EPOS | SENNHEISER GSX 300 Review — Sound Blaster

A long time ago in a tech galaxy not so far away, computers needed a sound card so you could actually get any audio output. Those were the dark days when 1Gb of RAM was an insane amount and 480p CRT monitors were still a thing.

Having a Creative SoundBlaster card in your machine meant you were posh. Today, almost nobody even knows what a sound card is because most motherboards have them built-in. 

This is where the EPOS | SENNHEISER GSX 300 comes in. Turns out, not everyone has a fancy computer with surround built into the motherboard. And with more games and movies encoded with not only hi-res audio, but also surround sound, many are missing out on the experience.

A lot of gamers are also looking at investing in higher-end headphones for a greater tactical edge but those typically need more power to run than most computers can give. These are the people EPOS is targeting and I think they’re on to something here. 


The GSX 300 is an external USB sound card that allows your computer to output hi-res audio 24 bit at a sampling frequency of 96 kHz stereo. For reference, most of what you listen to from online streams or from CDs (those shiny, silver discs from the last decade, remember?) is 16 bit at 44KHz sampling. So you get an immediate and noticeable boost especially if you have the right sources. Additionally, the GSX 300 outputs virtual 7.1 surround sound at 16 bit and 44 kHz. 

The GSX 300 is easily powered by any USB port on Windows PC which gives it enough juice to drive any headphones with an impedance rating of 25 – 75 Ohms. True audiophile headphone owners will need to look elsewhere for something that can power their fancy $2000 headphones but for most consumer headsets the GSX 300 is plenty powerful.  

All this audio wizardry is contained in a tiny, wedge-shaped box which measures only 9cm long, 8cm wide and 4cm tall. This makes it perfect for carrying around in a bag, especially for laptop users. The whole thing is encased in a smooth plastic and looks seriously dope; blending beautifully on your desk. It comes in two colours, Black and a White Snow Edition — which is what I have here for review. Two rubber strips underneath the unit keep it from sliding around surfaces. 

On the front is a large, smooth, volume dial that has a nice clicky feel when you turn it. Next to it is a configurable button that can be configured to cycle through your EQ profiles or switch between stereo and surround sound. An LED ring of light shines around the dial when the unit is on and adds to the dope look. The light changes colour too; blue for stereo mode and red for surround mode. At the back are the standard 3.5mm headphone and microphone outputs as well as a Micro-USB connection to your PC. Sadly, the GSX 300 won’t work with Macs or consoles but hopefully, EPOS will remedy that in the next iteration.  

Audio performance 

I tested the GSX 300 using three different headsets – the EKSA E900 Pro, Razer Thresher TE and my trusty old pair of Sennheiser Momentum 2.0 headphones. The first thing I noticed was just how much louder my headphones were. My Momentum 2.0’s need Windows volume of about 80% when plugged directly into a PC but only 15% when plugged into the GSX 300. It was generally the same for the other headphones and I’m amused how often I found myself ‘reducing volume’ instead of increasing it. 

I did some extensive listening sessions and the most obvious takeaway is that everything sounded brighter and with more punch and power. The mid and low-end spectrum saw a boost leading to warmer tones and more bass. All the headsets I tested saw incremental improvement in audio quality but don’t expect the GSX 300 to suddenly transform your headphones into Audeze cans. The GSX 300 is like that drink V – it’s you, but better.   

The one thing I was keen to try was the virtual 7.1 surround sound that GSX 300 will give any regular headphones. Now don’t get your hopes too high here either because while it does work, the effect is also less dramatic than I’d imagined. What you do get is more of a sound stage expansion, making things sound further away from your ears rather than in your ears. It’s hard to describe but switching between stereo and surround, you quickly get what I mean. In stereo mode, the sound is closer to your ears, like the source is right next to you – it’s more intimate. Surround doesn’t feel as intimate but boomier and more cinematic with more echoing or reverberation. 

I tested the surround sound across games, music and Netflix and the result was more hit and miss than consistent. In some things, the surround was expansive and impressive, like when I watched Cursed on Netflix. However, in games like the Witcher 3 or The Division 2 where I expected the surround to enhance the big, open worlds, there was barely a difference compared to stereo mode. Hmmm. In games, the big thing missing was verticality. The audio sounds great sweeping around you in both modes but you don’t get any sense of things above or below you. It’s rather bizarre. 

I even used the oldie but goldie Virtual Barber video on YouTube which is a great way to test surround sound. It simulates a visit to a barbershop for a haircut and is pretty impressive. However, it’s amazing when you hear the barber shave your hair from the right ear to the left but when he goes to the top of your head, the sound just feels flat in the middle of your ears. You don’t get any sense of height. This, as you can imagine will be a problem in competitive games where you need complete awareness of your surroundings or you get dead.

Tweak that sound

Thankfully, EPOS gives you plenty of control to adjust the various sound modes to your heart’s content through the EPOS Gaming Suite software. The software is honestly quite simple and intuitive with three tabs for audio, microphone and settings where you can change the function of the front button or update the firmware. Everything is laid out clearly.

You can tweak the sound curve to get more bass or accentuate vocals. There are four presets that come in the software; Flat, Esports, Movie and Music. It’s a simple matter to add your own with a click of a button next to the profile dropdown. Beneath that is the option to switch between surround and stereo. Once surround is activated, the reverberation slider is unlocked. Sliding it further to the right increases the space-iness of the sound. Again, your mileage will vary depending on what you are watching or playing. 

One odd thing I encountered was that when you try to change the sound mode using the preset button on the GSX 300, it doesn’t actually work. The light ring changes colour but the sound doesn’t change. You have to manually set it in the software before it activates. This is irritating since you then have to get out of whatever game you are playing to manually switch sound modes. It does, however, work perfectly for switching between EQ presets so it’s clearly a glitch that EPOS needs to fix in a software update. Thankfully, EPOS has sent out a software and firmware update in the short time I’ve been testing this so I expect it will keep getting fixes and improvements. 

Wanna sound like Barry White?

The microphone tab gives you options for tone, gain and noise cancellation. It works reasonably well but as with audio playback, don’t expect the GSX 300 to make a bad microphone great. The very same features that were available to the excellent GSP 370 headset mic are now available to any microphone thanks to the gaming suite. It offers three voice enhancement profiles; Off, Warm and Clear. There is a very immediate and profound difference between them.

Warm adds more bass and overall warmth to your voice while Clear strips away any unnecessary frequencies to present a clear representation of your voice. This mode sounds more processed to me and I generally prefer the Warm settings. There’s additional settings for Gain, Sidetone which is how much of your own voice you hear played back through the speakers and Noise Cancellation. I wasn’t impressed with the noise cancellation but again, the GSX 300 can’t make a bad mic great. 

Overall, it works very well for most mics and the settings are pretty easy and straightforward to use. If you are a professional streamer or podcaster who needs more control, there’s tons of options out there.


The $130 EPOS | SENNHEISER GSX 300 is a great little addition to your gaming and media arsenal. If you have a good pair of headphones, your experience will be much better. And while it’s good for a desk setup, I think the real winners will be laptop users. Most PC desktops have decent onboard sound cards, unlike many laptops. 

The GSX 300 ensures that people with lesser machines will have a great audio experience and even surround sound that they normally would be missing out on. Your Netflix binge sessions will see a definite improvement. Gaming was hit and miss for me but I expect EPOS’s processing engine will get better with time. Overall though, game and media sound is more powerful through the GSX 300. Now it’s time for me to finally buy a pair of planar headphones to pair with this cutie-pie. 

EPOS provided the GSX 300 to PowerUp! for the purpose of this review.

Beautiful, portable design
Great with any wired headphone
Mic enhancements
Surround sound is hit or miss
Works only on PC

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Kizito Katawongahttp://www.medium.com/@katawonga
Kizzy is our Tech Editor. He's a total nerd with design sensibilities who's always on the hunt for the latest, greatest and sexiest tech that enhances our work and play. When he's not testing the latest gadgets or trying to listen to his three whirlwind daughters, Kizzy likes to sink deep into a good story-driven single player game.

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