TRUTHEAR x Crinacle Zero:BLUE2 IEM Review

[amirm]

This is a review, listening tests, EQ and detailed measurements of TRUTHEAR x Crinacle Zero:BLUE2 in-ear monitor. Crinicale sent it me and costs US $64.95. Option exists for adding a cable with microphone.

While personally I don't want to see any color in my IEM, the understated blue texture is fine. Two sets of tips are provided: silicon and foam. The largest silicone fit me well. The largest foam is too small and at any rate, easily compresses to nothing so didn't work for me. I did measure it though as Crin says its frequency response is tuned for compliance using that tip.

A "bass boost" adapter is provided for 5 dB increase. This being a passive device, it can't amplify that region. Instead, it attenuates the rest. So you give up good bit of sensitivity for that extra boost.

If you are not familiar with my headphone measurements, I highly recommend to watch my tutorial on it:

[And subscribe to the channel ]

TRUTHEAR x Crinacle Zero:BLUE2 Measurements
As usual, we start with our frequency response measurement, with and without bass boost, using my preferred silicone tip:

Compliance is very good with extra bass below 70 Hz and some peaking between 3 and 8 kHz.
The dashed brown line shows the impact of bass boost adapter (which is just a 5 ohm resistor) after I boosted the volume to match my reference. Interesting that it gives you the bass boost but also reduces the peaking in highs. Given the bass response we already have, I don't see the reason to use this adapter anyway.

The effect of foam tip is much harder to measure as reinsertion with a new tip can completely throw off how the IEM was fitting before (or conversely, make it better). But here it is anyway:

I am seeing a bit less bass boost so that part matches the target better. But then there is more highs which is the inverse of what we are supposed to see. As far as I am concerned, all of these all in the category of measurement error so I wouldn't draw any hard conclusions from it one way or the other.

The mechanical fit to the artificial ear must have been better with the foam tip as the "rocking mode" around 110 Hz has disappeared.

Going with my preferred silicone tip, the differential to our target is very small:

I put the right cursor where one may want to dial in a negative filter. Shape lends itself well to typical response of a PEQ filter. Above that, it is a no man's land as far as measurement accuracy even though Crin talks about changes in that region.

I was disappointed to see higher distortion in mid frequencies than other iterations of this iEM:

We have around the same distortion at 94 dBSPL as we do at 114 dBSPL with other IEMs. Bass distortion is very how however.

Group delay is clean as I expect it to be:

Impedance is highly variable which explains why addition of a simple 5 ohm resistor changes the frequency response:

This also tells you that you must not use a headphone amplifier source with non-zero output impedance which includes many Receivers and computers.

Another reason to use a proper adapter is rather low sensitive for an IEM:

TRUTHEAR x Crinacle Zero:BLUE2 IEM Listening Tests
I started my listening tests with the foam tip. I found bass response to be lacking. Cupping my hands over each ear substantially improved that, telling there was air leakage. I replaced the tips with largest silicone which made an incredible difference, producing some of the best bass response I have heard in an IEM. It is deep, thundering and extended (within what an IEM can do). The highs seemed glorious at first but then started to sound a bit bright. So I dialed in a single filter:

The trade off was exactly as you would expect: the sound became more balanced and less bright. But you lost some of that airiness up top. As much as I am a fan of the latter, I chose to listen with the filter in place and concluded I like it better this way. To me anyway, the measurements are correct here, indicating excess treble energy. Tiny amount as it might be.

I spent some time with the filter listening to my reference tracks. Smile was stuck on my face the whole time. The fidelity is stunningly good with a level of uncanny detail and broad spectrum cleanliness that you only experience with ah proper IEM.

Conclusions
We now have half a dozen variety of these near-target IEMs. I suspect you all look to me to tell you what is the difference between them. I can't do that. We are within measurement errors of our target and audience preference. If I were to give you definitive feedback, it would need to be in a controlled test with quick switching which is not practical with IEMs. So the job here is to filter all the choices down to a few and have you experiment to pick one. Personally I would choose any of them and apply the bit of filtering needed to match my idea of neutrality.

I am happy to recommend the TRUTHEAR x Crinacle Zero:BLUE2. Another job well done.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[raif71]

Waiting for mine close to a month now (preorder)

 

[phoenixdogfan]

Great review, Amir. Thank you.

Personally, I don't know why Crinacle released this one. He already has the original Blue which followed the Harman Target about as closely as anything that was released previous to it, and he has the Red which more closely mirrors his own preferred Meta tuning. The only thing I see as different between this and the OG is the inclusion of the impedance adaptor which lowers everything except the output of the bass driver, thereby making the bass more prominent. And the distortion numbers are worse than the original Blue!!! And people who had problems with nozzle diameter, will still, no doubt, continue to have problems with this iteration.

Maybe Crin should have given a little more thought into a rethinking of this model instead of branching out into reviewing fast food fried chicken. After all, we already have Review Braugh for that job.

 

[amirm]

After all, we already have Review Braugh for that job.

Review Brah is so good at it.

 

[NoteMakoti]

And people who had problems with nozzle diameter, will still, no doubt, continue to have problems with this iteration.

Gonna say personally, after trying this one, it's much more comfortable than the original Blue. It's probably the only reason I'd consider sidegrading at all.

 

[johny_2000]

It seems odd that their own distortion measurements differ in the midrange, although there is no indication at what SPL they were taken.
Their specs say THD <0.3% @1kHz @94db

 

[GeekyBastard]

I don't see the reason people should be choosing this instead of the Truthear Zero Red, not much of an improvement, with even worse distortion.

 

[amirm]

The 5128 fixture's microphones have higher distortion than the one in my GRAS 45CA (smaller diameters). So maybe that is what they used and hence the reason they didn't see the distortion rise there. And as you say, you need to have high enough playback level to see these distortions over noise.

 

[Maiky76]

Here are some thoughts about the EQ.
Please report your findings, positive or negative!

Notes about the EQ design:

• The average L/R is used to calculate the score.
• The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
• A Genetic Algorithm is used to optimize the EQ.
• The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve (and other constraints) with a fixed complexity.
  This will avoid weird results if one only optimizes for the Score, start your journey here or there.
  There is a presentation by S. Olive here.
  It will probably flatten the Error regression doing so, the tonal balance should be therefore more neutral.
• The EQs are starting point and may require tuning (certainly at LF and maybe at HF).
• The range around and above 10kHz is usually not EQed unless smooth enough to do so.
• I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
• With some HP/amp combo, the boosts and preamp gain (loss of Dynamic range) need to be carefully considered to avoid issues with, amongst other things, too low a Max SPL or damaging your device. You have beed warned.
• Not all units of the same product are made equal. The EQ is based on the measurements of a single unit. YMMV with regard to the very unit you are trying this EQ on.
• I sometimes use variations of the Harman curve for some reasons. See rational here and here
• NOTE: the score then calculated is not comparable to the scores derived from the default Harman target curve if not otherwise noted.
• Occluding IE devices generally must have very good fitting/seal in the user's ear canal for best performance.
  please spend a few minutes to pick up the best ear tip... Be sure to perform this step otherwise the FR/Score/EQ presented here are just worthless.
• 1. more bass = better seal
  2. More isolation from the outside world = better fit
  3. Comfort

Good L/R match.

I have generated one EQ, the APO config file is attached.

Score no EQ: 84.1%
Score Amirm: 84.5%
Score with EQ: 96.7%

Zen Blue IEF Full EQ
April112025-140708

Preamp: -4.00 dB

Filter 1: ON PK Fc 17.7 Hz Gain -3.62 dB Q 0.33
Filter 2: ON PK Fc 1355.4 Hz Gain -2.07 dB Q 0.88
Filter 3: ON PK Fc 2464.0 Hz Gain 1.48 dB Q 2.54
Filter 4: ON PK Fc 4663.6 Hz Gain -2.90 dB Q 1.38
Filter 5: ON PK Fc 10549.4 Hz Gain 7.29 dB Q 2.50
Filter 6: ON PK Fc 16363.6 Hz Gain -13.61 dB Q 1.84

 

[Andreas007]

Maybe it's time to buy 10 of the same type and compare their distortion profile to each other?

 

[RogerSmith]

What a nasty peak at around 12k. Also too bright at the ear gain region. I see no reason to get this in 2025, there are either cheaper options (Gate, Salnotes Zero 2), or much better ones with smoother treble (Nova,..). Even the Zero Red is better.

 

[Grobbelboy]

Nice to see a review of this one so quickly, thanks @amirm.

The reason I had an interest in this was for the potential of it being more or less perfectly tuned out of the box, but alas. That slightly too elevated treble seems to be ruining things. Truthear Nova remains the better (and perhaps only) choice in that regard.

 

[gvl]

What is the significance of “Zero” as it’s used in the naming by different brands? Same for Crinacle but I think I figured out that part, he’s a tuner who works with these shops.

 

[raif71]

What is the significance of “Zero” as it’s used in the naming by different brands? Same for Crinacle but I think I figured out that part, he’s a tuner who works with these shops.

Perhaps have something to do with an Anime series ?

 

[heraldo_jones]

What a nasty peak at around 12k. Also too bright at the ear gain region. I see no reason to get this in 2025, there are either cheaper options (Gate, Salnotes Zero 2), or much better ones with smoother treble (Nova,..). Even the Zero Red is better.

According to Crinacle this iem was designed to be used with foam tips in specific (so a no no for me). Sadly I don't know why the distortion levels are so high, in fact Crinacle said they were even lower than in first iterations.

 

[oozlum]

Nice to see a review of this one so quickly, thanks @amirm.

The reason I had an interest in this was for the potential of it being more or less perfectly tuned out of the box, but alas. That slightly too elevated treble seems to be ruining things. Truthear Nova remains the better (and perhaps only) choice in that regard.

Truthear Hola ?

 

[192kbps]

If Harman's 5128 target curve is eventually released, will it be significantly different from the current one? This has caused me noticeable concern.

 

[daniboun]

Nice IEM not as good as the Truthear GATE IEM
Thx Amir for the review

 

[thewas]

If Harman's 5128 target curve is eventually released, will it be significantly different from the current one? This has caused me noticeable concern.

Depends how someone defines significant and which one you mean as current, I wouldn't be surprised if there will be some evolution like also in the past, see also this recent paper from Sean Olive if its not known to you yet
https://aes2.org/publications/elibrary-page/?id=22696
(currently free to download)

 

[alekksander]

even more shout? no thanks.