In the search of Fiio FH9 IEMs alternative or the search for the best sounding IEMs in different budgets, up to $2200
I'm a big fan of Fiio’s sound quality, but I've been very disappointed by their physical build and technical reliability. While the audio on their devices is always superb, I've run into several issues with their products.
I love my Fiio FH9 IEMs—they feature a hybrid setup with one dynamic driver and six balanced armature drivers—and they were the best-sounding IEMs I could find within my $600 budget when I was shopping for IEMs a few years ago.
After my earlier experience with IEMs from Linsoul, I didn’t expect too much from these new ones. Even though, as I mentioned, the previously tested Linsoul 7Hz Timeless II offered great value for the price, they simply couldn’t compete with top-tier $600+ IEMs.
But I was wrong about the Linsoul TANGZU Zetian Wu Legend—they really surprised me. Don’t let the name Linsoul mislead you. As I wrote above, Linsoul is actually a distributor of Chinese hi-fi audio gear. They act as an excellent quality filter, finding the best Chinese hi-fi products that aren’t yet big enough to have their own global distribution (like Fiio or HIFIMAN). Linsoul helps bring these outstanding audio products to the world and currently lists more than 400 (!) IEMs on their product page. And that’s just the IEMs. Besides IEMs, they also sell headphones, DACs, amps, audio players, Bluetooth devices, audio cables, and other audio accessories.
The Zetian Wu Legend features a 14.2mm planar driver for deep, distortion-free bass and a 6mm flat diaphragm planar driver for smooth, detailed highs. This dual-driver setup is meticulously tuned to deliver a balanced sound across a wide frequency range, offering exceptional depth, clarity, and a dynamic, immersive listening experience.
The earbuds feel well-made, look beautiful, but the cable is on the thinner side.
They are comfortable to my ears.
Now to the testing.
At first, I noticed a similar issue to the one in the Linsoul 7Hz Timeless II—they can sound a little bit harsh. Although the TANGZU Zetian Wu Legend is less harsh, it's still not as neutral as the Fiio FH9. Fortunately, I got used to the slight harshness quickly, and I’d say it’s definitely less pronounced here than in the Timeless II. In fact, this slightly heightened harshness might be the only real negative of these IEMs!
They deliver good bass, clear and crisp sound, detailed instrument separation, and a decent soundstage. Of course, these aspects don’t quite reach the level of the Fiio FH9 ($600) or Campfire Audio Supermoon ($1000), but again, these IEMs cost just $220! I’ll probably add more details later, once I have more time with them, but right now I think the Linsoul TANGZU Zetian Wu Legend are the best-sounding $220 IEMs I’ve heard!
I liked them so much (again, considering their relatively low price) that I decided to order the second most expensive model from TANGZU—the TANGZU Tianpeng for $630. I'm very excited, they should arrive in 1-2 weeks (I suspect they will go from China, even though I ordered them on Amazon) and I'll keep you posted.
After my review, my friend got interested in them, so I tested them again—just to be sure. I compared them with the Campfire Audio Astrolith and the HIFIMAN HE1000 v2 (over-ear), both of which use pure planar drivers. Keep in mind, each competitor is ten times more expensive than the Tangzu Zetian Wu Legend.
The Campfire Audio Astrolith and HIFIMAN HE1000 v2 offered a wider soundstage and better instrument separation (especially noticeable when a lot of instruments are playing at once), but overall, the Tangzu Zetian Wu Legend held its ground! At one point, I even forgot I was listening to them and thought I had switched to the Campfire Audio Astrolith.
So, my strong recommendation stands—I still think these IEMs are the best I’ve heard in their price range.
My audiophile friend, who I mentioned in the previous update, ordered and just received the Tangzu Zetian Wu Legend a week ago —and he really likes them! Here's his review:
In the first two days, he thought they were good, but he didn’t realize just how good they were. He also found them not very comfortable at first, but after experimenting with different eartips included with the IEMs, he found a set that fits him much better. He didn’t notice any significant difference in sound between the various eartips, though.
Recently he tested some high-end closed-back headphones and realized that good closed-back models are well outside his budget, so he decided to try these IEMs as an alternative. He compared the TANGZU Zetian Wu Legend to the Beyerdynamic DT 990 Premium (the best over-ear headphones in the 300-dollar range, in my opinion) and to the HIFIMAN Ananda Nano Stealth Magnet V2 (the best over-ear headphones in the 1300-dollar range, in my opinion).
He preferred the midbass and midrange on the TANGZU over the Beyerdynamic DT 990 and also felt that the upper mids and treble were very high quality. He used to think that IEMs were not a serious option, but with the TANGZU Zetian Wu Legend he realized that IEMs can deliver very serious, high-quality sound. He says the overall sound of the TANGZU Zetian Wu Legend is very dense and rich, with a warm, pleasant tonality, and he found himself in love with Tangzu’s warmth.
When compared with the HIFIMAN Ananda Nano, he says the soundstage, detail, and clarity of the Ananda are better than those of the TANGZU Zetian Wu Legend. But again, keep in mind that the HIFIMAN Ananda Nano is probably among the best headphones in the 1000-dollar-plus bracket. He also says that the TANGZU Zetian Wu Legend has a very immersive presentation that makes you feel as if you are right in front of the stage.
Overall, the TANGZU Zetian Wu Legend exceeded his expectations and serves him as a great alternative to much more expensive closed-back headphones. As for the downsides, he mentions a somewhat mediocre soundstage depth (though here I respectfully disagree, when I tested them, the soundstage on the TANGZU Zetian Wu Legend seemed good, even if the difference versus IEMs and headphones costing ten times more was still noticeable).
Sennheiser MOMENTUM True Wireless 4 ($200 - $350)
Sennheiser MOMENTUM True Wireless 4 IEMs, each with a single 7mm dynamic driver, were the next pair I tried in my quest to find the best headphones within a $1000 budget.
This is a different contender because it’s wireless. It also features noise cancellation, allowing you to switch between ANC and aware modes.
The wireless design can be both an advantage and a disadvantage. Modern DACs can deliver excellent quality in a tiny package, but having the Bluetooth receiver and DAC inside each earbud means there’s less room for additional or larger drivers. And it shows—this model has the least impressive drivers of the bunch: just a single 7mm dynamic driver in each earbud. A single driver can be fine, if it's a planar driver. Planar drivers in my opinion are a revolution in headphones and IEMs. Unfortunately, Sennheiser MTW4 use a dynamic driver.
The second positive thing is that these IEMs are not fatiguing. I didn't notice any peaks at any frequencies (besides the bass, obviously).
Third, they fit comfortably.
Unfortunately (sorry, Anton), for me, that's where the positives end.
On to the negatives:
The downside of non-fatiguing sound is that it feels muffled, dull, too warm, and has softened highs.
Secondly, instrument separation isn't great—these can't compete with truly high-end, expensive IEMs or headphones.
Third, the soundstage feels too narrow, again compared to pricier and better-performing IEMs.
Fourth, the max volume is probably the lowest among all IEMs I've ever tried.
Campfire Audio SuperMoon (from the manufacturer based in Oregon, US) was the next pair I tested, and so far, they might be the best IEMs I've heard.
The only negatives (besides the price) is that they not as comfortable as some other IEMs for me (your experience may vary), and the cable does not look very durable. The discomfort is definitely noticeable. I really hope that if these win the sound quality battle, I’ll be able to find eartips that improve comfort. There are different eartips included, but I don’t want to try them all right now since I might end up returning these IEMs. I think, for example, memory foam tips can lose their “mint” condition if I use them.
I'll do more tests and add more details later.
I will copy part of the MoonDrop Meteor's description from the manufacturer's website:
My first impression is that they lack bass. I started testing them right after the Campfire Audio Supermoon, and the difference in bass—and in the “fullness,” “solidness,” and “density” of the sound—is striking. They also have less bass than the Fiio FH9.
The sound isn’t as clear or crisp, and the soundstage seems less wide than on either the Campfire Audio Supermoon or Fiio FH9. The frequency response isn’t perfectly neutral—it feels like there are peaks in some mid or high frequencies, which could lead to listening fatigue. At the same time, there are probably dips in other frequencies, because they sound less crisp, warmer, and duller compared to the Campfire Audio Supermoon.
Overall, on the Campfire Audio Supermoon, the sound is significantly clearer, airier, and has more “volume.”
My verdict on the MoonDrop Meteor is that, while they’re not bad, there are simply better options in 2025 for $550—and even for half that price. Personally, I think I prefer the sound of the TANGZU Zetian Wu Legend, which are twice cheaper.
Again, regarding “better options in 2025”… One thing I’ve noticed in my 10–15 years of pursuing better sound is how quickly audio gear keeps improving, especially from Chinese (and I'd say, US too) companies. I already mentioned above about Sennheiser losing the battle, but it's not just them, the similar situation is with other German and Japanese manufacturing mastodonts, like Audio-Technica, Denon, BeyerDynamic. I tend to buy new audio gear nearly every year, and it’s remarkable how much things improve every few years. For example, when I was choosing IEMs previously, there were far fewer good options in my $600 budget, and the sound quality for the price was much worse. TANGZU, for instance, was only founded in 2020. Last time I was in the market for IEMs, they weren’t really on anyone’s radar—and even now, many people still don’t know about them. But as I wrote above, their Zetian Wu model is perhaps the best IEM I’ve ever heard at $220, and some of their models are ranked very highly in various IEM ratings by trusted sources.
I think if this trend continues (and I'm sure it will), in a few years we'll be able to buy $200 IEMs or headphones with the sound quality that $2,000 IEMs or headphones had 10-15 years ago (2010 - 2015).
Ta-daaam!!! I had very, VERY high hopes for ThieAudio Monarch MKIII. They are often recommended on hi-fi forums and are ranked in the TOP 3 out of about 1000 (!) IEMs on the biggest IEM ranking site on the Internet (https://crinacle.com/rankings/iems/). To be fair, the model in the TOP 3 is the MKII and I got the MKIII. But I don’t think that should make a huge difference. I’ve read the MKIII has improved (more) bass.
These IEMs feature 2 dynamic drivers, 6 balanced armatures, and 2 electrostatic (!!!) drivers. Electrostatic drivers are usually found in high-end audio gear and provide stellar quality in the mid and high ranges (usually, additional drivers are used for bass).
The build quality seems good, the cable feels durable, and the fit is comfortable for my ears.
Right out of the box, it was clear they deliver excellent sound quality, and I knew I’d have to test them against my current leader—the Campfire Audio Supermoon.
The ThieAudio Monarch MKIII offers a mostly neutral frequency response and quality bass and mids; however, the highs felt a bit recessed. Maybe it’s just because I was comparing them to the Campfire Audio Supermoon, which is on the brighter side.
As I said, the overall sound quality is excellent, and these are not fatiguing. Instrument separation is great, and the soundstage is wide.
However, compared to the Campfire Audio Supermoon, the Supermoon has higher-quality bass in my opinion (again, the bass on the Supermoon is the best I’ve ever tested in any IEM) as well as a wider soundstage. The soundstage on the Supermoon is unbelievable—easily the best I’ve experienced among all IEMs I’ve had. Finally, the Campfire Audio Supermoon is brighter. While that can be fatiguing, in most cases the extra brightness makes the sound feel crisper and clearer.
Here’s a screenshot with the results of this battle:
So even though, to my ears, the Campfire Audio Supermoon won this tough battle, the ThieAudio Monarch MKIII still ranks in the top IEMs I’ve ever heard.
The more experience I got with planar drivers, the more I realized that I preferred their sound and found their sound quality to be superior to dynamic drivers and balanced armatures—at least to my ears and taste.
After listening to the Campfire Audio Supermoon (which has a single planar driver) and deciding it was the best IEM I had ever heard, I had high hopes for the Astrolith.
Planar drivers, despite the relatively large size, are capable of moving incredibly fast. This speed creates a great deal of sharp detail and overall resolution, presenting your tracks with life-like realism and creating a vast canvas on which every layer and element of your music is displayed.
Reflecting this driver's rapid, accurate movement is its outstanding impulse response - the ability of the driver to respond to signal and stop resulting movement quickly - allowing the driver to move from note to succeeding note without overlap or ‘smearing.’
Yet another advantage of planar technology is the incredibly low overall THD (Total Harmonic Distortion) ratio. Combined with the speed, precision, and even movement of the planar driver, this super low THD ratio adds another layer to the planar driver’s crisp, clean, and accurate sonic reproduction.
Ok, that's enough theory—let's get to the IEMs themselves.
The earphones themselves feel solid, but unfortunately, the cable is the same thin one used with the Campfire Audio Supermoon.
I’m glad the fit is better than the Supermoon; I was worried all their IEMs might be not very comfortable.
The sound is similar to the Supermoon: amazing, high-quality bass—fast, tight, and well-separated from other instruments, with extension down to very low frequencies. The bass may be a little amplified, but I like it. The soundstage is also extremely wide, the best I’ve heard in IEMs. The two planar drivers improve instrument separation and make the sound even clearer and crisper. The sound signature is very similar to the Supermoon, meaning the Astrolith also has bright highs, which some people may find fatiguing. However, I quickly got used to this, and now other IEMs sound too warm, too dull, too flat, or too "muddy" compared to the Astrolith (or the Supermoon, for that matter).
Overall, the Astrolith is just a better version of the Supermoon. How much better? Not twice better (even though the price is more than double), but I do hear an improvement, and I prefer the sound of the Astrolith in most songs. And since I can afford $2,200—as quality sound is one of the most important things in my life—I’m willing to pay for this upgrade over the Supermoon.
So, at this point, the Astrolith are the best-sounding IEMs I have ever listened to, and I will keep them :)
Campfire Audio Grand Luna features a hybrid design: a 14mm planar driver combined with two balanced armatures.
Grand Luna’s planar targets low and mid frequencies and applies its signature, vast dynamic range and rapid transient response. Grand Luna’s two premium balanced armatures orbit its central planar driver to accent and contribute their classic speed, detail, and resolution.
Out of the three Campfire Audio models I own (Supermoon, Grand Luna, and Astrolith), Grand Luna looks and feels the best: the stainless steel lid is much more attractive than the chromed lids on the Supermoon and Astrolith, and Grand Luna’s transparent shell reveals its internal components in a brilliant red finish.
SoftEars RSV MKII feature five balanced armature drivers.
Right away, I noticed the very thick cable. It looks like it’s easily the most durable of all the candidates I’ve tested this time—maybe even among all IEMs I’ve ever tried. I really liked this cable.
The earbuds themselves also feel well-made. The fit isn’t bad—definitely not the most comfortable, but also not as uncomfortable as the Supermoon, for example.
I compared them to the current leader, the Campfire Audio Astrolith.
If I’d tested the SoftEars RSV MKII in isolation, without A/B-ing with the best IEMs, I’d have said they’re excellent.
But compared to the Astrolith right away, a lot of differences stand out.
Now that my long process of testing and selection is finally complete, here are the final results:
Thank you for reading, and I hope this helps someone! :)
I love my Fiio FH9 IEMs—they feature a hybrid setup with one dynamic driver and six balanced armature drivers—and they were the best-sounding IEMs I could find within my $600 budget when I was shopping for IEMs a few years ago.
Unfortunately, both pairs died on me after about a year on average. To be exact, one pair failed after just six months (I plan to send it to Fiio under warranty, hoping they won't claim I broke it), and the second pair stopped working after about two years. Both had the same issue: the connection between the earbuds and cables is very poor, causing either intermittent failures or complete loss of function over time. I tried three different cables and also used Fiio’s UTSW5 Bluetooth earhooks, but the problem is definitely with the FH9s themselves.
Speaking of the Fiio UTSW5 Bluetooth earhooks—they have their own problems. About once or twice a month, one earhook disconnects and can’t be paired again. It takes about half an hour of trial and error to finally reconnect and get it working.
My Fiio X7 player, which is fantastic for sound quality and output power, started having issues with its amplified output: the volume now changes randomly.
So it's time for me to move on from Fiio, at least for IEMs. To be fair, the Fiio BTR15 and BTR17 Bluetooth DAC/AMPs have been working great so far.
Since I’m searching for an alternative to the Fiio FH9 and planning to test other highly-rated IEMs, I decided to share my short reviews here.
First, I checked multiple ratings on highly reputable hi-fi audio websites (https://crinacle.com/rankings/iems/, https://www.audiophile-heaven.com/, etc.) and also asked for advice on head-fi.org (probably the best forum for headphones).
I picked out a couple dozen models, with prices ranging from $200 to $2,200, then narrowed it down to those that I could easily return, since I’m very picky about sound and the chance of returning them is pretty high. So, I searched for the selected IEMs on Amazon (best return policy), Walmart (also a great return policy), Campfire Audio (excellent return policy), Audio46 (excellent selection, good return policy), and headphones.com (also excellent selection and good return policy).
I also tried to buy open-box units, but only from places that allow easy returns on open-box items—since some websites don’t accept returns on open-box at all. That way, the IEMs would have already been opened before me. When I received new items, I tried to open them with a surgeon’s precision, making sure to repack them exactly as they were—removing any fingerprints, dirt, or specks of dust.
Now, let’s begin.
Linsoul 7Hz Timeless II with large 14.5mm planar drivers became my first alternative.
Overall, the quality-to-price ratio is great here, and in my experience, these are definitely among the best IEMs for their price. If the manufacturer fixed the harshness, they’d be worth much more and could easily compete with $400+ IEMs.
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| Fiio FH9 ($600 when they were new) |
Speaking of the Fiio UTSW5 Bluetooth earhooks—they have their own problems. About once or twice a month, one earhook disconnects and can’t be paired again. It takes about half an hour of trial and error to finally reconnect and get it working.
My Fiio X7 player, which is fantastic for sound quality and output power, started having issues with its amplified output: the volume now changes randomly.
So it's time for me to move on from Fiio, at least for IEMs. To be fair, the Fiio BTR15 and BTR17 Bluetooth DAC/AMPs have been working great so far.
Since I’m searching for an alternative to the Fiio FH9 and planning to test other highly-rated IEMs, I decided to share my short reviews here.
I picked out a couple dozen models, with prices ranging from $200 to $2,200, then narrowed it down to those that I could easily return, since I’m very picky about sound and the chance of returning them is pretty high. So, I searched for the selected IEMs on Amazon (best return policy), Walmart (also a great return policy), Campfire Audio (excellent return policy), Audio46 (excellent selection, good return policy), and headphones.com (also excellent selection and good return policy).
I also tried to buy open-box units, but only from places that allow easy returns on open-box items—since some websites don’t accept returns on open-box at all. That way, the IEMs would have already been opened before me. When I received new items, I tried to open them with a surgeon’s precision, making sure to repack them exactly as they were—removing any fingerprints, dirt, or specks of dust.
Now, let’s begin.
Linsoul 7Hz Timeless II ($180 - $230)
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| Linsoul 7Hz Timeless II ($180 - $230) |
Linsoul 7Hz Timeless II with large 14.5mm planar drivers became my first alternative.
Linsoul does not manufacture IEMs themselves but operates primarily as a distributor and retailer of audio products from Chinese HiFi brands such as ThieAudio, Kiwi Ears, ZiiGaat, FiiO, KZ, and Tin HiFi. They buy complete IEMs from these manufacturers and resell them internationally, with a focus on Chinese Hi-Fi gear. Additionally, Linsoul offers customization services, such as custom-molded shells or faceplates for existing IEMs, which involves minor assembly or modification using parts from those manufacturers rather than full in-house production. Some brands they distribute, like ZiiGaat and ThieAudio, are considered "house brands" closely affiliated with Linsoul, but the actual manufacturing is handled by specialized factories in China.
I got them with some discount for $183 and have just finished testing them.
The construction and the cable seems solid. The cable is not as thick as on some other top IEMs, but it's decent.
Honestly, I think they sound better than their price suggests—they outperform some more expensive IEMs, and I definitely expected less. However, the sound is quite harsh, and I can already tell it will be very fatiguing at high volumes. This is my biggest issue with them. The soundstage isn’t as wide as on the Fiio FH9, although it's definitely very good for the price. Separation of instruments is also very good for the price. And the fit is comfortable to my ears.
Some people praise their sub bass, but I didn't notice anything super powerful. The bass is present, but not especially amplified to my ear.
Maybe some equalizer adjustments can make the sound a bit milder, in which case they'd be an excellent option for the price.
I've experienced headphones that cost thousands of dollars, so my standards are extremely high. That's why I can't say I'm completely happy with this Linsoul 7Hz Timeless II model. Still, I can see them making a lot of people happy—especially those who aren’t as obsessive about sound quality as I am.
Maybe some equalizer adjustments can make the sound a bit milder, in which case they'd be an excellent option for the price.
I've experienced headphones that cost thousands of dollars, so my standards are extremely high. That's why I can't say I'm completely happy with this Linsoul 7Hz Timeless II model. Still, I can see them making a lot of people happy—especially those who aren’t as obsessive about sound quality as I am.
(Linsoul) TANGZU Zetian Wu Legend ($220)
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| Linsoul TANGZU Zetian Wu Legend ($220) |
After my earlier experience with IEMs from Linsoul, I didn’t expect too much from these new ones. Even though, as I mentioned, the previously tested Linsoul 7Hz Timeless II offered great value for the price, they simply couldn’t compete with top-tier $600+ IEMs.
But I was wrong about the Linsoul TANGZU Zetian Wu Legend—they really surprised me. Don’t let the name Linsoul mislead you. As I wrote above, Linsoul is actually a distributor of Chinese hi-fi audio gear. They act as an excellent quality filter, finding the best Chinese hi-fi products that aren’t yet big enough to have their own global distribution (like Fiio or HIFIMAN). Linsoul helps bring these outstanding audio products to the world and currently lists more than 400 (!) IEMs on their product page. And that’s just the IEMs. Besides IEMs, they also sell headphones, DACs, amps, audio players, Bluetooth devices, audio cables, and other audio accessories.
The Zetian Wu Legend features a 14.2mm planar driver for deep, distortion-free bass and a 6mm flat diaphragm planar driver for smooth, detailed highs. This dual-driver setup is meticulously tuned to deliver a balanced sound across a wide frequency range, offering exceptional depth, clarity, and a dynamic, immersive listening experience.
The earbuds feel well-made, look beautiful, but the cable is on the thinner side.
They are comfortable to my ears.
Now to the testing.
At first, I noticed a similar issue to the one in the Linsoul 7Hz Timeless II—they can sound a little bit harsh. Although the TANGZU Zetian Wu Legend is less harsh, it's still not as neutral as the Fiio FH9. Fortunately, I got used to the slight harshness quickly, and I’d say it’s definitely less pronounced here than in the Timeless II. In fact, this slightly heightened harshness might be the only real negative of these IEMs!
They deliver good bass, clear and crisp sound, detailed instrument separation, and a decent soundstage. Of course, these aspects don’t quite reach the level of the Fiio FH9 ($600) or Campfire Audio Supermoon ($1000), but again, these IEMs cost just $220! I’ll probably add more details later, once I have more time with them, but right now I think the Linsoul TANGZU Zetian Wu Legend are the best-sounding $220 IEMs I’ve heard!
Update:
The Campfire Audio Astrolith and HIFIMAN HE1000 v2 offered a wider soundstage and better instrument separation (especially noticeable when a lot of instruments are playing at once), but overall, the Tangzu Zetian Wu Legend held its ground! At one point, I even forgot I was listening to them and thought I had switched to the Campfire Audio Astrolith.
So, my strong recommendation stands—I still think these IEMs are the best I’ve heard in their price range.
2nd Update:
In the first two days, he thought they were good, but he didn’t realize just how good they were. He also found them not very comfortable at first, but after experimenting with different eartips included with the IEMs, he found a set that fits him much better. He didn’t notice any significant difference in sound between the various eartips, though.
Recently he tested some high-end closed-back headphones and realized that good closed-back models are well outside his budget, so he decided to try these IEMs as an alternative. He compared the TANGZU Zetian Wu Legend to the Beyerdynamic DT 990 Premium (the best over-ear headphones in the 300-dollar range, in my opinion) and to the HIFIMAN Ananda Nano Stealth Magnet V2 (the best over-ear headphones in the 1300-dollar range, in my opinion).
He preferred the midbass and midrange on the TANGZU over the Beyerdynamic DT 990 and also felt that the upper mids and treble were very high quality. He used to think that IEMs were not a serious option, but with the TANGZU Zetian Wu Legend he realized that IEMs can deliver very serious, high-quality sound. He says the overall sound of the TANGZU Zetian Wu Legend is very dense and rich, with a warm, pleasant tonality, and he found himself in love with Tangzu’s warmth.
When compared with the HIFIMAN Ananda Nano, he says the soundstage, detail, and clarity of the Ananda are better than those of the TANGZU Zetian Wu Legend. But again, keep in mind that the HIFIMAN Ananda Nano is probably among the best headphones in the 1000-dollar-plus bracket. He also says that the TANGZU Zetian Wu Legend has a very immersive presentation that makes you feel as if you are right in front of the stage.
Overall, the TANGZU Zetian Wu Legend exceeded his expectations and serves him as a great alternative to much more expensive closed-back headphones. As for the downsides, he mentions a somewhat mediocre soundstage depth (though here I respectfully disagree, when I tested them, the soundstage on the TANGZU Zetian Wu Legend seemed good, even if the difference versus IEMs and headphones costing ten times more was still noticeable).
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| Sennheiser MOMENTUM True Wireless 4 ($200 - $350) |
This is a different contender because it’s wireless. It also features noise cancellation, allowing you to switch between ANC and aware modes.
The wireless design can be both an advantage and a disadvantage. Modern DACs can deliver excellent quality in a tiny package, but having the Bluetooth receiver and DAC inside each earbud means there’s less room for additional or larger drivers. And it shows—this model has the least impressive drivers of the bunch: just a single 7mm dynamic driver in each earbud. A single driver can be fine, if it's a planar driver. Planar drivers in my opinion are a revolution in headphones and IEMs. Unfortunately, Sennheiser MTW4 use a dynamic driver.
To be honest, in my experience, really good sound in IEMs starts at $300, so I didn't have much hope for this Sennheiser model which I got for $200, but which often costs closer to $300. But my friend Anton highly recommended them. Plus, they have powerful bass, and after buying 2 x 18" subwoofers I've temporarily become a basshead :) I'm sure this bass addiction will pass, but for now I'm enjoying lots of ultra low bass.
So, the first thing I did with the Sennheiser MTW4s was to test the bass response. It's truly powerful and amplified. I checked the frequency response graphs, and at 20 Hz it's about 4 dB higher than on my favorite Fiio FH9. So for bass, these are good.The second positive thing is that these IEMs are not fatiguing. I didn't notice any peaks at any frequencies (besides the bass, obviously).
Third, they fit comfortably.
Unfortunately (sorry, Anton), for me, that's where the positives end.
On to the negatives:
The downside of non-fatiguing sound is that it feels muffled, dull, too warm, and has softened highs.
Secondly, instrument separation isn't great—these can't compete with truly high-end, expensive IEMs or headphones.
Third, the soundstage feels too narrow, again compared to pricier and better-performing IEMs.
Fourth, the max volume is probably the lowest among all IEMs I've ever tried.
And finally, while the bass is powerful, in my opinion, its quality isn’t great. It’s not very tight, and it doesn’t remain clearly separated when multiple instruments are playing. This difference became especially obvious when I compared the bass to my next contender—the Campfire Audio SuperMoon.
I don't want to bring even more negatives about Sennheiser... I love this company, and they produce some of the best headphones and IEMs in the world. For example, their HD800 open headphones got the 2nd place in my selection of headphones in $2000 price range (HIFIMAN HE1000 v2 won for me and I kept them).
However, I feel like Sennheiser got too comfortable with being a leader in the world of hi-fi headphones and they start losing the battle to relatively new brands, like Chinese Fiio or HIFIMAN, or some US brands, like Dan Clark. These competing manufacturers constantly increase the sound quality by using multiple drivers, or using planar drivers, or using new revolutionary technologies.
Dan Clark, for example, uses exclusively magnetic planar drivers, and are renowned for delivering a sense of openness and spaciousness (in their closed headphones) typically associated with top-tier open-back models like the Sennheiser HD 800 S or advanced HIFIMAN models. This "open-like" quality stems from a combination of innovative engineering, precise tuning, and materials science that minimizes the usual sonic drawbacks of closed designs—such as boxy resonance, compressed staging, and veiled highs—while retaining isolation benefits.
Sennheiser, for some reason, is not really growing or improving. For example, one of their top IEMs: IE 600 (costing $700 - $800), also uses just a single 7mm dynamic driver.
I'm afraid if it continues like this Sennheiser may go out of business if they don't start improving rapidly.
Campfire Audio SuperMoon ($900 - $1100)
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| Campfire Audio SuperMoon ($900 - $1100) |
The Campfire Audio Supermoon in-ear monitors feature a single full-range 14mm planar magnetic driver, marking the company's first implementation of this technology in an IEM. This custom-developed driver combines a large diaphragm for powerful, textured bass with the speed and precision of planar magnetics for crisp mids, detailed resolution, and sparkling highs across a wide frequency spectrum.
There’s currently a sale on their official website, so you can get them for $900, but I paid $1100 on Amazon—overpaying, just to have the option to return them if I end up not liking them.
The bass is powerful, high-quality, tight, and clearly separated. The bass may be a little amplified, but not that it sounds too much. There are some peaks in high frequencies, which may make these IEMs sound a little harsh in some tracks. The sound is very crisp and clear, with excellent instrument separation. The soundstage is VERY wide. In fact it's the widest soundstage I've ever heard in IEMs. The sound is "airy". I think overall they sound better to my ear than my favorite Fiio FH9.
The only negatives (besides the price) is that they not as comfortable as some other IEMs for me (your experience may vary), and the cable does not look very durable. The discomfort is definitely noticeable. I really hope that if these win the sound quality battle, I’ll be able to find eartips that improve comfort. There are different eartips included, but I don’t want to try them all right now since I might end up returning these IEMs. I think, for example, memory foam tips can lose their “mint” condition if I use them.
I'll do more tests and add more details later.
MoonDrop Meteor ($550)
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| MoonDrop Meteor ($550) |
I will copy part of the MoonDrop Meteor's description from the manufacturer's website:
One Dynamic Driver + Two Balanced Armatures + 4 Planar Drivers Tribrid IEM, XTM complex technology frequency-crossover architecture.The IEMs and the cable seem pretty durable and well-built.
The uniquely designed multi-driver frequency crossover acoustic structure allows the innovative placement of the 13mm oversized bass dynamic driver.
Four miniature treble planar driver, Lower distortion, wider range and higher resolution.
The customized mids composite dual balanced armatures are designed to deliver exceptional sound quality and a dynamic fullness that perfectly fits the Target.
My first impression is that they lack bass. I started testing them right after the Campfire Audio Supermoon, and the difference in bass—and in the “fullness,” “solidness,” and “density” of the sound—is striking. They also have less bass than the Fiio FH9.
The sound isn’t as clear or crisp, and the soundstage seems less wide than on either the Campfire Audio Supermoon or Fiio FH9. The frequency response isn’t perfectly neutral—it feels like there are peaks in some mid or high frequencies, which could lead to listening fatigue. At the same time, there are probably dips in other frequencies, because they sound less crisp, warmer, and duller compared to the Campfire Audio Supermoon.
Overall, on the Campfire Audio Supermoon, the sound is significantly clearer, airier, and has more “volume.”
My verdict on the MoonDrop Meteor is that, while they’re not bad, there are simply better options in 2025 for $550—and even for half that price. Personally, I think I prefer the sound of the TANGZU Zetian Wu Legend, which are twice cheaper.
Again, regarding “better options in 2025”… One thing I’ve noticed in my 10–15 years of pursuing better sound is how quickly audio gear keeps improving, especially from Chinese (and I'd say, US too) companies. I already mentioned above about Sennheiser losing the battle, but it's not just them, the similar situation is with other German and Japanese manufacturing mastodonts, like Audio-Technica, Denon, BeyerDynamic. I tend to buy new audio gear nearly every year, and it’s remarkable how much things improve every few years. For example, when I was choosing IEMs previously, there were far fewer good options in my $600 budget, and the sound quality for the price was much worse. TANGZU, for instance, was only founded in 2020. Last time I was in the market for IEMs, they weren’t really on anyone’s radar—and even now, many people still don’t know about them. But as I wrote above, their Zetian Wu model is perhaps the best IEM I’ve ever heard at $220, and some of their models are ranked very highly in various IEM ratings by trusted sources.
ThieAudio Monarch MKIII ($1000)
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| ThieAudio Monarch MKIII ($1000) |
Ta-daaam!!! I had very, VERY high hopes for ThieAudio Monarch MKIII. They are often recommended on hi-fi forums and are ranked in the TOP 3 out of about 1000 (!) IEMs on the biggest IEM ranking site on the Internet (https://crinacle.com/rankings/iems/). To be fair, the model in the TOP 3 is the MKII and I got the MKIII. But I don’t think that should make a huge difference. I’ve read the MKIII has improved (more) bass.
These IEMs feature 2 dynamic drivers, 6 balanced armatures, and 2 electrostatic (!!!) drivers. Electrostatic drivers are usually found in high-end audio gear and provide stellar quality in the mid and high ranges (usually, additional drivers are used for bass).
The build quality seems good, the cable feels durable, and the fit is comfortable for my ears.
Right out of the box, it was clear they deliver excellent sound quality, and I knew I’d have to test them against my current leader—the Campfire Audio Supermoon.
The ThieAudio Monarch MKIII offers a mostly neutral frequency response and quality bass and mids; however, the highs felt a bit recessed. Maybe it’s just because I was comparing them to the Campfire Audio Supermoon, which is on the brighter side.
As I said, the overall sound quality is excellent, and these are not fatiguing. Instrument separation is great, and the soundstage is wide.
However, compared to the Campfire Audio Supermoon, the Supermoon has higher-quality bass in my opinion (again, the bass on the Supermoon is the best I’ve ever tested in any IEM) as well as a wider soundstage. The soundstage on the Supermoon is unbelievable—easily the best I’ve experienced among all IEMs I’ve had. Finally, the Campfire Audio Supermoon is brighter. While that can be fatiguing, in most cases the extra brightness makes the sound feel crisper and clearer.
Here’s a screenshot with the results of this battle:
So even though, to my ears, the Campfire Audio Supermoon won this tough battle, the ThieAudio Monarch MKIII still ranks in the top IEMs I’ve ever heard.
Campfire Audio Astrolith ($2200)
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| Campfire Audio Astrolith ($2200) |
The more experience I got with planar drivers, the more I realized that I preferred their sound and found their sound quality to be superior to dynamic drivers and balanced armatures—at least to my ears and taste.
After listening to the Campfire Audio Supermoon (which has a single planar driver) and deciding it was the best IEM I had ever heard, I had high hopes for the Astrolith.
The Astrolith feature dual planar magnetic driver configuration: a 14mm planar magnetic main driver that ranges from sub-bass to mid frequencies and blends seamlessly with a 6mm planar high-frequency tweeter.
Reflecting this driver's rapid, accurate movement is its outstanding impulse response - the ability of the driver to respond to signal and stop resulting movement quickly - allowing the driver to move from note to succeeding note without overlap or ‘smearing.’
Ok, that's enough theory—let's get to the IEMs themselves.
The earphones themselves feel solid, but unfortunately, the cable is the same thin one used with the Campfire Audio Supermoon.
I’m glad the fit is better than the Supermoon; I was worried all their IEMs might be not very comfortable.
The sound is similar to the Supermoon: amazing, high-quality bass—fast, tight, and well-separated from other instruments, with extension down to very low frequencies. The bass may be a little amplified, but I like it. The soundstage is also extremely wide, the best I’ve heard in IEMs. The two planar drivers improve instrument separation and make the sound even clearer and crisper. The sound signature is very similar to the Supermoon, meaning the Astrolith also has bright highs, which some people may find fatiguing. However, I quickly got used to this, and now other IEMs sound too warm, too dull, too flat, or too "muddy" compared to the Astrolith (or the Supermoon, for that matter).
Overall, the Astrolith is just a better version of the Supermoon. How much better? Not twice better (even though the price is more than double), but I do hear an improvement, and I prefer the sound of the Astrolith in most songs. And since I can afford $2,200—as quality sound is one of the most important things in my life—I’m willing to pay for this upgrade over the Supermoon.
So, at this point, the Astrolith are the best-sounding IEMs I have ever listened to, and I will keep them :)
Campfire Audio Grand Luna
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| Campfire Audio Grand Luna ($1400) |
Campfire Audio Grand Luna features a hybrid design: a 14mm planar driver combined with two balanced armatures.
Grand Luna’s planar targets low and mid frequencies and applies its signature, vast dynamic range and rapid transient response. Grand Luna’s two premium balanced armatures orbit its central planar driver to accent and contribute their classic speed, detail, and resolution.
Out of the three Campfire Audio models I own (Supermoon, Grand Luna, and Astrolith), Grand Luna looks and feels the best: the stainless steel lid is much more attractive than the chromed lids on the Supermoon and Astrolith, and Grand Luna’s transparent shell reveals its internal components in a brilliant red finish.
The cable is also thicker and feels more durable compared to those on the Supermoon and Astrolith.
The fit is comfortable for my ears.
The idea behind using two balanced armatures for high frequencies is to minimize the fatiguing highs that pure planar drivers can have—and it works. Grand Luna definitely has milder, less fatiguing highs.
But while Grand Luna delivers excellent overall sound quality, I did encounter a couple of issues. First, for some reason, the bass is less clear and tight compared to the Supermoon and Astrolith; it feels smeared. Second, I realized that I prefer the sound of pure planar drivers—even with their harsher high frequencies—over the softer high frequencies of hybrids. After experiencing the Supermoon and Astrolith, Grand Luna sounded less clear and crisp to me; they felt a little too warm, flat, and dull in comparison.
So, while the Grand Luna is an excellent IEM and may be one of the best options for people who don’t like a bit of harshness from pure planar drivers, for me - it lost the battle to the Supermoon and Astrolith.
The idea behind using two balanced armatures for high frequencies is to minimize the fatiguing highs that pure planar drivers can have—and it works. Grand Luna definitely has milder, less fatiguing highs.
But while Grand Luna delivers excellent overall sound quality, I did encounter a couple of issues. First, for some reason, the bass is less clear and tight compared to the Supermoon and Astrolith; it feels smeared. Second, I realized that I prefer the sound of pure planar drivers—even with their harsher high frequencies—over the softer high frequencies of hybrids. After experiencing the Supermoon and Astrolith, Grand Luna sounded less clear and crisp to me; they felt a little too warm, flat, and dull in comparison.
So, while the Grand Luna is an excellent IEM and may be one of the best options for people who don’t like a bit of harshness from pure planar drivers, for me - it lost the battle to the Supermoon and Astrolith.
SoftEars RSV-MKII ($700)
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| SoftEars RSV-MKII ($700) |
SoftEars RSV MKII feature five balanced armature drivers.
Right away, I noticed the very thick cable. It looks like it’s easily the most durable of all the candidates I’ve tested this time—maybe even among all IEMs I’ve ever tried. I really liked this cable.
The earbuds themselves also feel well-made. The fit isn’t bad—definitely not the most comfortable, but also not as uncomfortable as the Supermoon, for example.
I compared them to the current leader, the Campfire Audio Astrolith.
If I’d tested the SoftEars RSV MKII in isolation, without A/B-ing with the best IEMs, I’d have said they’re excellent.
But compared to the Astrolith right away, a lot of differences stand out.
The bass on the RSV MKII is good, but it’s not as fast or tight as on the Astrolith.
High frequencies feel suppressed, and they aren’t as well-separated from other instruments as on the Astrolith. For example, in some song, with the Astrolith I noticed that when the drummer hits a cymbal, the initial hit is clearly heard and you can hear the cymbal’s tail fade for a few seconds. With the SoftEars, the cymbal hit isn’t as pronounced, and the decay fades away too quickly and isn’t as clear.
Because of this, I can’t really say the instrument separation is great on the SoftEars.
The soundstage is also not as wide as on the Astrolith and feels less spacious.
Overall, the SoftEars RSV MKII come across as a bit flatter and duller compared to the Astrolith.
My biggest issue with SoftEars is the suppressed highs. The highs often seem lowered on BA/DD IEMs compared to planar drivers, but here that suppression is more pronounced. Maybe that’s why they’re called “Soft Ears.”
I suppose the SoftEars RSV MKII can compete with other IEMs around the $700 mark, but—at least to my ears and taste—they clearly lose out to the more expensive models from Campfire Audio.
High frequencies feel suppressed, and they aren’t as well-separated from other instruments as on the Astrolith. For example, in some song, with the Astrolith I noticed that when the drummer hits a cymbal, the initial hit is clearly heard and you can hear the cymbal’s tail fade for a few seconds. With the SoftEars, the cymbal hit isn’t as pronounced, and the decay fades away too quickly and isn’t as clear.
Because of this, I can’t really say the instrument separation is great on the SoftEars.
The soundstage is also not as wide as on the Astrolith and feels less spacious.
Overall, the SoftEars RSV MKII come across as a bit flatter and duller compared to the Astrolith.
My biggest issue with SoftEars is the suppressed highs. The highs often seem lowered on BA/DD IEMs compared to planar drivers, but here that suppression is more pronounced. Maybe that’s why they’re called “Soft Ears.”
I suppose the SoftEars RSV MKII can compete with other IEMs around the $700 mark, but—at least to my ears and taste—they clearly lose out to the more expensive models from Campfire Audio.
Tangzu Tianpeng ($630)
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| Tangzu Tianpeng ($630) |
After testing the Tangzu Zetian Wu Legend and deciding they are the best IEMs in their price range—and possibly even in categories twice as expensive—I had very high hopes for the Tangzu Tianpeng, Tangzu’s second most expensive IEM.
At the same time, I’ve realized I really prefer planar sound; in recent years, every headphone and IEM I’ve chosen as my favorite (to my ear and taste) has been planar. I started to lose faith in non-planar drivers and thought maybe it’s time for me to write off non-planar headphones and IEMs altogether. Because of this, even though I had high expectations for the Tangzu Tianpeng, I doubted they could actually compete with my current leaders—Campfire Audio’s Supermoon and Astrolith, both featuring planar drivers.
However, Tangzu Tianpeng surprised me—a lot!
Tangzu Tianpeng feature a large 14.2mm dynamic driver for bass, six balanced armatures for mids and highs, plus a bone conduction unit for precise bass transmission and improved clarity.
The build quality seems excellent. The shells are smooth, pleasant to the touch, and comfortable in my ears. The stock cable is thick and a bit shorter than typical (not a problem for me, but something to note). It’s braided rope; personally, I prefer cables wrapped in TPU (thermoplastic polyurethane) since they’re easier to clean, but this isn’t a dealbreaker for me.
Tangzu Tianpeng only comes with a 4.4mm balanced plug, and at this price, I think they should have included a 3.5mm adapter. I’ll have to order one separately—since not all my devices have a 4.4mm output.
Now to the main advantage of Tangzu Tianpeng - their sound!
Right from the first listen, even before direct comparisons with Campfire Audio, I could tell the Tianpeng’s sound quality was excellent. But I didn’t immediately realize just how good it actually was.
Once I compared them directly to Campfire Astrolith, I realized: Tangzu Tianpeng is a genuine and formidable competitor to Campfire Audio’s Astrolith and Supermoon. No other IEM I’ve tested or heard has managed to compete this closely with Astrolith!
Bass is top-notch: powerful (but not overwhelming) and very well separated from other instruments. In most cases, I probably prefer Astrolith’s bass, since Astrolith and Supermoon deliver the best bass I’ve ever heard from IEMs. But the Tianpeng comes impressively close—and likely beats the bass in all other non-Campfire IEMs I’ve tried.
Mid frequencies are well pronounced; vocal playback is often amazing. In fact, I’d probably choose Tianpeng for singer’s voices above any other IEM. That being said, there is a slight peak around 500–1000 Hz. For vocals, this means extra clarity; for strong drum hits, this peak can be a bit much, but it isn’t a major issue—the peak isn’t high enough to be bothersome.
High frequencies are very well executed, better than most non-planar IEMs I’ve heard. Still, they aren’t as clear and distinct as planars in the highs—planars are just hard to beat here.
The overall frequency response is close to reference, with that small peak somewhere at 500-1000 Hz. Yet they’re more neutral than most IEMs I’ve tried, which I consider a plus.
The tonality is very pleasant—slightly on the warmer side, which I like.
The sound feels rich, which I also like.
Instrument separation is superb—truly among the best I’ve heard in IEMs.
Soundstage is excellent, though it loses to the Campfire Audio planars. This is because, in my experience, the clear, pronounced highs of planars help widen the soundstage.
When compared head-to-head with Campfire Audio Astrolith, the Astrolith won 10:7, which is still a spectacular performance for Tangzu Tianpeng—no other manufacturer has ever come this close to toppling Campfire Audio Astrolith (or Supermoon).
In the end, I genuinely loved the Tangzu Tianpeng. I highly recommend them and will be keeping them alongside my Campfire Audio Astrolith.
At the same time, I’ve realized I really prefer planar sound; in recent years, every headphone and IEM I’ve chosen as my favorite (to my ear and taste) has been planar. I started to lose faith in non-planar drivers and thought maybe it’s time for me to write off non-planar headphones and IEMs altogether. Because of this, even though I had high expectations for the Tangzu Tianpeng, I doubted they could actually compete with my current leaders—Campfire Audio’s Supermoon and Astrolith, both featuring planar drivers.
However, Tangzu Tianpeng surprised me—a lot!
Tangzu Tianpeng feature a large 14.2mm dynamic driver for bass, six balanced armatures for mids and highs, plus a bone conduction unit for precise bass transmission and improved clarity.
The build quality seems excellent. The shells are smooth, pleasant to the touch, and comfortable in my ears. The stock cable is thick and a bit shorter than typical (not a problem for me, but something to note). It’s braided rope; personally, I prefer cables wrapped in TPU (thermoplastic polyurethane) since they’re easier to clean, but this isn’t a dealbreaker for me.
Tangzu Tianpeng only comes with a 4.4mm balanced plug, and at this price, I think they should have included a 3.5mm adapter. I’ll have to order one separately—since not all my devices have a 4.4mm output.
Now to the main advantage of Tangzu Tianpeng - their sound!
Right from the first listen, even before direct comparisons with Campfire Audio, I could tell the Tianpeng’s sound quality was excellent. But I didn’t immediately realize just how good it actually was.
Once I compared them directly to Campfire Astrolith, I realized: Tangzu Tianpeng is a genuine and formidable competitor to Campfire Audio’s Astrolith and Supermoon. No other IEM I’ve tested or heard has managed to compete this closely with Astrolith!
Bass is top-notch: powerful (but not overwhelming) and very well separated from other instruments. In most cases, I probably prefer Astrolith’s bass, since Astrolith and Supermoon deliver the best bass I’ve ever heard from IEMs. But the Tianpeng comes impressively close—and likely beats the bass in all other non-Campfire IEMs I’ve tried.
Mid frequencies are well pronounced; vocal playback is often amazing. In fact, I’d probably choose Tianpeng for singer’s voices above any other IEM. That being said, there is a slight peak around 500–1000 Hz. For vocals, this means extra clarity; for strong drum hits, this peak can be a bit much, but it isn’t a major issue—the peak isn’t high enough to be bothersome.
High frequencies are very well executed, better than most non-planar IEMs I’ve heard. Still, they aren’t as clear and distinct as planars in the highs—planars are just hard to beat here.
The overall frequency response is close to reference, with that small peak somewhere at 500-1000 Hz. Yet they’re more neutral than most IEMs I’ve tried, which I consider a plus.
The tonality is very pleasant—slightly on the warmer side, which I like.
The sound feels rich, which I also like.
Instrument separation is superb—truly among the best I’ve heard in IEMs.
Soundstage is excellent, though it loses to the Campfire Audio planars. This is because, in my experience, the clear, pronounced highs of planars help widen the soundstage.
When compared head-to-head with Campfire Audio Astrolith, the Astrolith won 10:7, which is still a spectacular performance for Tangzu Tianpeng—no other manufacturer has ever come this close to toppling Campfire Audio Astrolith (or Supermoon).
In the end, I genuinely loved the Tangzu Tianpeng. I highly recommend them and will be keeping them alongside my Campfire Audio Astrolith.
Conclusion and winners
Campfire Audio Astrolith ($2200) - Best IEMs in $2200 budget
Campfire Audio Supermoon ($1000) - Best IEMs in $1000 budget
Tangzu Tianpeng ($630) - Best IEMs in $800 budget (and were it not for the Supermoon, they'd also be the best IEMs in the ~$1500 budget)
Tangzu Zetian Wu Legend ($220) - Best IEMs in $400 budget
Best price-to-sound-quality ratio: Tangzu Tianpeng & Tangzu Zetian Wu Legend
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