Moondrop Chu II IEM Review

[Heinrich]

For consumer-oriented solutions, amongst others, I have in-depth experience with Mini, which relates to ...

"(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?

Thanks for the link, I'm looking forward to give it a try.

On the question, there are personal HRTFs for diffuse field, and I've seen those dips and peaks all the time. B&K published a paper on the acoustic impedance of the ear canal which shows the resonances clearly. Hence they must be seen in measurements of an IEM put onto the canal.

 

[oscar_dziki]

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.

Thank you!

 

[Heinrich]

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.

Sure, something like Idun may provide a solution. Mimi not that likely. I gave up on the latter, especially as it seem to address wide band hearing loss rather than fine grained specifics of a personal HRTF. The former is costly, if regularly available at all, and is clearly not considered when evaluating the Harman preference.

It's only anecdotal, but I tried to optimize my headphone experience with extra equalizing beyond just linearizing to whatever standard. Seems I prefer some extra dip at 10kHz on top of the headphone's a lot. Due to age I cannot comment on my preference above 12kHz. To me the sounds up there don't appear as an exact tone no more. At around the 3kHz bump I shift it a bit lower, tune it less pronounced and narrower.

In the end I'm not critizising. It is more curiosity, namely why the regular Joe doesn't feel the difference between the Harman preference opti versus a personalized fit. Seems it is less of an issue, because otherwise knowledgeable people would eagerly equalize accordingly. Conversely, if some deviation is readily acceptable, why so picky regarding the match to Harman? It all wonders me.

 

[CedarX]

In the end I'm not critizising. It is more curiosity, namely why the regular Joe doesn't feel the difference between the Harman preference opti versus a personalized fit. Seems it is less of an issue, because otherwise knowledgeable people would eagerly equalize accordingly. Conversely, if some deviation is readily acceptable, why so picky regarding the match to Harman? It all wonders me.

I EQ a lot… But I don’t think I have settled on a “personalized fit”:
1/ I easily get accustomed to a HP/IEM sound as long as it’s reasonably good.
2/ When EQ’ing, I usually end up with the following: I can hear the impact of a particular EQ filter… but, because of 1/, I’m not sure and can’t really say if it sounds “better”.

I’m most likely in the Harman “taste zone” referenced by @Maiky76 in their previous post, but I like the precise, picky, EQ to the Harman target as an anchor of what “good sound” sounds like for most—the highest preference score.

 

[Heinrich]

I EQ a lot… But I don’t think I have settled on a “personalized fit”:
1/ I easily get accustomed to a HP/IEM sound as long as it’s reasonably good.
2/ When EQ’ing, I usually end up with the following: I can hear the impact of a particular EQ filter… but, because of 1/, im not sure and can’t really say if it sounds “better”.

I’m most likely in the Harman “taste zone” referenced by @Maiky76 in their previous post, but I like the precise, picky, EQ to the Harman target as an anchor of what “good sound” sounds like for most—the highest preference score.

Thanks for picking this topic up and sharing your personal experience. It goes a bit beyond some commentary on a particular IEM. And sure enough, I seem to like the Harman also, but still I'm curious about further improvement. The how-to is the problem as long as I cannot identify my preferences (sic!) for one, and second the combinatorial explosion of all the possibilies considering their mutual dependencies. CU

 

[CedarX]

Thanks for picking this topic up and sharing your personal experience. It goes a bit beyond some commentary on a particular IEM. And sure enough, I seem to like the Harman also, but still I'm curious about further improvement. The how-to is the problem as long as I cannot identify my preferences (sic!) for one, and second the combinatorial explosion of all the possibilies considering their mutual dependencies. CU

Agreed on the difficulty of the "how-to"! I like @Maiky76 and Amir approach to limit the number of filters--3 or 4 filters that I can "evaluate" individually: what is the audible effect of filter #1? Do I seem to prefer the resulting sound? What about "exploring around" (varying freq., gain, Q-factor)? If an IEM has some significant deviation from the Harman target as-is, is there anything I like in the FR?

Another interesting tool that could help with the "how-to" is MSEB, HiBy's "pre-baked, typical, PEQ filters" (see @Jeromeof MSEB EQ measurements in his R1 review at https://www.pragmaticaudio.com/reviews/2025/02/hiby-r1/). What MSEB does is to provide basic "words" that could be used to characterize a PEQ correction or the HP/IEM FR curve as compared to the target. One could express his/her preferences against the Harman target in unified "MSEB language", for example,: I like a "2dB warm temperature tilt, a -1.5dB vocal recessed, and +3dB air crisp" over the Harman target.

 

[XaviMartinez55]

Warning: Totally uneducated, unempyrical and subjective impression on the Chu II...

Got the Chu II 2 weeks ago and had it for a few days before I returned it......too peaky for me and not enough bass (I tried different ear tips to no avail) .

I received the week after the Ziigaat Nuo -after viewing tons of Squiglink curves- and to me it corrects everything I didn't like about the Chu II. More bass extension, still a bit peaky on the 10-12 kHz (but less), louder, and reacts very well to eq.

I may be a bass head and not even be aware of it -I'm a total noob to iem addiction syndrome- , so I am waiting for a Kz Castor Pro Bass and a Kinera Celest Wyvern Abyss, curious about what s basshead iem is....