is 114 dB, and the total harmonic distortion (THD) is 0.001%. Interestingly, these technical specifications are in fact slightly worse than those of the Sound Blaster X3 (32-bit/192 kHz audio file support, 115 dB SNR, 0.0004% THD), but in reality, there's practically nothing separating these two sound cards in terms of sound quality.

The headphone amplifier built into the Sound Blaster X4 has two gain settings, Normal and High. Creative recommends using the normal gain for headphones whose impedance falls within the 32–149 Ω range. At normal gain, the headphone amplifier provides 1.2 V RMS at 32 Ω. At high gain, which Creative recommends for 150–600 Ω impedance headphones, power delivery goes up to 2.3 V RMS at 150 Ω and 2.9 V RMS at 600 Ω.

I've gathered some of my headphones, speakers, and DAC/amps, and thoroughly tested the Sound Blaster X4 in all scenarios you might want to use it for, including games, music, movies, podcasts, and everything in between. Here's a list of the gear I used in my tests and comparisons.

Headphones and Gaming Headsets

• Sennheiser HD 660 S
  Philips Fidelio X2
  Oppo PM-3
  Sony WH-1000XM2
  Shure SRH840
  Drop + Sennheiser PC38X Gaming Headset

Speakers

• Adam A7X
  Edifier S2000 Pro

DAC/amps and Sound Cards

• Audiolab M-DAC
  Astell&Kern Acro L1000
  iFi Audio Zen DAC
  FiiO E10K
  Creative Sound BlasterX G6
  Creative Sound Blaster X3
  Creative Sound Blaster GC7
  EVGA NU Audio Pro
  Integrated sound card (Asus ROG SupremeFX S1220)

After over 50 hours of using the Creative Sound Blaster X4 and comparing it to various other DAC/amps and sound cards from my collection listed above, I was left with a very similar impression to the one I had after testing its predecessor. Aside from being absolutely packed with useful features, this sound card performs great. It's a straightforward upgrade to any integrated sound card, both in terms of sheer power output and sound quality. In a direct comparison to the fan-favorite Sound BlasterX G6, as well as the more expensive Sound Blaster GC7, the X4 sounds every bit as good and matches them in terms of tonality, too. The sound coming out of this external sound card is clean, distortion-free at any given volume level, and with a lively character. To bring out all of the energy and snappiness the Sound Blaster X4 has to offer, you do need to crank it up a bit, but I definitely can't say it sounds dull at lower volume.

With none of my headphones did I ever have to turn the volume knob on the Sound Blaster X4 past the 60% mark to get the loudness I'd be completely satisfied with, and that's with the amplifier gain set to Normal, which means there's some additional wiggle room for more demanding headphones, which can be used with the gain set to High. On more efficient headphones, such as the Shure SRH840 studio monitors, or most analog gaming headsets on the market, you'll rarely feel the need to go past 50% of the volume range, as the sound becomes uncomfortably loud.

One of my favorite pairings for the Sound Blaster X4 was with the Drop + Sennheiser PC38X (reviewed here, a beast of an analog headset. The combination is pretty much all you could ever need for a truly outstanding gaming and music listening experience. Of course, the Sound Blaster X4 pairs nicely with all other analog gaming headsets on the market, as well as many mid-tier hi-fi headphones, such as the Philips Fidelio X2, Shure SRH840, and Sennheiser HD 660S. I had a great time using all of them on this sound card.

Super X-Fi and Super X-Fi Battle Mode

One of the more pronounced features of Creative's newer sound cards, including the Sound Blaster X4, is the Super X-Fi technology. In essence, it's a combination of hardware (the built-in Super X-Fi ULTRA DSP) and software (head/ear mapping mobile app), which work together to create a listening experience of a multi-speaker system. To experience it to the fullest, you need a Super X-Fi-capable sound card, such as the Sound Blaster X4, and a pair of officially supported headphones.

To use it, you have to create a custom SXFI profile, which is done by scanning your face and ears in the SXFI App. After uploading your personal profile to the Sound Blaster X4, which is done via Bluetooth, all you have to do is press the SXFI button on the sound card, or within the Creative App. There's a regular Super X-Fi mode and Super X-Fi Battle Mode.

Let me start by saying that if you're not at all into virtual surround, Super X-Fi probably won't change your mind and turn you into a believer. However, as far as virtual surround sound technologies go, Super X-Fi is one of the better ones on the market. It dramatically widens the soundstage without destroying the bass in the process or making everything sound extremely artificial. Depending on the content, some artificiality and reverb can be heard, especially in the vocal range. Despite that, I at times really thought I was hearing sounds that originated outside of my head rather than a pair of speaker drivers close to my ears. I can't say Super X-Fi helped me pinpoint my targets in multiplayer shooters with extreme accuracy (that's where the Battle Mode kicks in), but it did create some interesting experiences. When Super X-Fi is paired with a game that has a high-quality multi-channel sound engine, such as Battlefield V, the results are great. The roar of tanks, screaming of planes, relentless gunfire, massive explosions—the whole chaos of the battlefield comes to life and hits you from all sides with an impressive effect of sound traveling "around the head." Multi-channel movies also sound great, but I regularly resorted to the traditional stereo mode for my music listening sessions. I also preferred using stereo in games with a more basic sound engine.

Super X-Fi Battle Mode is just as interesting. It's there to help you win your multiplayer first-person shooter matches, as it helps in the early detection of in-game targets. Unlike "ordinary" SXFI, the emphasis is not so much on the sound surround experience, but the best-possible assessment of the position and distance the sound is coming from. The "ordinary" SXFI is therefore more focused on improving the atmosphere and immersing you into whatever you're playing, while SXFI Battle Mode tends to give a competitive edge over opponents in multiplayer shooters. It is especially suitable when playing alone because you will not be confused by any amplified sounds coming from other members of your team.

For users who don't like Super X-Fi for some reason, the Sound Blaster X4 also offers the classic 7.1 virtual surround, which sounds noticeably more artificial and "flatter" when directly compared. If you don't use SXFI, you can activate the so-called Scout Mode, a mode that seeks to achieve the same thing as SXFI Battle Mode, but in a more primitive way. Scout Mode simply amplifies quiet ambient sounds so you can have an easier time hearing something you might otherwise miss. You'll also hear everything earlier than you normally would, which regularly made me paranoid. While SXFI Battle Mode at times struck me as borderline cheating, I found Scout Mode distracting more than anything else.