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Moondrop Chu II IEM Review

Rate this IEM:

  • 1. Poor (headless panther)

    Votes: 1 0.4%
  • 2. Not terrible (postman panther)

    Votes: 5 2.1%
  • 3. Fine (happy panther)

    Votes: 35 14.6%
  • 4. Great (golfing panther)

    Votes: 199 82.9%

  • Total voters
    240
This sort of argument always comes across to me as audio nihilism. Effectively "everything is guesswork so why draw any conclusions at all."
Constants exist and they're not infinitely imprecise. It's not the exactitude many would wish for but I think that's well-acknowledged.
My issue is with people suggesting that because it's imprecise we should invalidate formal conclusions altogether. It reads as curtailment of objectivity to the benefit of those who are a little miffed that their favorite headphone rated poorly.
More like healthy skepticism from understanding that biometric uncertainty is something the measurement apparatus can't predict. Within that frame of reference it's still rational to question an IEM based on measurements, especially if it's pricey. Slamming OTOH is closer to megalomania on behalf the measurement equipment or something like that.
 
So if an OEM produces an IEM with any random FR measurement, I should now refrain to “slam” it and accept it “as good” as any other IEM? I would consider it if the OEM explains which user group they target and present supporting evidence as why their IEM is delivering for that group…
They never do…

If I change my mindset as you recommend, any IEM FR is acceptable. How is it helpful?

The review criteria may be imperfect, but I don’t think the strategy is flawed: even with these latest results, Harman is still a target that would be among the preferred ones for the largest group of users.
I said "Lots of people here slam more expensive IEMs just because they are not as similar to Harman as some of the cheap ones measured here." This by no means suggests that I think any FR is good. What I have been saying is that Harman is no longer the only scientifically optimized target we have. There are other competing targets that are equally well preferred. One shouldn't use Harman compliance as the only way to evaluation the FR of an IEM. For example, IEM A could be less similar to Harman than IEM B, but it might also be more similar to soundguys' target and is definitely not necessarily a worse IEM.
 
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Are you suggesting that the research is flawed because it reflects badly on expensive products?


The targets you mentioned aren't drastically different to Harman and IEMs are usually slammed here for being way off the mark. A bunch of similar targets being similarly preferable doesn't negate that they're all a good basis for audio that will please most people.
Sure, there's more to audio than a target but we all know that. FR targets are the best objective guides we have right now. "Not good enough" implies a "better," which in this case doesn't exist.
No, the methodology is flawed because it compares too few targets, and this is a flaw that is very difficult to overcome. Lots of more expensive IEMs are tuned to the Harman target (EM10, Variations, Glacier, Xenns Top, IO Sogno/Volare, etc), so this has nothing to do with price.

I have been saying that "they are all a good basis for what will please most people", and so the mindset of many in forum (that Harman is the only standard and that if an IEM is less similar to Harman than another, all else equal, it is worse) is inappropriate.

I actually don't think there is much more to audio (especially IEMs) other than FR at the eardrum. However, my opinion is that there are many FR targets that are appreciable and worthy of producing and listening to (or at least trying out). This is simply because not all the people have the "average anatomy" and "average taste"; the optimum for the entire population across music recordings might not be the optimum for a particular individual and the specific music that they listen to. Even for some one with the average anatomy and average taste, they might occasionally want to hear something that is different.

Also notice that Harman is actually the more "extreme" targets in the best bunch. It has the most 3k-8khz energy (IEMs that clearly try to tune to Harman usually have less of this region) and the least midbass energy (likewise, most IEMs that are tuned to Harman have slightly more midbass). It is very likely, not the dead-average among the best targets. Likely because of this, the Harman is at the moment quite polarizing outside of this community.
 
Bad construction. After 6 months I don’t know what happened but the right side stopped to work properly. The problem seems the filter. Is may be clogged but even after carefull cleaning it doesn’t work properly. If they think I will be a slave bying 10€ filter each 6 months I will not be that slave.
 
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Bad construction. After 6 months I don’t know what happened but the right side stopped to work properly. The problem seems the filter. Is may be clogged but even after carefull cleaning it doesn’t work properly. If they think I will be a slave bying 10€ filter each 6 months I will not be that slave.

Is condensation because of the metal shell it can happen to any alloy IEM with some cleaning the filter or waiting for it to evaporate works with others you'll need new filters.

It happened to mine the same day I got them, the second pair of filters is still working properly but I stopped using the IEM after 6-7 months and just use them sporadically now, filters are $4.99, when I ordered mine about a year and a half ago they sent me 10 pairs.

Look for the Chu II and choose the "filter only" option.
 
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Read another review and I feel like I need another set of IEMS LOL. Do the Chu IIs come with the Moondrop spring tips?? I was searching for those, and a post lead me back here saying for just a few dollars more, I can get the spring tips along with a nice set of IEMS :D
 
Read another review and I feel like I need another set of IEMS LOL. Do the Chu IIs come with the Moondrop spring tips?? I was searching for those, and a post lead me back here saying for just a few dollars more, I can get the spring tips along with a nice set of IEMS :D
No they don't . The Chu mk 1 did
 
No they don't . The Chu mk 1 did


Okay .... nevermind then. Probably won't use these much now that I purchased the Moondrop Dusks. I have problems with fits, so I've never really tried IEMs. But now I see there are many options for tips (never like the Comply tips) including Azla, TRI Clarions and the Moondrop Springs. Thanks.
 
now with Moondrop FreeDSP DAC/Cable and Moondrop EQ Settings + Kbear07 Ear-Tips the Chu II sounds decent
 
Voted great after testing them.
Had to rise the volume from 40 to 55 on
my Fantom 8 to get the "same sensations".

Frankly, I am not able to say with utmost
clarity if I prefer them over the Zero 2...

Time will tell, just went testing for some twenty minutes.
 
Got a set this week. Boy, do they ever provide great resolution of the sonic field! Mind-blowing, at times. That said, I've gotten spoiled by having a bit more mid-bass in the mix. Although these little wonders go VERY low, perhaps close to 20 hz. But I love their clarity and 3D view into the recording. Vocals are in the room with you! Haven't tried EQ yet. I ordered the spring tips to try to see what they will do to tame that hi-freq edge, but what a little marvel these are! Running from also just received EverSolo Z-8 DAC, which drives them very well.
 
Amazing set, with some EQ they sound way too good for this price. Lovely treble extension compared to the Zero 2s. Anyway in these days if you don't EQ an IEM what's the hole point of them, JA11/JM12 are perfect and cheap solutions. Can't believe with 19$ IEM and 8$ dongle you can reach such quality and clarity it's insane, probably there is a bit left with proper tips too.

Preamp: -2.9 dB
Filter 1: ON PK Fc 170 Hz Gain -2.3 dB Q 1.700
Filter 2: ON PK Fc 490 Hz Gain 2.0 dB Q 0.800
Filter 3: ON PK Fc 4200 Hz Gain -1.9 dB Q 1.200
Filter 4: ON PK Fc 12050 Hz Gain -6.0 dB Q 6.000
Filter 5: ON PK Fc 16500 Hz Gain 3.0 dB Q 1.000
 

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What means OTT and knowles in this context?
Over The Top or overkilled:
The second EQ (OTT), designed around the Harman target, includes three additional Biquads but provides only a slight improvement in the overall score.
 
Here are some thoughts about the EQ.
Please report your findings, positive or negative!
...
Score no EQ: 84.1%
Score Amirm: 89.2%
Score with EQ: 93.2%
...
OTT version for comparison:
I was under the impression that the preference score is a predicator for how much the market is going to like the product in comparison to a contender. It aims to maximize on average the individual person's willingness to pay and keep the product over the other. As far as I was told a difference between 80% and 95% is provided, but it is only due to rank; the bigger or lesser difference doesn't make sense as a distance. (see: https://www.statology.org/levels-of-measurement-nominal-ordinal-interval-and-ratio/). We are on an 'ordinal' scale. You don't say otherwise, whilst handing out quite accurate numbers. That said only for clarity.

A more crucial question came to mind. The Harman is a curve again addressing preference on average. It is smoothed and generalized so much, that must-be-there features are suppressed. In short, because it addresses the average, the Harman is decidedly an optimum for no one. It is always more or less wrong because people have different head and ear shapes besides just taste. Do you agree?

If (not) so, what about finding a personal preference to be exact? (A) There could be an optimization for the 3kHz region. The amplification maximum could be at a different frequency, the amplitude be different, and its sharp or broad shape may differ (objectively) for individual people.
(B) Same with the 10kHz trough, which is told to be a must btw, and the 14kHz something peak, again a must.

Did you ever try to identify your optimum by preference, after miticulously (OTT as you say) equalizing the IEM to Harman as a starting point? Leave all corrections in for Harman, and then find a deviation that fits your hearing the most by setting additional filters?
 
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I was under the impression that the preference score is a predicator for how much the market is going to like the product in comparison to a contender. It aims to maximize on average the individual person's willingness to pay and keep the product over the other. As far as I was told a difference between 80% and 95% is provided, but it is only due to rank; the bigger or lesser difference doesn't make sense as a distance. (see: https://www.statology.org/levels-of-measurement-nominal-ordinal-interval-and-ratio/). We are on an 'ordinal' scale. You don't say otherwise, whilst handing out quite accurate numbers. That said only for clarity.

A more crucial question came to mind. The Harman is a curve again addressing preference on average. It is smoothed and generalized so much, that must-be-there features are suppressed. In short, because it addresses the average, the Harman is decidedly an optimum for no one. It is always more or less wrong because people have different head and ear shapes besides just taste. Do you agree?

If (not) so, what about finding a personal preference to be exact? (A) There could be an optimization for the 3kHz region. The amplification maximum could be at a different frequency, the amplitude be different, and its sharp or broad shape may differ (objectively) for individual people.
(B) Same with the 10kHz trough, which is told to be a must btw, and the 14kHz something peak, again a must.

Did you ever try to identify your optimum by preference, after miticulously (OTT as you say) equalizing the IEM to Harman as a starting point? Leave all corrections in for Harman, and then find a deviation that fits your hearing the most by setting additional filters?
I suggest you read the links in the preamble of my EQs.
[...]
  • 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.
  • The EQs are starting point and may require tuning (certainly at LF and maybe at HF).
  • I sometimes use variations of the Harman curve for some reasons. See rational here and here
[...]

Apologies for the tone of the to last links but there is some information.
Some quotes:

[...] Nov 2021

This study, demonstrated according to S. Olive that:
•A 64% (the majority) of listeners prefers headphones with a frequency response that adheres to the Harman Target Curve.
•A 15% portion of listeners prefers 3 to 6dB more bass, usually younger males and less experienced listeners.
•A 22% portion of listeners prefers 2 to 4dB less bass usually older population, and biased towards females.

Based on this data one can roughly derive preference range, neutral being the default Harman curve:
•-3dB/Neutral/+3dB/+6dB as EQ for bass preference;
•-1.5dB/Neutral/+1.5dB for as EQ for treble preference;

That means that you can still be within the “taste zone” of the Harman target while not being completely on the “majority” curve.
You just change the likelihood of the EQ to be optimal for the user, but still rather close to it...
A number of people will actually prefer that, it's also a major piece of knowledge that is often ignored.
A marketing department might even tailor the default curve to cater best for a certain audience…

@amirm is probably +3dB@LF -1.5dB@HF as I have already casually observed, but the listening material also have an influence…
Again these EQ are starting point as clearly stated, for about a third of the population it is not the ideal curve...

The map and the country, or if you prefer, model vs reality.
The users must not comply with the target but the target can be adjusted to the user.
All the models are good approximations so most probably, in the details, every user has his/her own slightly different preference target.
Again from the study at least a third of the population exhibits significant deviation from the default target.
The whole "taste zone" is the "Harman target curve" for the complete population (with "normal hearing").
It may not matter if we are only ranking devices against each other (although it may, see hereafter) but it will matter when trying to EQ to the exact target. Readers need to understand that and I wrote it in my EQ preamble.

As a matter of fact, to me, one of the greatest outcomes of the study is that yes, differences exists between users but they are quantifiable and trends are clear to be seen.

How long before AIs will automatically adjust the EQ based on the material been listened to and your Facebook account?
Note that measurements for physical (anatomic, fitting etc.) variations is very much possible already (otoacoustic emissions and self/adaptive EQing products)
[...]

My preference is basically on the average target, with maybe a tad less HF.

As quoted I have devised a simple strategy to get even closer:
Based on this data one can roughly derive preference range, neutral being the default Harman curve:
•-3dB/Neutral/+3dB/+6dB as EQ for bass preference;
•-1.5dB/Neutral/+1.5dB for as EQ for treble preference;

So the base EQ (or OTT) + two shelves + a lot of blind A/B listing = very close to your ideal curve.

That all you can safely conclude from the available results. Finer or larger adjustment may be related to outliers or subject with abnormal audition.

"(B) Same with the 10kHz trough, which is told to be a must btw, and the 14kHz something peak, again a must."
Do you have hard evidence for that, in in particular in an IEM?
 
I suggest you read the links in the preamble of my EQs.
I did already of course. But did you ever try to equalize to your personal physiology (objectively) and taste (subjectively) combined? What was the algorithm in setting the filters?
 
I did already of course. But did you ever try to equalize to your personal physiology (objectively) and taste (subjectively) combined? What was the algorithm in setting the filters?

I have extensive experience with various "objective strategies," including lab-grade testing.

For consumer-oriented solutions, amongst others, I have in-depth experience with Mini, which relates to Pure Tone Audiometry, as well as Nura/Denon/Masimo, which utilize otoacoustic emissions. These approaches already surpass Apple's offerings by a significant margin IMO.

If we consider HRTFs as part of the physiology, I’ve had mine measured multiple times and even programmed a DSP with it for spatial audio.
That's a whole new discussion I won’t get into but on the consumer side, Idun is a solid option.

It’s possible to stack "objective" EQ with "preference" EQ (as described in the previous post), but one must be aware that after applying the "objective" EQ, the new "preference" EQ may require adjustments. This is because the original "preference" EQ may have included elements of the "objective" EQ.

To use an analogy, suppose someone needs to boost green (HF) significantly on a calibrated screen (Harman default curve on earbuds) due to a measurable physiological condition. That person might not realize they are blending preference with objective compensation.
Now, if they start wearing glasses that correct their physiological issue (similar to how Mimi Hearing Test compensates for hearing loss) while still using a properly calibrated screen (Harman default curve), they may still need to adjust the green (HF) to their liking but in a different way than before.

My ears are still good enough to not require a specific physiological compensation and as I stated I am more or less Mr Lambda.

BTW, to be statistically ranked two EQ/devices need to be 8-10 score points apart AFAIR so it is better that just ordinal, I would think.

Question still pending...

"(B) Same with the 10kHz trough, which is told to be a must btw, and the 14kHz something peak, again a must."
Do you have hard evidence in general for that, or in particular in an IEM?
 
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