EarAcoustic Audio SPA-Hi End MAX Universal IEM:
Redcarmoose Labs August 8th, 2025

We meet again, this time with the second only to the top of the SPA series, the SPA-Hi End MAX Universal IEM. Yep, at $289.90 the “MAX” as I’m going to call it has a 11.4mm full-range Dynamic Driver and Aviation Grade CNC shell. Really the $429.90 Limited Edition and the MAX have much in common. Starting with both IEMs having an 8 grams a piece weight. That and really the box-opening experience and accessories here are identical.

If you are worried about which one to get, I will do my best to show the comparisons here. Also for fun I’m throwing in the latest edition to the Silver Audio Series the new “Vocal Sweetness Amplified” or VSA-V1. Such a departure from the regular tenants of the 5 IEM STAR series, or 7 series SPARK series comes with added vocal tone.



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):

New Vocal Sweetness Amplified Series:
1) The VSA-V1:
2) The VSA-MAX:
3) The VSA-Mix:
4) The Astronaut: 
5) The VSA-V2:
6) The VSA-LTD:
7) The VSA-PM:

I want to briefly describe where the EarAcoustics VSA series goes, at least describe where I thought the VSA-V1 was slightly different from the SPA series.


EarAcoustic Audio VSA-V1 above:

From my recent VSA-V1 review posted:
"This VSA-V1 is advertised as a specific IEM, like a tool to be used in exact applications…….only that is not exactly what I found to be true. The VSA-V1 is in fact an all-rounder that I can welcome anyone who likes IEMs to get hold of. That in use the VSA-V1 seems to play anything you dish-up, and plays the music with better technicalities and a balanced tone, far better than you would guess from looking at the marketing script. This would be like being introduced to a new friend.............. that you felt would simply not work out for friendship due to preconceived notions about what was first visualized. Only (upon further meeting) find the person charming and sincere, offering a playful sparkle and an easygoing nature."


Left to right:
1) VSA-V1 14 grams each, 11.4mm DD $99.00
2) SPA-Hi End MAX 8 grams each, 11.4mm DD $289.90
3) SPA Limited Edition 8 grams each, 11.4mm DD $429.90

Side-by-sides:
All this talk about the latest edition of the VSA series. And if you read reviews others who have tested the upper limits of the VSA line (VSA-LTD) say there is not too much difference between the upper line VSA series and the SPA Limited Edition, except the VSA saves you money on a purchase. Don’t know if I will ever get a chance to hear the VSA-LTD, but I have the VSA-MAX in the mail to me.

Let’s get down to it:
All tests done with the Sony WM1A, Penon Apex cable and Penon PAC LStips.

VSA-V1:
Here bass is actually forward and more ample than the SPA-Hi End MAX. More contrasts….more stage and more vividness obtained. It is this excitement provided by the Pinna Gain that even starts to project the stage objects farther to the outskirts of the stage, in comparison to the Max. Now sure the Apex cable may have some work in this, but still…..I can access 4.4mm balanced from my DAP which allows for a better amp, as such all 3 IEMs today benefit equally. Is the VSA-V1 more entertaining? Maybe, maybe a little. Because it has you wonder because at times this extra level of VSA sonics could maybe come with “grain”..........but not here in this set-up, and not today. If you just read my opinion on the VSA-V1 in the introduction to this review, I value it highly.

Yet after a 3rd back and forth against the VSA-V1 we start to understand where this extra money went. That is fact the MAX is holding a smoother and slightly softer level of contrasts, and held inside those contrasts are slightly better realism, the cymbals hold a slightly softer touch, and while the bass is more reserved, that reservation is lacking nothing. Just a more cohesive and genuine idea of playback here. It is the MAX is no slouch and simply more polite in its demeanor. And the LE........well we will get to that!

SPA-Hi End MAX:
Funny that the bass with the MAX is a little tailored down as not as vibrant as the LE model. Also along with that comes a slightly sculptured down vocal presence to the tone. This could read like less thrills, only with the Apex cable and WM1A playback is still spacious and grand. Just not as forward in vocal positioning or vibrance, separation….etc, etc.


SPA Limited Edition:
A bigger stage than the VSA-V1 or MAX. A spread of details into the stance..................that shows just more. More size, more involvement and better details that come from the extra titanium work applied to the 11.4mm DD here. As such extra levels of separation and harmonics found inside those stratifications of sound.

More realness is the easy way to describe this effect. While the stage is bigger, there is also a slight fill-in of information inside of the imaging, in comparison to the VSA-V1 and MAX.

Verdict:
So to sum this difference up, at first the VSA-V1 really takes the cake. Meaning you hear this vocal push, and while the stage is relatively big, it is not as filled in or as fluid as the MAX and Limited Edition. There are unused spaces in-between note, that the MAX fills in more and the LE fills in even more. Where in the end there is a slight softness with the MAX that is charming, less vivid than the VSA-V1 sure, only vividness isn’t everything. Then the LE goes and adds that smoothness and softness while at the same time making the stage more filled-in and larger………ending in still the very best idea here today and worthy of the $429.90 asking price.

Verdict:
Remember these 11.4mm DD hold exceptional timbre and decays, and all three IEMs today showed that. That each IEM still held valuable balance in that neither of them were too bright or too bass heavy, just right here at Redcarmoose Labs. Remember even though the VSA-V1 had slightly more bass, that bass was not exactly of the quality of the MAX. That is you generate a bigger bass, at times you also promote lumbering and of a slight slowness not as noticeable with the MAX.


Top down:
1) Penon ASOS+X in 4.4mm Permanent Plug
2) Penon Apex in 4.4mm Copper Modular Plug
3) Included cable 3.5mm Permanent Plug

Cables:
Today I’m trying out the included cable in 3.5mm against the Penon ASOS+X in 4.4mm and the Penon Apex cable in 4.4mm. A funny thing happened last night where I took the MAX in preparation for this review, and combined it with another manufacturer's random cable. Running out the door I thought, well how bad can this cable be? Well to make it short, the MAX is totally dependent on cable stage and cable separation for its charms. Meaning I couldn’t wait to start this cable test in the AM, and using the Apex cable in the prior side-by-sides proved that the MAX IS cable dependent to a fault, and will scale-up with better cables.

All cable tests with Penon PAC LStips and Sony WM1A:

PENON ASOS+X:
This cable has been a favorite among the SPA series in the past. Why? Inherently full-range DDs yearn for the added separation and image isolation brought about due to the ASOS+X stage size. This cable additive in a way is making the DD more like a Hybrid design. Adding this air around instruments is the final solution for many a members take on what the downsides are with single-full range DD devices. Sure we have better timbre and decays, even better note-weight than what Hybrids pretty much do 24/7……only the two methods of making IEMs each have their pluses and minuses. 

ASOS+X:
HAHA, really this additive with the ASOS+X is making our MAX very much like the Limited Edition. That is almost all I can say? Bigger stage, more separation, reminding me how with the right cable and DAP I’m in Redcarmoose Heaven. I really am here. Jeeze, I had no idea this would be so grand of replay, and yes, miles better than the Apex cable in this situation. So to start, just like I thought, the treble and upper midrange have been separated and itemized into visibility.

Clarity through separation and sculpting. HA, I just found the ultimate cable for the MAX, the ultimate here. That any congestion or narrowness of stage is altered here, into the sunlight and clear as day. I’m shaking my head here, as I would have never guessed in a million years for this playback to be this good. The ASOS+X is $319.00 and yes, it is slightly more than the MAX, only this is so very good I would almost recommend this set-up over the LE edition. And can fully assure you that it would be better than the LE with the LE included cable!

Look, this is not a cable review, only if you have the MAX, just spend the money for the ASOS+X. Smoother, wider, taller, and closer and farther away imaging, just big imaging.

The silvery qualities about the ASOS+X at times will make a Hybrid stage too thin or the silver may diminish note-weight, only not with the DD………nope, it is world-class, at least with the WM1A with MrWalkman’s firmware it is!

Penon Apex cable:
Modular with the 4.4mm Copper plug additive.
Here we definitely have more authoritative playback. As such the Apex comes across more grounded and of a more sculpted bass idea. Then the upper midrange and treble seem to place air around the imaging, leading the playback to hold more separation will then more real imaging coming forward, out of clarity.

Where the ASOS+X is simply airy and of a dose more energy into both the midrange and treble, while still offering a smooth and detailed bass, the Apex bass is noticeably more, rounder, more image sculpted and coming from a less cluttered background.

Such ideas here create an added realism, though the main thing is while great, and still offering wonderful separation, the stage and midrange is more dense and less airy than the ASOS+X.

I mean you get what you pay for as far as cables go, with the extra money making the ASOS+X slightly more fluid and forgiving, broader and wider, and maybe even of better technicalities? Where this Apex cable is simply more real, less of a showboat of a cable, and the people who buy the Apex cable know this and want this.

The Included cable:
Funny as this is way better than the random cable I tossed on last night. The other cable is a cable that goes with the manufactures IEM, only it seems it was not so well-rounded to work with the MAX. There is no reason to list it here as there is a 1/1000 chance you at home will need to use this infamous cable with the MAX. Lol So anyway, yes, even in 3.5mm the included cable is a cable tested with the SPA line and included with every single SPA purchase.

If all you had was the included cable you get about 80-90% of the MAX potential. Only the included cable is actually a little like the Apex in that it is grounded and not adding to the upper midrange and treble paradise like the ASOS+X was. So in a strange way the ASOS+X was almost colored into silver energies taking over the town, adding separation and excitement. Yet here we have really regular pasteurized milk, and due to such charms is wholesome and good.



Build:
Coming in at a low-weight 8 grams, it is the silky aluminum feel and combined universal custom shape which adds so much to the fitment. I mean even with the heavy ASOS+X cable in place, fitment was special. Sure you can feel the difference of a 14 gram a piece shell in your hands, only that also seems to disappear in wearing? Flush 2Pins and correct nozzle length and angle. While plenty of breathability happens due to the giant nozzle sized breather off to the side of the shell, combined with a back vent. All and all the only drawback I can find here is they are a little of a fingerprint magnet.


The faceplates are beautiful and while they may take a while to get used to, in the end I feel most will accept this flashy look?  At least I gravitated later to liking (even loving) this look.

Music:
All music tests with Sony WM1A and ASOS+X cable with Penon PAC LStips.

E-Mantra
Stapanii Timpului
Ravenmocker (Original Mix)
44.1kHz - 16bit

Timestamps only pertain to digital file, not video.
Probably the main reason I chose this song again is how well it worked out in the VSA-V1 review I just wrote up. Truth to be told, yet we have even a smidge less of V response here, less bass and a little less treble. While the VSA-V1 is a vocal centric IEM, that is combined with the fact that it has excess bass action, and as such works with EDM, whose style is very much relying on bass energy to get its points across. So here with the ASOS+X I’m even more involved, call it emotion, call it immersion……..yes, immersion to the 10s. But not how you may expect this style of music playback. Meaning all is well and better than well, this is great……….only a tight and controlled bass yet totally separated and heard in the stage. That stage is embellished with added midrange imaging that is a little due to the MAX ability and the ASOS+X.

Here we have a warm and milky style of playback, which means that you could find that zone at any time day or night, and groove with what is going down here. At 06:17 we even hear sparkly up high notes reminiscent of a hybrid. And that my friends is the value here and what TFZ/EarAcoustic Audio has done to make this driver something special. At 06:47 there are cymbals which have been processed to almost sound like trash-can lids being hit. These deep centered weighted hits travel into their own unique space in the head-stage, out to the sides. At 07:09 the bass returns and I have to call it perfect, that while reserved it is physical yet fast, fun and holding drama.

Dead Can Dance
Within The Realm Of A Dying Sun
Summoning Of The Muse
88.2kHz - 24bit

The most beautiful part of using this song today is both the cohesiveness and the fact that the chimes at the start are well defined and clear, something that most DDs have issues with. Now to be honest they are not way out-front, yet held closer to home in frequency range, not as bell-like as I have ever heard, though the note-weight is on target. The decays here again are totally on target. And finally really we need to talk about vocalist Lisa Gerrard and the abilities presented by the MAX.

Now later in this write-up I will use has another female vocalist and a more modern recording to judge vocals with the MAX. With that said, this album is a bit touchy with DDs (due to smoothness) any way you approach it. That while heard, there are other DCD recordings which fully allow the MAX to broadcast Lisa’s vocals better. Though the redeeming factor is just how combined this sound is, it is not dull, or strident, but fully listenable and fun. That really we have almost a speaker in a room vibe here, with no tones out of place or taking unnatural notice. Though if I was to fault the MAX, at times it is on the edge of too smooth and even too forgiving.

Ghost
Skeletá
Peacefield
48kHz - 24bit

Timestamps only pertain to digital file, not video.
While this song shows the band Ghost going into almost Glam Metal territory. The opening is full of high-notes. Also it is reliant on contrasts to bring about the musical message. A choir, a single voice, all this before Tobias Forge makes his presence known with center and forward vocals. At 00:54 the guitar finally kicks in. Here we can witness a distorted guitar, yet really most would call this style of playback subdued, and there is nothing scathing or too much, if anything the guitar is almost set back in the mix, especially for what it is to the song at this point. At 01:04 the beat and vocals arrive. And to truly judge the MAX, the vocals here are just forward enough to make it work out, yet you can also tell that this is where the EarAcoustic Audio’s Limited Edition becomes more complete. More vibrant and more resolving.

Yet at the same time this is perfectly balanced and not really doing anything wrong. At 01:34 we really have the start of the song, and they play with our emotions this way, to slowly add the dimensions in tone, until we have arrived at power chords. The slight drum accent at 01:45 is special in that it is fast and imagined into its own zone. Probably the most valuable asset here is simply the correctness of tone and timbre, that as the song moves along we are romanced into enjoyment, enjoyment of this simple thing called music listening.


Delain
Apocalypse & Chill
Chemical Redemption
44.1kHz - 24bit

This song has an unusual guitar timbre which I would have never guessed. This truth I would have never guessed, as it is not necessarily bad, only slightly darker than expected. This goes to kinda show what is up with the MAX. That while doing most music great with all those charms that DDs are known for at times when you want more drama and a little less laid-back-ness, the MAX may be too calm. That is where switching over to the Limited Edition went and added just a touch of extra upper midrange, and (while still holding DD demeanor) launched Charlotte Wessels vocals to a slightly better perspective, showcasing slightly better separations and contrasts here. Though amongst it all is this connected stage and togetherness that holds true for the entire SPA line-up.



Packaging:

Conclusion:
We had fun today. We did comparisons between the Silver Angel Series Limited Edition, the Silver Angel Series VSA-V1 and the SPA-Hi End MAX. We used the included cable as well as the Penon ASOS+X and Penon Apex cable. We played tunes and tried to learn where the MAX did the very best, and where due to nothing being perfect it was a little less. What I can tell you is that the MAX is one of my most favorite of the Silver Angel Series and will go into regular use here at Redcarmoose Labs. That while not being the most pricey, the MAX performs a generous stage filled with careful imaging and separation. Really to sum this sound up would be to call it a balanced and warm yet a fun and involving tone. Perfect to relax to after a day of work, or fully involved to take notice of your best music when wanted. The build is amazing, as well as the included box opening experience. The fitment is in one word luxurious……..what more would you want?

Shopping link: https://keephifi.com/discount/tfz-blog?redirect=%2Fcollections%2Fearacoustic-audioDisclaimer:
The EarAcoustic Audio SPA-Hi End MAX Universal IEM has had 7 days of burn-in.

Disclaimer:
I want to thank Penon Audio for the love and for the EarAcoustic Audio SPA-Hi End MAX Universal IEM 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
Sony WM1Z Walkman DAP MrWalkman Firmware 4.4mm
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