It seems you just have the wrong version: the 3.5mm Chu-II coupled with any decent (inexpensive) dongle would better suits what you’re looking for.
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Digital equalization has no phase shift problems: for FIR filters the phase response is linear.
It is possible to create a zero-shift digital filters:
Passive filters do not have linear phase and are subject to phase shift problems.
A 12dB/oct two-way LC crossover filter has a 180° phase shift between tweeter and woofer and requires inverting the polarity of one of the drivers to avoid destructive interference at the crossover frequency.
One of the advantages of active speakers with separate amplification for the drivers and digital input is precisely that of avoiding having passive crossovers with the problems that they entail (phase shift, power absorption, saturation and hysteresis of the magnetic cores of the inductors etc.).
Obviously passive speakers cannot but have passive filters and therefore the problems that passive filters entail are accepted because there is no alternative: however, no one says that the problems do not exist.
What kind of crossover filter do the Te Zero:RED have? A capacitor in series with the tweeter? An inductor in series with the woofer? What happens at the crossover frequency? What are the phase shifts between the drivers at the crossover frequency?
So I think that objectively, at the same performance, an IEM with a single driver is better. Two or more drivers are only needed if one driver alone cannot do the same thing.
I think anyone can see that the Chu II are less bulky than the TruthEar Zero:RED and the 7Hz Zero:2.
Regarding comfort, you are the first one I hear that considers the TruthEar Zero:RED more comfortable than both the 7Hz Zero:2 and the Chu II.
Personally, I can only tolerate the Zero:RED with the memory foam pads, otherwise I can't wear them for more than an hour.
Unfortunately, the foam pads are very delicate and don't last long, they are difficult to clean and sanitize and it takes some care to wear them correctly.
They also change the frequency response of the measurement published by ASR.
The DSP version of the Chu II is interesting for two reasons:
- cost: they are the least expensive hi-res solution that exists
- simplicity: you don't have to carry around lots of cables, external DACs and other things that weigh, take up space, complicate your life and risk damaging the connectors of your phone, DAC, etc.
With the non-DSP Chu II I don't use the 3.5mm connector because I can't get the separation between the channels that I want. I use a 4.4mm balanced cable and E1DA #9038SG3 or Tanchjm Space Dual or Tanchjim Luna (better). Only in this way can you not hear one channel in the other.
My interest in the Moondrop Chu II DSP is due to the fact that I can give them as gifts to friends and acquaintances for the Christmas holidays.
They have a ridiculous cost and allow incredible performance with music and, if they worked, they would also be very convenient for making phone calls.
These ideas are often repeated online but are misunderstood topics that lead to erroneous conclusions. It seems you prepared a counter-argument prematurely, so I can't tell if you are willing to learn why these statements have errors.
Digital filters come in minimum-phase or linear-phase, whereas analog filters come only in minimum-phase. When using minimum-phase filters, any corrective EQ applied will also help correct phase issues in the same step. This is because the phase response of a minimum-phase filter is inherently linked to its magnitude response. This is valid for audio transducers, which basically make up a minimum-phase system. Minimum-phase filters(analog) are not inherently problematic with regard to phase relationships. Linear-phase filters are more problematic and field experts like Oratory1990 are skeptical of their use for audio.
Here's an audio example that highlights the pre-ringing artifacts of linear-phase filters used on audio content
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In your previous posts, you indicated that Chu-II DSP does work for phone calls, but stop working (for phone calls) after you play something with UAPP.
Do all your friends and acquaintances use UAPP on their phone to listen to listen to anything other than phone calls?
If they are that audio-savvy, gifting them something as cheap as Chu-II may offend them…
Just a thought
I actually said that with my current phone (Samsung S22) they never work to make a phone call.In your previous posts, you indicated that Chu-II DSP does work for phone calls, but stop working (for phone calls) after you play something with UAPP.
Do all your friends and acquaintances use UAPP on their phone to listen to listen to anything other than phone calls?
If they are that audio-savvy, gifting them something as cheap as Chu-II may offend them…
Just a thought
My post was inserted to know if others have the same problem: I saw "Eary's" post and it seems to me that there is the same problem or a very similar problem.
With other phones that I have tried, what happens is that if you use the Chu II DSP to listen to audio tracks with a resolution higher than 48/16, then they no longer work to make phone calls. I needed to know if anyone can use them to listen to hi-res music and make phone calls without problems.
All my friends who listen to hi-res music with their phone use UAPP: it is a very popular App.
Those who do not use it yet, can afford to spend $8 to try listening to hi-res music and see if they notice the difference and are interested in this new experience.
Luckily my friends do not evaluate things based on cost, but on their quality.
Logic that I believe is also quite the basis of the entire Audio Science Review site, which is why I visit it often.
Furthermore, it is then a small thought on the occasion of a dinner to say goodbye before the Christmas holidays.
Finally, when they work, you understand that they are of excellent quality even just for making phone calls, listening to non-hi-res music or watching a film on the phone.
Luckily on PC they work perfectly and allow you to listen to hi-res music and make excellent quality calls.
Since the invention of the Williamson amplifier (1947?), it has been said that linear phase filters are the best for audio: only now that the DAC reconstruction filters have a non-zero energy content before the pulse does it seem that everything depends only on "preringing".
Personally, I started hearing about this when Neil Young launched the Pono player on the market: it seemed that the presence of a minimum phase reconstructor filter designed by Ayre Acoustics was to be the great innovation capable of guaranteeing the maximum listening quality precisely because it was not subject to "preringing". The test of the Amirm Pono player does not seem to give reason to this theory.
Please try to connect a tweeter w/o inverting the polarity with a two way 12dB/oct crossover and listen...
Wrong: Bessel filters are analog and linear.
Another thing: in one of my previous posts I reported the link to digital "zero-phase" filters: therefore linear and minimum phase at the same time.
If you want I can list dozens of audio experts who claim the opposite.
Sorry, but I can't understand what are the difference: I'm convinced that there must be a difference (even if not in favor of minimum phase filters), but the video example doesn't highlight it (at least for me). What should I notice as a difference? I hear an audio track that is probably already very compressed with loss of information that without filters sounds quite decent and that with all the filters tried is massacred in the same way. Do I know what I need to focus on to find the difference?
N.B.: When I see the input signal of a non-linear phase device on my oscilloscope on trace A and how it appears on its output on trace B, it makes me want to cry...
In conclusion:
- I just said that an IEM with a single driver that has the same THD and the same frequency response as an IEM that has two or more drivers is better because there are no interference problems between the drivers and with the filters (and I would say that all this discussion about linear and minimum phase filters should lead to the conclusion that if you can, it is better to avoid having filters).
- It calls into question the gift of a small gift to friends and the quality of my friends.
- I just need to know if anyone can make the Chu II work for what they are intended for: to be used up to 96/24 and to make phone calls (otherwise explain to me why they have the microphone and a DAC that can work up to 96/24).
Do you have a schematic? One schematic for Truthear Red would also be useful if you want to discuss that IEM in an unbiased way.
I don't have a schematic (I think it's confidential data owned by TruthEar).
I had seen some pictures of the inside of the Zero:RED online, but I can't find them anymore.
What I can see through the transparent case with a fairly powerful flashlight doesn't show any inductors.
If a 12dB/oct two-way filter was planned, there should be at least two inductors that with a driver impedance of only 17 ohms shouldn't be very small and easy to hide.
Whatever crossover filter is used, the fact remains that for the same performance (in my opinion, but it's a fairly logical opinion) a IEM with a single driver is less complicated than one with two drivers and is subject to fewer problems.
I see no logical reason to think otherwise.
It's the reason that in all the past years has led many speaker manufacturers to try to make speakers with a single driver (Acoustat, Quad, Magneplanar, Tannoy, etc.): no interference between drivers, no filter problems, etc.
But getting back to the real question, I needed to know if anyone has tried the Chu II DSP for making phone calls with recent phones, or for making phone calls with any phone after pushing the earphones to 96/24 or 88.2/24 (with a player that doesn't downsample everything to 48/16).
Too many assumptions to make a generalization like that. Given that Amir evaluated it and didn't detect any issues leads me to think that the implementation is fine, and it's reasonable to expect it to be given how common dual-driver setups are, and the engineers and collaborator involved vetting it.
Why do you need 96kHz output?
Shame the app is so buggy. Always crashing or freezing, not updating the selected profile, losing connection with the earphones, entailing a force close and multiple removals and re-insertions of the USB-C connector to try and get a profile applied.
Please tell me how you make an inductor without a ferromagnetic core (otherwise you run into hysteresis and saturation problems) for a filter that has to drive drivers (at least one) of 17 ohm that can be inserted in an earphone the size of the Zero:RED. If you can do it, then my assumptions are generalizations...
In any case, I can't understand: I started my posts asking if anyone can make these IEMs work in all the modes for which they are designed and I feel like I need to pass an exam to understand if I can ask other users if they have managed to use them or if they have problems like I do.
Note that with my current Samsung S22, it is impossible to use them for a phone call no matter what you do.
Now I am asked why I would want a DAC that can work at 96/24 to work at 96/24: because otherwise I would have bought a DAC at 44.1/16 or 48/16...
90% of my tracks are 88.2/24 or 96/24 and I don't want to hear them downsampled.
Amirm does a test with a single sine wave that varies in frequency and detects the THD and the amplitude response of the earphones.
These are necessary but not sufficient conditions to know if a device reproduces the sound correctly.
Otherwise, why does he test DACs and amplifiers with two frequencies to detect intermodulation distortion or multitone behavior, if a graph of frequency response of amplitude and one of THD as a function of frequency were sufficient to test an audio system?
Please tell me what is the advantage of using two drivers instead of one with equal performance: I would like to understand...
Finally, if you ask me why I need to use 96/24, I ask you why audio technology did not stop at CDs...
Too many non-sequiturs, and premature counters to points I didn't make. I can't adress that in a reasonable way. But if hi-res audio something you feel strongly about you might feel out of place on ASR. If you have some practical issue that hi-res audio solves for you will gladly assist with finding some sort of solution. That's why I asked, but this seems not be the case.
Too many non-sequiturs, and premature counters to points I didn't make. I can't adress that in a reasonable way. But if hi-res audio something you feel strongly about you might feel out of place on ASR. If you have some practical issue that hi-res audio solves for you will gladly assist with finding some sort of solution. That's why I asked, but this seems not be the case.
Honestly, I have not seen anything similar among the ASR tests that is better.
In this case, the performance, cost and ease of use are very interesting.
The problem is that using the Moondrop Chu II DSP with all the phones I have tried (about ten by now) you lose the ability to use the phone if you use USB Audio Player Pro and with the Samsung S22 the phone no longer works at all because it can only play music tracks (even uninstalling UAPP): you can no longer make or receive calls.
You asked me if I had the ThruthEar x Crinacle Zero:RED filter schematic to understand if an IEM with two drivers is better or worse than one with the same frequency response and THD and only one driver: what filter would you expect to say that an IEM with two drivers is better than one with only one?
Can you show me just one case where, with the same frequency response and THD vs. level/frequency, an electrical to sound pressure wave transducer with two drivers is better than one with only one?
Since I've been interested in audio reproduction, I've always known that you use two (or more) drivers only when a single driver cannot cover the entire audio band with the required performance.
It's like saying that with equal total elaboration power and all othert parameters, a processor with more cores is better than one with a single core.
You use more cores when a single one cannot reach the required performance.
Otherwise, every time you run a program that cannot be parallelized at its best, the processor with a single core is always faster.
It's a matter of logic: you don't need to have the internal schematic of the processor...
My answer included all the previous posts not just yours. Please review the previous posts and you will understand the gist of my answer.
Why?
I think the Moondrop Chu II DSP are very interesting because they combine the ability to listen to hi-res audio tracks without losing the convenience of using the phone.
Honestly, I have not seen anything similar among the ASR tests that is better.
In this case, the performance, cost and ease of use are very interesting.
The problem is that using the Moondrop Chu II DSP with all the phones I have tried (about ten by now) you lose the ability to use the phone if you use USB Audio Player Pro and with the Samsung S22 the phone no longer works at all because it can only play music tracks (even uninstalling UAPP): you can no longer make or receive calls.
You asked me if I had the ThruthEar x Crinacle Zero:RED filter schematic to understand if an IEM with two drivers is better or worse than one with the same frequency response and THD and only one driver: what filter would you expect to say that an IEM with two drivers is better than one with only one?
Can you show me just one case where, with the same frequency response and THD vs. level/frequency, an electrical to sound pressure wave transducer with two drivers is better than one with only one?
Since I've been interested in audio reproduction, I've always known that you use two (or more) drivers only when a single driver cannot cover the entire audio band with the required performance.
It's like saying that with equal total elaboration power and all othert parameters, a processor with more cores is better than one with a single core.
You use more cores when a single one cannot reach the required performance.
Otherwise, every time you run a program that cannot be parallelized at its best, the processor with a single core is always faster.
It's a matter of logic: you don't need to have the internal schematic of the processor...
I don't think many on ASR care about hi-res audio. Just stating the facts. You can search about the topic if you want to know why or start a new thread.
You're saying you tried ten phones and they permanently lost call functionality when you installed an app for hi-res audio playback? Honestly, that doesn't make sense, at least not as an IEM issue. I'd recommend looking for a UAPP support channel. That will probably get you closer to the solution you want. Starting a debate about IEM design won't help much, and is off-topic in this thread.
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I think gcompari is talking about two separate issues
1. For Samsung phones, phone calls with Chu II DSP never works, I have a Samsung phone, i tried using another 3.5 mm headphone connect with the dongle dac works with phone calls, but Chu 2 dsp doesn't. When you make a phone call, what you hear always sounds distorted, it sounds like when you set the buffer size of your sound card very low for a low latency number, and it sounds distorted, It's like the entire sound has turned into just full of statics. I searched on net, and it seems like people with Samsung phones face the same issue when using Chu II.
example:
Using Moondrop CHU2 DSP for taking calls | The Indian Audiophile Forum
I received Moondrop CHU2 DSP today and it sounds amazing. But when I use it to take calls or make calls, I hear a crackling noise and it is completely unusable. I am using it with my Galaxy s24 phone. Do anyone have a similar issue?
www.theindianaudiophileforum.com
2. gcompari's second point is that some other phones have issued in playing high res audio. Since i don't have a need for playing high res, i don't really know about this one.
Note ever since gcompari brought up this topic in the thread, I reported again to the customer service, telling them to report to the technical staff, It just doesn't make sense if everybody with the Samsung phone faces the same issue, but the technical staff of the brand just doesn't know about this. They said that they have told the technical staff about this, but i never got a reply afterwards, I'm not sure.
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Disrupting call functionality might just be unevitable with some setups, given that UAPP takes direct control of the DAC by design. It would be prudent to select a verified DAC + phone combo beforehand if it's a hard requiremt. That's why I asked why he needs hires playback, because of the potential hurdles. The Nyquist theorem doesn't suggest it's worth the hassle, and he's already complaining about the issue he's having.
No as I said it's separate issues, why are we mixing that up again?
1. Raw Samsung phone without third party APP works with a different typeC dongle DAC but not Chu II DSP, I am facing this issue, without any APP installed.
2. Non-Samsung phone's problem with UAPP playback, but fine when making phone calls. I am not facing this issue but gcompari is.
Why are mixing this up? It's phone call distorted without any APP on Samsung phones, and UAPP playback distorted but no issue with phone calls on other phones. I am facing the first issue and so are other Samsung phone users, it has nothing to do with any APPs.
Mutiple issue can exist, sure.
I'm simply pointing out UAPP is picky and causes issues in numerous setups before anyone starts mixing up issues on that end.
Not all Chu 2 DSP users seem to experience the same range of issues with calls though?
I'm simply pointing out UAPP is picky and causes issues in numerous setups before anyone starts mixing up issues on that end.
Not all Chu 2 DSP users seem to experience the same range of issues with calls though?
@gcompari only mentioned issues (Chu-II not working) with phone calls:
1. You can’t properly take any phone call with Chu-II connected to a (any?) Samsung phone—either no sound or very distorted sound.
2. On non-Samsung phones, you can take phone calls (it works…), but if you play hires tracks with UAPP, you can no longer take phone calls (same as 1.). Disconnecting/reconnecting Chu-II fixes the problem (resets to default I assume).
I’m with @markanini on this one: this about disrupted phone functionality.
When you say “works” you refer to the phone functionality? Playing music tracks? Both? What does work with Chu-II DSP connected Samsung phone, and what does not work?
@gcompari did not say that UAPP playback was not working (Samsung or other), he said that, on non-Samsung phones, after playing hires tracks through UAPP, the phone functionality no longer works (until you disconnect/reconnect Chu-II DSP).
When you say you’re not facing this issue, have you tested this exact scenario on your phone?
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