-10mm Ultra LCP Clear Analysis and 6mm Titanium Diaphragms -Super big stage with bass textures to die for -Elevated bass in the series -Clean tight and well organized LCP 10mm sub-bass tone -Does vocals with charm -Well rounded, playing any and every genre like it was made for it! -Warm subtle W swagger with a little less bass physicality than ALL the SPA 11.4mm full-range DDs -Included cable looks more like an aftermarket purchase than any included cable this year -Fun and creative packaging -Weighs 6 grams along with universal custom data-base form-factor design -The money from just a phone, but scales upward with better sources -The competent STA sub-bass experience
Cons:
Welcome to the 2025 IEM market, there are no downsides here? Maybe below average outside noise occlusion?
EarAcoustic STA-Pro MAX Recarmoose June 7th, 2025
EarAcoustic STA-Pro MAX 2 Dynamic Driver 2Pin 0.78mm HiFi Audiophile In-ear Earphone IEMs STA-Pro MAX
Unit: 10MM Ultra Clear Analysis Dual Magnetic LCP Diaphragm+6MM Titanium Plated Diaphragm Dynamic Coil Unit Sensitivity: 110dB Impedance: 30 ohm Frequency response range: 10-30kHz Wire specification: 0.78MM dual pin oxygen free copper and silver-plated wire mixed weave 1.2M
Hey what’s up Head-Fi’ers?
Another day, another review! Though this one is special. Now many reviews are special only here we have one of the more pricey EarAcoustic’s from The Fragrant Zither. So far I have heard 7 of the Silver Angel series. Here they are with a short rundown………
Top left to right: EarAcoustic STA-Pro Universal IEM $39.90 Shows brighter than the $49.90 STA-HI End. This idea is maybe that as you go up the scale you are met with a refinement of sorts?
EarAcoustic STA-Pro Ultra Universal IEM $49.90 Middle of the road brightness and more bass found due to the lowered treble and upper midrange.
EarAcoustic STA-Pro Max Universal IEM (This one) $79.90 Thicker, more note-weight and density, so less noticed upper midrange and treble, probably appearing less contrasty in a more expensive way? Plus it has an interesting smokey faceplate that no other IEMs in the STA series have! A huge authoritative stage holding bass textures to die for, different than the other STA series I’ve experienced! Glorious STA sub-bass due to 10mm LCP DD!
2nd row left to right: EarAcoustic STA-Hi End Universal IEM $49.90 The brightest second only to the STA-Pro, a smoother bigger stage, and due to a reduction in bass authority, probably this 10mm DD taken to the limits almost of lesser presence, which catapults the midrange and treble out!
EarAcoustic SPA Hi-End Ultra Universal IEM $189.90 The cats meow here in my limited experience, remember I have 5 more to hear to complete the series. But this is a great starter place to hear the SPA-Pro series, now they also make a basic $99.90 resin SPA-Pro, which is coming to my house next. Good for cold climate use, so you get the 11.4mm DD and the resin shell!
TOTL SPA Limited Edition Universal IEM $429.90 The bomb, no more needs to be said, read my review of it if you want more info.
EarAcoustic SPA-Pro Ultra Universal IEM $149.90 A great way to get into the SPA sound, with less diamond earring effects, though maybe you want to pimp-out? Choose the ($40.00 more) SPA Hi-End Ultra instead, and have smoother sound, plus flash.
The Fragrant Zither:
This is all a little confusing right? I mean why would a company like TFZ release a whole slew of IEMs slightly different? That’s what I thought about the subject. Then after hearing 7 of them I started to see how each one was a little different and the driver chemistry was altered to procure a slightly different sound character, as well as stage ideas and tonal realizations unique to each one. Now to make this simple there are two basic series.
The Star series and the Spark series:
The Spa is the upper line composed of a different shell of a different shape and a single 11.4mm DD of various make-ups. The Star series is a 10mm and a 6mm DD. Now the Star series are all chrome plated resin and the Spark series are primarily metal, all except the EarAcoustic Audio SPA-Pro which is chrome plated resin. The 8th of the series, the SPA-Pro should be at my door in a day or so. To be fully complete there are actually 13 in the whole series. This is due to the Limited Edition having two surfacing styles, as well as 5 of the Spark series, and 8 of the Star series.
STAR Series: STA-Pro: STA-Pro Ultra: STA-Pro MAX: STA-Hi End: STA-Hi End MAX:
SPARK Series: SPA-Pro: SPA-Pro Ultra: SPA-Pro MAX: SPA-Hi End : SPA-Hi End Ultra: SPA-Hi End MAX: SPA-Limited Edition X 2 (Different shell surfacing)
SPA & STA Style Explanation:
1. SPA series compared to STA series overall style has a slightly richer, more intense atmosphere.
2. PRO series are more professional, more pure tone and higher reduction.
3. The Hi-End suffix has a stronger sense of atmosphere and higher hearing tolerance.
4. Ultra and MAX represent the need for higher thrust combination, more rich sound.
SPA & STA Process Explanation:
SPA-Hi End / SPA-Pro: 3D Resin Printing + Precision Spraying
SPA-Hi End Ultra / SPA-Pro Ultra: Zinc Alloy Plating + CNC Post Treatment
SPA-Hi EndMax / SPA-ProMax: 5-axis CNC process for aeronautical grade aluminum
SPA series products are standard 0.78MM double pin LITZ coaxial cluster oxygen-free copper + silver-plated wire combination replaceable line.
STA series of products are standard with 0.78MM double pin oxygen-free copper + silver-plated wire combination replaceable line.
So many IEMs in the Silver Angel series:
Now I still haven’t exactly answered why there are so many. My final answer here is that The Fragrant Zither is exploring. Yep……..and part of this is maybe related to the recent success of Chinese manufacturers to proclaim their dominance of the IEM world. The quality I’m talking about got its start around 2013 and kept progressing. This hit peak sound around 2022 where companies were outdoing their previous quality and gaining mainstream sales quotas. Meaning right after Covid the market went crazy with quality. This coming of age meant that us into the development were astounded by this Golden Age. What this Golden Age represents is a maturity of techniques to make sound reproduction devices which fit into the ear. This coming of age meant that reviewers were not believed when they regularly gave IEMs that were provided for review solid 4.5 stars. This was coming as a disbelief, in that sure a reviewer gives great scores and the wash of IEMs keeps arriving at your doorstep. Only the thing is this wasn’t an exaggeration of sorts but a real life assessment of this quality.
What this means is the market got both saturated and of a profound quality of sound reproduction. Video of factories proved that this wasn’t chance or a fluke that would soon disappear, but that success was founded on basic understanding of sound reproduction and replay within the constraints of what was truly possible with a synthetic device attached to your ear.
As touched upon at the start of this review the 10mm and 6mm Dynamic Drivers are fully dependent on make-up. And the crazy part is that at the very start of this series I got a chance to hear the EarAcoustic STA-Hi End Universal IEM.
I’m starting this review in reference to the overall tone of the STA-Hi End. Why? Because it was the first of this series of TFZ IEM ideas. And now that I have heard 7 different IEMs all of different character and performance abilities, it needs to be said that I understand why Penon Audio sent me the STA-Hi End. At $49.90 it has a thinner idea of bass yet a clear and fun midrange. The next up to review was the $189.90 SPA-Hi-End Ultra. This was a study in contrast as the $49.90 STA-Hi End was mid-centric and weighed only 7 grams. Where the SPA-Hi-End Ultra was solid Zinc Alloy, not chrome coated resin, and the SPA-Hi-End Ultra weighed a whopping 14 grams each. Not only were the two very different, the STA-Hi End was faster as the 10mm and 6mm DDs could react faster. Where the 11.4mm DD inside the SPA-Hi-End Ultra came across both more cohesive and slightly slower in response times in bass character. Only transients are really what the SPA creations are about and what makes the SPA imaging so special.
This is again owed to the process taking place with IEM production and design. Meaning we are attempting to replay reality here. This 11.4mm full-range driver has an uncanny realism that made me emotionally feel it was the best I have heard, and I have tested many. Whereas hearing the SPA series takes you back to hearing a very natural and analog sound, spread-out into a bigger stage than what is possible with the STA series. Inside the 3 SPAs I have heard there are various replays of this treble which holds formation of treble replay into which things like cymbals are performed holding realism and texture, placement and creation beyond what I always thought was possible with a DD. You may not know this, but despite their off timbre, Hybrids are normally my favorite way to go.
EarAcoustic STA-Pro MAX:
So what about the EarAcoustic STA-Pro MAX? Well first off it is thicker sounding and warmer than any STA I have heard so far. That even with genres like EDM you are shown a faster sub-bass. Only this style of EarAcoustic STA-Pro MAX is new to me. How? The thing I first guessed was the EarAcoustic STA-Pro MAX is more like the SPA series than anything I have heard. This comes about simply by adding lower warmth and textures, these textures are really almost opposite of the thinner STA-Hi End. Now the way I see it, the TFZ company is using different driver make-up, because the driver size and shell ideas are identical here. But it is this filled in warmth that really started to grab hold of my emotions. Then the unthinkable happened……………
Yep, I got to thinking…….
Penon included a slightly downline Graphene cable with the retail version of the Penon Quattro. This included cable ended up super special in my Penon Quattro review. Then I rolled a few cables, and by chance this Rhodium-plated plug, Penon OSG (Graphene/Silver) arrived to take control of the playback. Meaning I could not get myself to separate this cable from the Penon Quattro. What was happening was the stage was expanded out which gave breathability to the 4 DDs the Quattro sports. This air was also reinforced by a darker/blacker background. Now the thing is Graphene is warmer than straight Silver, and creates a blacker backdrop of warmer yet still boosted midrange items. Meaning there may be color here, only it is just a tad, and I love that tad.
So what happened?
I got a thought:
What would happen if the OSG cable went and did the same magic to the EarAcoustic STA-Pro MAX? Here we have 2 DDs not 4, except it worked, it made the EarAcoustic STA-Pro MAX the best I ever heard it, so I had to include these results in this review, I mean how could I not?
Music:
Delain Apocalipse & Chill One Second 44.1kHz - 24bit Look, most of the time I don’t use this song on the album, but it came on randomly with use with the OSG cable, and I had to report on the experience.
Using Penon OSG cable in 4.4mm, EarAcoustic STA-Pro MAX, Sony WM1A DAP and SIMGOT Black wide-bore ear-tips, zero EQ.
Now the interesting thing is these SIMGOT AUDIO Black wide-bores are basically the same shape as one-half of the ear-tips you get with the EarAcoustic STA-Pro MAX. The only difference is that the clear silicone is slightly thinner, hence me grabbing the Blacks in the end. But I am so happy to see the use of this shape which is low profile and really a donut shape you can see in the photographs. Though the nozzle end is very close to the end of the ear-tips, plus the shape of the EarAcoustic STA-Pro MAX allows for these to work, for me anyways?
The song: To where here the guitars are so smooth, as smooth as overly distorted and boosted Symphonic (Female Fronted) Metal could be. But the EarAcoustic STA-Pro MAX has a groove and a musicality that maybe comes from the 2 drivers interacting? Where sure, we are not in the crystal clear part of town that the SPA series lives in, but the cost of admission is less.
So there is this timbre that is dead-on accurate due to no BAs used. That affects both the vocals here.........and the guitar. Where the drums are not as physical as what the SPA does 24/7, yet this lighter speed has an extra gift of pace, and I like that!
The main thing is that the EarAcoustic STA-Pro MAX is the darkest STA (so far) I have heard in the series. And if you're wondering if the stage is not quite as big as my original STA, the STA-Hi End. You would be right, only this is more filled in and less airy than the STA-Hi End. Yet this warmth is maybe what I always wanted.........as sure it is more money than the STA-Hi End, and more accessible and complete, more even toned and of a smoother character. Now this was actually a surprise as I thought the more money you throw at the STA line the more active treble you receive.
You see the EarAcoustic STA-Pro Universal IEM at $49.90 is brighter a little than the STA-HI End, which makes it the brightest of the STA series. Thus we took a turn here for smoothness with the STA-Pro MAX!
What about the music, what happens then? OK, both of these tracks showcase a style of tube amp distortion into which 100% (almost) of playback is represented. Now sure the vocals are clear and not distorted, but all the rest is.
Theater of Tragedy Assembly (Remastered) Episode 44.1 kHz - 24 bit
Ha, every once in a while I reach true synergy. The stuff to write about, yes? Here we bask in a bath of both warm tones, enough treble and upper midrange, yet the whole replay is basking in this very distorted and fun warm bath of extra harmonics. These harmonics are always in this song which makes it unique in my listening history.
Yet there is that special forgiving warmth that is so warm that you think it could cover-up details, only it only adds listenability.
This album is actually defining its very own sub-genre of metal having an industrial flair that came only with one other album by Theater of Tragedy. The best way to describe this is that even late at night we are maximizing the warmth and getting to a place where we just never want the music to stop. Yes, this is musicality over technicality, yet the technicalities are still there underneath it all. Promoting this fun sound that is unique and also so very right!
Packaging:
Included cable: The reason this cable section is near the end is because I have done the above and experienced the IEM enough already to roll-in the included cable to get an idea of what you have.
And basically this cable is leaving out a little stage, the included cable from a DAP gets you about 90% of the IEMs potential.
That means something, and if you really look at this cable, it's providing the perfect ear-hooks and stature of build. Plus this style of build does not tangle or act springy like it looks like it may do.
A lot of thought was put into the STA cable........remember a boatload of this exact cable is produced, offering easy to read right and left letters and all metal hardware.
There is strain relief at the 3.5mm plug and metal chin-cinch and metal barrels at the 2Pins. Also there is a fantastic memory to how the cable is wound, where it just stays wound and goes where you place it to be, never acting up or strange in demeanor. Also this may be a small item but important to take note, the chin cinch when moved stays right where you place it, while this may not mean much to some, some others will rejoice in this character.
Build: We already talked about the stealthy 6 grams piece of weight, we already talked about the chrome plated resin design, the smoky faceplates........you can’t miss.......those being embedded into Zinc Alloy.
What else is there to talk about? Probably the size being on the small side of life and direct contrast to the giant SPA series?
I mean there is a wearability here. And the fact that with phone use the EarAcoustic STA-Pro MAX could be an IEM you run down the street with?
Where I’m not running anywhere with the SPA series, at least the metal shelled ones! The fact that we have Aluminum nozzles hold onto ear-tips great. They are making boatloads of this STA model, so you know they are not experimenting with shape, plus the shape allows me to use my very shortest in length (wide-bore) ear-tip, Now coincidentally the included ear-tips are also very much like the Black silicone tips I am using for this review.
The only difference is the Black wide-bores are a little firmer in texture.
But there was a day when all I had was these clear silicone wide-bores, and to think now manufacturers are including them all the time, is amazing. Maybe I was onto something in the old days. Now if you desire a slightly narrower stage and more bass a second set of narrow bore ear-tips are included.
But my point is I can use my desired tips here, and that means the world.
A generic shape, with shark-fin. It just falls in place, also the semi-custom shape is designed from the human ear database.
The Human Ear Database compiles 1000s of public ear-shapes to arrive at a generic shape to fit all ears. As it turns out scanning software is used in conjunction with public CCTV cameras to identify people in public just like fingerprints. Though the kicker is people's inside tissue of the human ear is closer to being exactly the same, just not the outer ear.
Phone use you ask? Basically warm and friendly, with cool little extras put out by the midrange stage....................
This review is nearing the finish line. Meaning things start to get a little more laid back, after trying to get this set of EarAcoustic naming ideas correct and somewhat understandable.
Who in their right mind really wants to leave the house with an expensive IEM hooked to your phone? For one it is harder to hear the nuances performed by a TOTL when out-and-about. Plus you are mentally distracted to get the full-benefits of a TOTL during phone use.
So due to such realities an IEM just like the STA-Pro MAX starts to appear even more practical. Not to mention the weight in your ear being a practical 6 grams a piece. Then the chrome resin ends a selling factor here in cold climates. Then the fact that the STA-Pro MAX comes with a stain resilient cable that is built super well, as far as giving it heck. Yep, this combo of gear you getting really works in regards to a mobile IEM. So what about the sound here, from just a phone?
First off no one wants those finicky IEMs that sound thin from a phone anymore, no one wants them, they just sit on store shelves. Yep, manufactures totally understand the public only buy gear that sounds great from a phone!
There is just too much competition out there, and people who will use their phone in IEM shops to qualify the quality.
So as a product of phone use the first thing that gets you is the balance. To be sure the STA-Pro MAX does not offer the blackness of 3D background like you get from a DAP, but more importantly the tone is totally correct. So correct that even a jaded reviewer like myself could totally enjoy this reproduction. Yep, the days of bad sounding phone IEMs are now history, at least that has been my experience recently? Where you really are going to experience 85% of the potential here. And the thing is while I was fully smitten by the two more treble centric ideas in today's line-up, I can say here we are basking in a style of accessibility and warm fun, I don’t know another way to describe it. And………in many ways for those treble sensitive among us, this style of replay could even be found as superior. I review IEMs emotionally, so as long as I get big playback, count me in.
Conclusion:
This EarAcoustic STA-Pro MAX was ultimately surprising in the end. Why? Well it is not as expected. Where TFZ went and took a turn for more listenability and warmth. Where sure TFZ is covering all the bases here.
I can imagine someone in a shop going through the whole line of STAs, one-by-one and finally landing on the EarAcoustic STA-Pro MAX. The look of surprise on their face would be genuine and real. In fact while in the shop they would then sit down and remain quiet for a bit.
Taking in the charisma and charm, realizing that they may have to spend a little more than they planned on for an IEM today. But that with all the planets aligning, they would NEED to have this and NEED to take it home. That while it is rich and warm there are still enough details for the taking, emitted into this glorious stage that becomes fun and satisfying in the end. The end results of this review is I kept noticing the sub-bass, that while deep and punchy was also clear and not totally omnipresent, which gives the EarAcoustic STA-Pro MAX a style of audiophile bliss!
Disclaimer: The STA-Pro MAX has undergone 5 days of continuous burn-in.
Disclaimer: I want to thank Penon Audio for the love and for the STA-Pro MAX review sample.
Disclaimer: These are one person's ideas and concepts, your results may vary.
Equipment Used: Sony WM1A Walkman DAP MrWalkman Firmware 4.4mm and 3.5mm Sony WM1Z Walkman DAP MrWalkman Firmware 4.4mm and 3.5mm Sony TA-ZH1ES DAC/AMP Firmware 1.03 Electra Glide Audio Reference Glide-Reference Standard "Fatboy" Power Cord Sony Walkman Cradle BCR-NWH10 AudioQuest Carbon USB Samsung Phone 3.5mm output ifi GO bar Dongle 4.4mm and 3.5mm
