Epos gsx 300 review
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In 2019, Sennheiser Communications unveiled a new division dedicated to translating design, technology, and performance into high-end audio and video devices for both gaming and enterprise solutions called EPOS. The newly formed EPOS brand builds on a foundation of more than 115 years’ experience in audio and promises to pioneer the future of audio technology, such as their USB sound card, the EPOS│SENNHEISER GSX 300.

EPOS is derived from Latin and ancient Greek and is used to describe epic stories, speech and poetry. The name encapsulates our dedication to create solutions that enable ways of communication through the Power of Audio.


GSX 300 Review


The EPOS│SENNHEISER GSX 300 is an external USB sound card designed to level up your gaming experience and immersion while addressing the downfalls of onboard sound. Offering a simple plug-and-play in-line upgrade between your favourite headset and PC, the value-rich GSX 300 features high-resolution stereo audio, customizable 7.1 virtual surround sound and the EPOS Gaming Suite for Windows 10.

It’s easy to forget and is often overlooked that a headset is as only as good as the source you can provide. Onboard sound has seen significant improvement over the years but can still suffer from interference from high voltage components in your PC, resulting in undesirable noise or certain frequencies not being audible at all. Even in high-end motherboards features such as 7.1 virtual surround sound and software can be limited — This is where the GSX 300 looks to solve these downfalls by moving audio processing to an independent device and reducing the risk of interference.


Available in two colour variants; Black and White Snow Edition. The GSX 300 has a minimalist wedge design with a small footprint and an overall quality feel. The GSX 300 will complement any gaming setup. Featuring a large illuminated volume knob and customizable smart button on the front, while the rear of the GSX 300 houses the Micro-USB port and 3.5mm inputs for headset and mic.

Subtle touches such as the volume knob glowing blue for stereo or red for 7.1 virtual surround sound, along with a satisfying tactile feel when adjusting volume certainly doesn’t go unnoticed. I would have loved to see the volume knob double as a mute or an option to adjust the chat audio mix but unfortunately, these might have to wait for a future model. The GSX 300 weighs in at 160 grams and coupled with thoughtful design and large rubber feet prevent any movement while adjusting the volume.

The GSX 300 is only 91mm long, 81mm wide and 41mm tall. This small and compact form-factor is ideal for the GSX 300 to be stored in a laptop bag for mobile gaming on the go.


The Micro-USB powered GSX 300 is capable of driving headphones with an impedance of 25 – 75 Ω and is high-resolution ready. This means that the GSX 300 is capable of 24 bit / 96 kHz sampling rate which is beginning to become more common in PC audio and gaming applications. High-Resolution audio is defined as lossless or uncompressed, meaning there is no compression applied to the audio source to allow you to listen to the audio the way it was truly intended to be.

In addition, the GSX 300 also supports customizable 16 bit / 48 kHz 7.1 virtual surround sound (with hi-res surround sound in the future) that is enabled thought the EPOS Gaming Suite or the physical smart button. The large volume wheel is synchronized with Windows 10 and is handy when switching between output devices and adjusting volume levels while in-game.

Many users will assume that the GSX 300 is solely for PC users, which is incorrect. The GSX 300 is also USB compliant, meaning it can be connected with USB compliant devices such as a PlayStation 4 or even a docked Nintendo Switch to allow for stereo mode operation.

Audio Performance

When it cme to testing the GSX 300, I decided to opt for my trusty EPOS│SENNHEISER GSP 500 — an open-back acoustic headset that has been my daily drivers for the last few years. I’m so used to the open-back design now I would be hard-pressed to make the move to something else. Ideal in quiet environments, the open-back ear cups allows for a more natural sound and provides a more open listening experience, plus they are excellent for hearing pizza deliveries!

I must admit that before testing the GSX 300 I was a little sceptical as I had purchased my Z390 AORUS MASTER purely for its impressive specs regarding onboard sound. While it does deliver on some of those promises, they were soon shadowed by the sound quality alone that the GSX 300 provides. There was an obvious improvement as soon as I swapped between the onboard sound and the GSX 300, it was like music for my ears!

The sound signature was warm, clear, and more detailed, while the bass was deeper and mids more defined. After spending some time down the rabbit hole searching out FLAC versions of my favourite tracks in TIDAL, I found myself returning the cable to the GSX 300. Both the Natural and Music equalizer profiles worked as expected and the Smart Button was surprisingly convenient when changing genres. This allowed for quick switching of profiles to suit what’s playing.

From the moment you enable 7.1 virtual surround sound and jump into Call of Duty: Warzone, you notice that the sound stage is noticeably wider. EPOS utilizes their own proprietary surround sound engine and I was surprised; it was fantastic, especially compared to my HyperX Cloud II‘s. Action and small ques become elevated and provide a better sense of noise location. Playing Shadow of the Tomb Raider created a more centre of any given space with areas feeling larger and more open without losing out on detail. You can also adjust the reverberation in the EPOS Gaming Suite to tweak the experience.

If you are strapped in for a serious competitive session, then make sure you enable 7.1 Surround Sound. The already wide sound stage of the GSP 500 and the e-sports eq profile is perfect for games like CS:GO and VALORANT and can yield some nice results. While not all genres will play to the benefits from 7.1 virtual surround sound, it is a nice feature to have and at $129 AUD it’s certainly a welcomed feature to the GSX 300.

Microphone Performance

Testing the GSX 300 and the EPOS Gaming Suite voice features via the GSP 500’s boom mic also provides a notable step-up in chat quality — I even received comments asking if I had a new mic!

The Voice Enhancer feature lets you adjust between warm and clean voice profiles. The warm profile fills the voice out and adds a nice boost in bass and quality. This would even work well for Zoom or Microsoft Teams meetings. I found the clean profile more fitting for in-game comms as it provides a less detailed, clear voice that suited to compete with game noise.

EPOS Gaming Suite

The EPOS Gaming Suite takes control of the GSX 300 with its intuitive and clean user interface. This software is able to provide access to audio EQ, voice enhancements, and surround settings with minimal fuss.

The Audio section includes a limited selection of equalizer presets including music, esports, flat, and movie, along with the option to customize and save your EQ settings. These presets can be changed on-the-fly via the Smart Button on the front of the GSX 300, which can also be assigned to toggle between stereo and 7.1 output. Unfortunately using the Smart Button to toggle the surround effect on the fly, doesn’t actually apply the mode. To apply the effect I needed physically click the option in the EPOS Gaming Suite, definitely a bug I hope EPOS address.

The voice page lets you adjust voice profiles as well as gain, sidetone, noise gate and noise cancellation for removing unwanted keyboard clicks or background noise.


Epos│sennheiser gsx 300 review


  • Sound quality
  • 7.1 Surround Sound
  • Value
  • Build quality
Epos│sennheiser gsx 300 review


  • Single output
  • No Mac support
  • 91%
    DESIGN - 91%
  • 85%
  • 74%
    SOFTWARE - 74%
  • 90%
    VALUE - 90%


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The EPOS│SENNHEISER GSX 300 offers a great value alternative to onboard sound, adding features and boosting both audio and chat quality. Paired with a gaming headset will allow the GSX 300 to drive it with new potential.

For more on EPOS, check out our previous coverage.

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Written by Chris Carew

“Sometimes the easiest solution, is the last thing on your mind” - DashieGames, 2018