Truthear ZERO RED vs CCA DUO Review

Truthear ZERO RED vs CCA DUO Review

Truthear ZERO RED vs CCA DUO Review – Battle of 2DD IEMs

It has been nearly 1 year since the TRUTHEAR x Crinacle ZERO was introduced. And now a new collab version is showing, the TRUTHEAR x Crinacle ZERO RED, which was re-tuned based on a successful precursor.

The ZERO RED houses a double dynamic driver configuration, 10mm and 7.8mm like the original ZERO. It adopts a dual polyurethane suspension composite liquid-crystal dome diaphragm dynamic driver with an N52 Rubidium magnet double-cavity internal magnetic circuit.

The CCA DUO is also a dual-dynamic IEM with two 7mm dual magnetic & dual-cavity dynamic drivers. It consists of a front and rear cavity, which doubles magnetic flux.

Truthear ZERO RED vs CCA DUO Review


“The nozzle length and the slightly wider nozzle tip of the ZERO gave me hard times. Depending on your ear you might struggle to find the best fit. My ear canal started to hurt with stock tips as the nozzle is longer than usual.” These are what I wrote in my OG ZERO review. And this hasn’t changed on the RED too because both use exactly the same shells without any change. Although there are many complaints about this problem, Truther chooses to do nothing about that. The relatively thick nozzle of the ZERO RED can be a deterrent to some.

Truthear ZERO RED vs CCA DUO Review

The CCA DUO on the other hand has a smaller shell which is far more ergonomic than the ZERO RED. Because it uses two 7mm drivers it has a volume advantage in design. The length and the width of the nozzle are on the standard size, the DUO fits perfectly in my ears.

Truthear ZERO RED vs CCA DUO Review

Tech Inside

The Truthear x Crinacle ZERO RED uses two dynamic drivers of the same composition—a liquid crystalline polymer (LCP) composite diaphragm and polyurethane (PU) surround/suspension—of different sizes. The larger 10 mm driver acts exclusively as a subwoofer handling sound from ~200 Hz and below only, with the smaller 7.8 mm driver catering to the rest of the audible frequency range.

I can’t find info about the material type of the diaphragms of the DUO’s two 7mm dynamic drivers, but in theory, they work in the same as the RED does, one DD for the lows, the second DD for the rest of the spectrum, for the mids and the treble.

Truthear ZERO RED vs CCA DUO Review
This is how CCA explains the working of two drivers

Both IEM’s sound character happens to be in line with the Harman 2019 v2 in-ear target, and that happens to be the goal with the tonality of these two sets.

Specs and box content


  • Driver: 10mm+7.8mm Dynamic Driver
  • Diaphragm: Polyurethane Suspension LCP Liquid Crystal Composite Diaphragm
  • Impedance: 17.5Ω±15% @1KHz
  • Sensitivity: 117.5dB/Vrms @1KHz
  • Price: $49


  • Driver: 7mm+7mm Dynamic Driver
  • Impedance: 18Ω±3dB @1KHz
  • Sensitivity: 106dB/Vrms @1KHz
  • Price: $30


Let me tell you how this kind of tuning sounds in general on both IEMs for a start. Later I will make my comments on how the little differences affect the overall sound on both IEMS.


Both have an elevated, impactful, and full-bodied bass reproduction. The sub-bass is slightly more prominent than the rest of the bass range, however, the bass feels abundant altogether. The textured and powerful bass contributes to the fun factor of the IEMs. The tuning prevents the bass from bleeding into the lower midsection. The detail level is also good. The bass is controlled, powerful, and quite exciting to listen to.

Starting with the lower mids, the sound follows a recipe of linearity. I would easily say that this smart move ensures that the signature stays airy and a general sense of air is present. The overall signature feels quite spacious, as well as the stage and the space between the instruments. The midrange has a linear tonality and features a note weight that is rather on the lighter side of the scale. However, the body of the instruments and the body of the vocals do not feel particularly thin and insufficient. The vocals feel breathy with plenty of details and they are quite engaging to listen to. The resolution and detail retrieval are really good, you can hear and track micro-details and individual instruments on the stage, easily. The slightly recessed midrange does not stick out at all, it feels quite alright, following the rest of the spectrum effortlessly.

The treble range follows the bass line, they are a little more pronounced compared to the lower midrange. The second dynamic driver does a good job of reproducing detailed, articulate, and clean treble. The resolution and detail level are certainly impressive for this price range and the extension is quite satisfactory. The dispersion of extended highs helps stereo imaging and enhances the perception of stage height and width.

Truthear Zero vs Zero Red

Let’s look at how Crin changed the tuning from the original ZERO to the ZERO RED. In the first edition, he tried to be as close to Harman’s target with a little bump on the mid-bass. Sadly that bump made the IEM a bit bassy for my taste, other than that I really liked the first ZERO, mainly because of its clear and detail-oriented sound. On most tracks, this tuning worked very well for me.

Coming to the second generation, the RED, we see that Crin changed the low and mid treble to his own curve, decreasing the values. We also see slightly reduced values on the upper midrange. From his perspective, this move makes sense because he is trying to replace the Harman tuning with his kind of tuning for the masses. He also tamed down the mid-bass and gave the sub-bass more presence which I find a smart move in the name of a more balanced sound, natural lovers like me. And for the bass lovers, he added a 10 Ohm adapter in the package. When plugged in you get around 3-4dB elevation on the lows. But for me, no thanks, too much bass for my taste with the adapter.

I also didn’t like the change on the treble, because for my taste it significantly reduced the detail retrieval and bright sound that prefer. I still like the original Zero more. But I get the idea, that this tuning is for the masses, and even if it’s not the right move for the overall sound sometimes.

Truthear ZERO RED vs CCA DUO Review

Let’s bring in the CCA DUO (blue graph) into the picture. The bass line almost follows the RED’s, slightly less (which is always welcome for me). The upper mids are on the exact same level as the original ZERO, which I also like as it brings some vocals and instruments a bit closer, with a crisper tone. Looking at the lower and mid-treble we see that the DUO reduces the 4-5K peak slightly, which helps to reduce the “bright” sound that some complain about on the ZERO. Meeting the curve around 6K and having better treble extension from there (after 8K) compared to both ZEROs.

CCA DUO’s tuning takes the mid-bass bump away from the ZERO on a polite bass line but keeps the extensions on the treble side which the RED lacks. This tuning makes the DUO more on the balanced-sounding side but with better clarity and detail retrieval, at least if you are using a good source. By the way, both IEMs are easy to drive but at least a dongle DAC is always preferable.

Truthear ZERO RED vs CCA DUO Review


The soundstage is one of the strong suits of both IEMs because of their 2-DD structure and tuning. The instruments have accurate positioning with ample space between them and you can easily track individual instruments on the stage. The 3D effect that the wide soundstage brings is there and definitely welcomed by the gamers. Also suits well with movies etc.


Depending on your tuning/sound taste we can easily say that both of the IEMs sound very good if we consider their prices. None of them may let you down when it comes to the sound performance. But in my book the CCA DUO takes the lead, because of its more suitable tuning for my taste, its way better ergonomics, and the $20 price difference.