qdc Gemini
k.e. 2017

qdc Gemini Review

Sound Impressions


While the Gemini fall into the neutral category of monitors, they have a slightly warm tuning that draws the focus on the midrange. The presentation is very convincing and easy to listen to. Do not mistake them for reference-flat studio monitors, though, as the bass can pack a punch if asked for – especially with optionally activated boost.

The treble is smooth in tuning, has great extension, and adds detail to the high resolution. Overall, the tuning is aimed at convincing natural reproduction with just a pinch of added musicality.


Bass Switch

First off, the Gemini has a physical bass switch on the outside of the faceplate like first seen on the Vision Ears VE6 Xcontrol. When activated, the switch adds up to 4 dB in the sub-bass and just around 2 dB in the upper bass.

Default Setting

By default, the Gemini has around 5 dB bass above a flat-tuning which is an adequate amount for in-ear compensation and it should be perceived as natural by most listeners. For me as an experienced IEM user, I find the quantity to be just slightly boosted but nonetheless very enjoyable and not distracting.

The bass draws a straight line with no prominent emphasis in any frequency range. This allows punch and texture in equal terms and adds to a musical and lively presentation.

The bass is very tight and detailed but the extension leaves me wanting just a bit more at the low end. The switch does add a few dB more but the boost is distributed broadly, subjectively not improving the extension at lower volumes.

Switch On

Where the bass switch shows the strongest impact that I noticed was with At DOOM’s Gate from the referenced game soundtrack by Mick Gordon. The beginning of the track has a repeating hard-hitting 40 Hz boom accompanied by some atmospheric overlay.

At a very loud listening volume, which should only be done for very short listening periods, the default setting creates some decent rumble that’s similar to a distant earthquake. But once you hit those switches, that bass track feels like an electric hair trimmer on your skin moving from the temple to the back of your head.

Genre Matching

Neither setting shows audible distortion. The bass track remains equally tight and precise even when boosted. The switch also works very well with Hip-Hop and Rap have low-hitting beats. I locate the bass of Murs’ G.B.K.W. at around 50 Hz and that’s when the difference is most apparent. The added oomph subjectively adds to the experience.

More radio-friendly Pop tracks often place their beat at around 100 Hz and above. That’s when the switch is slightly less effective and adds more overall warmth than impact. Furthermore, when dusting off Pantera’s Vulgar Display of Power, the bass guitar can just tip over to being too boomy. I noticed this with several Rock and Metal records.

There are some tracks that just sound better with the switch and some without. My experience so far is that I use it 20% of the time, very rarely for my preferred genres Classical and Jazz. Anyway, the bass switch proves to be very delicate and it is very useful to have. Trust me, you want to use it on the latest when RATM’s Bombtrack kicks in.

qdc Gemini


Star Vocals

The Gemini wants to be balanced all across the frequency range and try to come off as neutral, but, to be honest, the vocal range is the real star of the show. The midrange is very enjoyable with a weighty timbre and great plasticity.

Compared to a reference tonality, the vocal presence is just a bit softer, and thus the Gemini bypass any unwanted crunch or shrillness.

As an effect, I caught myself raising the volume several times far above my average listening level, and fully getting lost in the music. Especially vocals – male and females equally – and mid-centric guitars just simply pop and stand out as highly musical. Never are they fatiguing, never lacking; this could be the sweet spot for many.

Upper Mids

The upper midrange does a great job of capturing details but not taking away from the musicality. While I was writing these lines and shuffling through my library, I wanted to drop a dozen examples of where the midrange is especially luscious, but I gave up trying to find a counter-example.

It’s simply enjoyable with a convincing timbre, great details, and an uncolored softness that works for instruments (guitar and piano) just as well as for voices.

Switch Effect

The bass switch has only very little impact on the lower end of the vocal range and both switch settings do a formidable job at separating vocals and instruments in the sound sphere.

The bass switch does add some extra weight and presence to low-tuned guitars but its effects are very subtle in the midrange. Ultimately, the default position creates even better contrast and is my preferred choice for most recordings with vocals.

High frequencies

Brilliance Peak

The Gemini has a rarely seen (or more appropriately ’rarely heard’) subtle treble peak above 10 or even 11 kHz. Calling it a peak would actually be an exaggeration. However, this is rather uncommon for multi-BA receivers, which often quickly lose output pressure in this higher range of frequencies.

The Gemini, however, pump out even just a bit more volume in this area than my ears would consider linear while boasting technical prowess. This results in a slightly bright treble tuning that starts with a subtle relaxed recession and builds up to an emphasis on higher notes, which in total balances to just the right amount of treble.


Fortunately, the frequencies above 10 kHz do not add to sibilance so there is no sharpness in its presentation. In the worst case, I would describe Gemini’s treble characteristic as very textured, which when paired with sub-optimal gear can feel slightly brittle or fuzzy.

Most of the time, the treble knows how to impress, though. In all the 219 times (a vague estimate) I heard Michael and Janet Jackson’s Scream, rarely have I been this engaged in all the glass shattering and shards flying through the room.

They come crashing from all sides in an amazingly surrounding environment and I just kept moving my head as if I were watching a tennis match while seated in the front row.


This track is definitely a showcase of the Gemini as the tuning works best here. Hearing the glasses break just sounds phenomenal and the clarity is insane. Violins also stood out as very enjoyable with an airy sound.


On the other hand, the treble performs worst when digging up some heavily compressed Thrash Metal or Garage Rock. Technical limitations on the recording just don’t provide enough space for the Gemini’s treble response to breathing and can sound like they are cut off.

The Gemini try to emphasize something that is not there. It’s not the earphones’ fault, but there are IEMs that will cope better and in this rare selection you can forget that you spent your money on a TOTL custom. Ergo, high-quality recordings will scale to sound much better.

qdc Gemini


The presentation and imaging are very coherent and neither draw attention to width nor depth. There is decent space for all instruments and layering works very well. The distance between listener and recording depends a lot on the source but the listener is never closed in or pressed.

The sound feels very dynamic as it has a lot of room to breathe. It helps that the Gemini doesn’t have any forward peaks in the frequency response. Activating the bass will create more intimacy and pull the rhythm section in. This creates more depth but I prefer the vocals to have at least as much presence as the bass.


The qdc Gemini wants to be a high-end TOTL monitor and luckily they achieve that. The bass is very tight but just loses by a hair to the speed of Andromeda or VE8.

They still manage to outperform the PP8 and NF6 in this regard. In the treble, the Gemini need a good source to provide enough speed, but with decent amplification, the notes have excellent decay and great clarity. There is no clouding that would hurt micro-details.


Nintendo Switch

I know the Switch is not an audio device, but I am using it here as an example of the ridiculous sensitivity of the qdc Gemini. The picked-up hiss is so strong, that the Gemini is almost unusable.

This is more than just a little annoyance or distraction in the background. Luckily we don’t use the NSW to listen to audio but if you are planning to grab the Gemini, be sure to save some money for appropriate gear.

ifi iEMatch

Thankfully the Gemini is very easy to drive and they will reach high-pressure volumes quickly. If you know that your smartphone or other primary device is not clear from hiss, there is hardly a way past the ifi iEMatch or EarBuddy. The Gemini can easily handle the ultra setting and still pump out loud enough volumes.

I do recommend the ultra setting over the high setting because of the lower output impedance. I found the midrange and treble sounded slightly smoother and more homogenous with lower output impedances albeit being a relatively minor effect. Higher output impedance boosts bass, too.

qdc Gemini

Hugo 2

qdc manages to uncover a very slight background hiss from Hugo 2 but you will have to focus very carefully. It does create a less dark background and overall lifts the timbre to a more lightweight presentation.

The second iteration of “(everywhere) You-Go” allows much more precise volume adjustments and this helps a lot with the easily driven Gemini. (I double-dare you to reach the orange color on the volume regulator!).

Soundstage, texture, speed, and detail are mind-blowing in this setup. In fact, the treble gets refined to the point that it loses its fuzzy character that I mentioned earlier. The Hugo 2 is possibly one of the best ways to experience the full potential of the qdc Gemini.


Germany’s favorite multi-purpose DSP machine with dual/balanced head-amp returns and the Gemini does a formidable job at capturing its character.

Compared to the Hugo 2, I subjectively perceive the bass as a tiny bit softer with less texture and also the midrange sounds more distant. The treble is equally tight and enjoyable, though high notes sound a bit darker even with the SD Sharp filter.

The effects of the crossfeed were very apparent and I preferred to turn it off for the Gemini. This combo sounds very saturated, but even more mid-focussed emphasizing on the CIEM’s strengths. I am torn between Hugo 2 and ADI but because of the tighter bass, Chord receives the nod over RME this time.

Select Comparisons

InEar ProPhile 8

Linear Almost

As a fan of neutral tuning, for me, the ProPhile 8 is one of the very best IEMs released recently.

Fortunately, there has been a very prominent trend in the high-end category of IEMs in favor of a more linear tuning, but despite lowering the bass quantity and refining the treble, a plurality of sound designers still add some warmth to their products as they believe that is what the majority perceives as natural or realistic.

There is a lot of truth to that because let’s be honest, probably nobody’s living room sounds like a perfect studio environment – at least not if the room has any furniture or windows in it. Having that said, the ProPhile 8 is tuned more realistic and uncolored to my ears than the slightly warm but nonetheless just as enjoyable Gemini.

Listening to Demand

qdc picked up on the market trend and tuned their flagship according to popular demand. I have read a few opinions of people saying the PP8 sounds shrill or bright and I guess there’s a very high possibility these people would consider the Gemini as neutral or linear.


Gemini and ProPhile are different in almost every way. Starting with the bass, the ProPhile not only have 2-3 dB less low-end pressure, but they also try to compensate the sub-bass which is more in line with targets by Sonarworks or Harman.

On the other hand, the Gemini features bass warmth with a general broader elevation. This is no less justified as it reminds me of very popular models like the Campfire Andromeda or VE8. The Gemini does have less bass quantity than the aforementioned, but the character is overall similar.


Both monitors, Gemini and ProPhile, have a bass switch with a comparable bass boost of 3-4 dB. The Gemini does boost the bass a bit broader, which results in more warmth, whereas the PP8 adds more pressure to 150 Hz and below, which creates an even bigger contrast to mids and treble.

But to be honest, I hardly ever use the PP8’s switches because I simply can’t reach them with my fingernails and I have no convenient place to put the tool within easy reach.

In the midrange, I think the PP8 deserves to be awarded as a reference. But as already mentioned, not everybody will agree. Coming from the PP8, the Gemini can sound a bit dull as they cut back at least 5 dB at 3 kHz.On the other hand, after using the qdc for one week, the ProPhile sounded nasal and too forward. This is just how our brain works and adjusts to different tunings.


As with the warmth, the Gemini’s mids are more in line with the Andromeda (at >3 ohms OI) and if you look at Campfire’s success, that is definitely not a bad thing. In the upper midrange, the InEar ProPhile does not shy away from presence. Again, the Gemini is more relaxed but since the presence area is cut back slightly, details are not clouded at all.


The main difference in the treble is that the ProPhile shows more clarity. Dips and peaks are so minor that they go unnoticed for my ears and the sine sweep sounds equal across the board until the PP8 quickly cut-off after 11 kHz. The Gemini starts smoother in the lower treble but then picks up presence at the top end where the PP8 loses breath.

As discussed earlier in the review, this could be due to insertion depth and better sonic conditions due to comparing a CIEM with a universal, but in this comparison, the Gemini has a much better treble extension. They have a stronger wow factor and you could argue the Gemini perform more in the interest of high-end as they push technical limitations.

The Gemini will ask for decent (and especially distortion-free) amplification, though. The ProPhile are less demanding and in the end, I think their treble does sound more realistic. I do suggest ignoring the PP8’s treble switch.


Imaging with both monitors is very good, but the feeling is different. The PP8 sounds more open and more expansive in width. The Gemini sounds more intimate overall, but at the same time, the presentation is more relaxed.

The soundstage of the Gemini reminds me of smaller venues with high ceilings and with the listener being somewhere in the first 10 rows. It’s emerging and convincing but I have difficulties creating such a scenario in my head with the PP8.

Overall, there is no winner in this matchup. You either want a studio reference sound or you don’t. If you do, the ProPhile 8 will be your preferred choice. I do think that most customers will have an easier time adjusting to the Gemini and appreciating the musical character. Ultimately, the Gemini manages to outpace the ProPhile in speed.

Our Verdict

At almost two thousand dollars, the qdc Gemini is not a steal. But for that, you not only get a very good monitor, but also the whole high-end experience: beautiful design, perfect fit, flawless production, a nice case, superior cable, and adequate packaging.

The tuning of the 8 BA receivers is done very delicately. The Gemini sound more musical than a reference tuning but they still provide overall great balance among bass, mids, and highs. They also scale very well with better equipment and I am interested to see how much I can push them in the future.

The bass switch is nothing I asked for, but surprisingly I use it a lot. Once I get on the tram, I subconsciously automatically flip the switch. When I arrive back home, I flip it back. Independent of the music genre, the sound is very saturated, melodic, and easy to listen to, yet provides ample texture and great micro-details.

The qdc Gemini has been my daily driver for the past four weeks and they will surely continue to keep this spot for a while.

qdc Gemini Technical Specifications

  • 8 balanced armature drivers
  • 4-way crossover
  • crossover-switch for bass tuning
  • noise isolation: 26 dB
  • frequency response: 20 Hz – 20 kHz
  • impedance: 25 Ω
  • sensitivity: 112 dB SPL/mW

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