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Hands-on with the Grell TWS/1 in-ear headphone
Hands-on with the Grell TWS/1 in-ear headphone IBTimes / Jeff Li
Hands-on with the Grell TWS/1 in-ear headphone IBTimes / Jeff Li

In a market flooded with wireless earbuds, a newcomer is making a splash. Instead of the usual unsubstantial hype, the Grell TWS/1 is reputed to bring about a breakthrough in sound quality - its promise backed by a well known sound engineer in the audio industry, Axel Grell.

Can the first entry into the TWS earphone world bearing the name of the former Sennheiser engineer strike gold on its first try? Let's dive in to find out.

One of the most robust charging cases in the market IBTimes / Jeff Li

German Robust Case Design

The first thing you encounter with the Grell TWS/1 is its anodized aluminum case, which is more substantial than most. The robustness reminds me of the long line of German engineering tradition of tough and powerful machines. Both the lid and the main body of the case is made of a metal shell, and it's one of the strongest charging cases in the market that won't be coming apart anytime soon.

The base of the charging case is intentionally non-metallic, for the purpose of enabling the case for wireless charging. Some who have tried the TWS/1 found it too bulky to be pocketable, however the larger footprint is necessary for the inclusion of the wireless charging coil, as well as having a good sized battery that contains 4 full recharges. Aesthetically there is just something more elegant about the charging case standing upright on the desktop rather than lying down on its side.

The base is wireless charging enabled IBTimes / Jeff Li

The status light(s) on the charging case is also one of the most ambitious ones that I've seen, as it contains not one but four LEDs that act as a percentage bar, showing the amount of charge in the case, as opposed to most charging cases that uses colored LEDs to indicate the level of power remaining.

The TWS/1 charging case is not without its quirks however, first being the unintuitive placements of the left and right earbuds: the left is placed on the right, and vice versa. The design decision was most probably due to the profile of the earbuds that could only fit in such a placement. Another perhaps more significant issue is what seems to be the charging case being drained of power, which I found completely empty after not using the earbuds for 1-2 weeks. It's probably a good idea to make sure the case is trickle charged throughout the day to avoid any surprises, which to some may be a source of annoyance.

The TWS/1 is not only handsome, but sounds significantly better than TWS earphones till now IBTimes / Jeff Li

Setting New Standard of TWS Sound

Despite some quirks in the charging case, the promise of superb sound of the Grell TWS/1 is what launched it to the centerstage. Ask anyone who is serious about sound quality, and you'll detect yearning for true wireless earbuds to break the current status quo. I'm happy to report that the TWS/1 indeed sets itself apart when it comes to the listening experience.

Going with the same approach as Sennheiser, the Grell earphone does not rely on multi-driver arrays, or alternative driver technology like balanced armatures or magnetic planars. Instead through expertly tuning traditional dynamic drivers, the TWS/1 produces amazing staging and instrument separation with a single driver. The listening experience with the TWS/1 stands out due to this superior spatial sound, and adds depth to any music that is mixed with a decent soundstage.

While most see true wireless stereo earphones as an inferior product for personal sound as opposed to wired earphones, the sound of the wired earphones will in fact be impacted by the DAC/Amplifier that it's paired with. The good thing about TWS is that the earphone, DAC and amplifier have been rolled up in one, which means what you hear is exactly what the engineer - in this case - Axel Grell intended for you to hear - and it's glorious.

L-R: SoundID EQ On/Off, Firmware update, Gesture instructions and SoundID tests IBTimes / Jeff Li

Equalizing with SoundID

The natural sound of the Grell TWS/1 generally follows the Harman curve, but compared with other earphones, the mid-bass is more noticeable. It's a sound that would be liked by those who prefer a more punchy bass. However, if it's not to your liking, the TWS/1 can be coupled with the SoundID app, which allows for further tweaking of its sound.

L-R: Hearing test with 25 smaller tests, A/B EQ preference test, hearing test result, EQ preference result

The SoundID app itself is a scientific way to help one find their favorite equalization. It starts with testing your hearing ability, to ensure the equalizer setting is set according to how much your ears are able to pick up, as well as what the earphone itself can produce. Starting from your age and gender, it takes you through 25 small hearing tests to determine your ability to hear across a spectrum of frequencies. Finally, after choosing from a selection of music clips, the app presents you with a blind test of various EQ settings, and lets you choose between A and B settings without telling you what's being changed. The final personalized setting according to your own choice is then uploaded to the TWS/1, which can be toggled on or off in the app.

Compared with sound personalization technology like Nura's automatic personal EQ profiling, the SoundID process may be more time consuming and tedious, but it offers a more transparent process based on the user's own choice. The result is an EQ setting that is both pleasing to listen to, as well as feeling more grounded and scientific - an alignment with what Grell audio stands for.

The sound tubes are fairly short, which means eartips must be correctly selected to create proper seal IBTimes / Jeff Li

Importance of Tip Selection

While we're addressing the matter of sound, one of the most neglected but important aspects of in-ear earphones is the choice of ear tips. For the Grell TWS/1 earphones, because the sound tubes that go into the ear canal are fairly short, selecting the right tip is crucial to get the best sound from them.

I started with the tips that I usually go with - the large silicone tips, but I wasn't able to get a good seal. It's a good thing that the TWS/1 comes with a good selection of 3 pairs of silicone tips plus another 2 pairs of memory foam tips, and I was able to find the best fit with the largest foam tips. With a good seal, the sound was noticeably better, as well as improvement with passive noise isolation.

The robust earbud build with the large glass touch control surface IBTimes / Jeff Li

Touch Control with Gesture

The faceplate of the TWS/1 is made of a fairly large circular glass surface that functions as touch controls. The control gestures are fairly intuitive, and the long 3s and 5s hold commands are made simple through different sound tones that differentiate them - a design shared by Sennheiser TWS earphones.

When starting out with the TWS/1, I found myself accidentally triggering the controls often, due to the large and sensitive control surfaces. Over time however, I learned how to pick up the earbuds from the edges to prevent unwanted triggering, and it was a non-issue.

The Grell TWS/1 sets the new standard for TWS earphone sound IBTimes / Jeff Li

Final Verdict

The saying among audiophiles is: "you only know what you're missing when you hear it," and in the case of the Grell TWS/1, this is precisely the case. Though as a first entry for Grell Audio, there are some quirks as a earphone, it gets the most important attribute right - a new dimension of sound that sets itself apart from the TWS herd. With a superior soundstage, separation, as well as a scientific process for personal equalization, the TWS/1 is a worthy opponent against the plethora of TWS earphones on the market, and the leap in sound quality presents an exciting future for wireless earphones.


The Grell TWS/1 in-ear headphones with its excellent listening experience, stylish but formal German design from the earbuds to its metallic charging case, we award it with the IBTimes Recommended badge for business travelers.

You can order the Grell TWS/1 on its official website.

Sam is a production engineer turned tech writer who specializes in seeking out gadgets that enhances productivity while still looking sharp. This is a contribution to an ongoing IBTimes review series on EDC tech gadgets.