The Aful Performer 8S is pebble-smooth and luxurious (just ignore the marketing)

When I first listen to an IEM and I like what I hear, I'm in no rush to find out why. I enjoy the mystery of everything clicking and savour the moments before I realise it's because of a textured bass, a forward midrange, or whatever the hell voodoo is going on in the treble. I'm just enjoying the music, and I want to postpone the analysis for as long as possible.

• Buy the Aful Performer 8S for $399 at Amazon

A case in point: the Aful Performer 8S. Everything sounded great, and I was loath to engage my brain or pull up the squiggly lines and find out why.

But fear not – this review isn’t based on vibes. I did eventually dig deep into why the Aful Performer 8s is, ultimately, a strong recommendation. And it turns out it’s because Aful likes to mess around with the upper midrange!

At $389, this is no budget IEM impulse purchase, and there are a couple of totally avoidable bloopers we have to talk about. But if you’re looking for a smooth-yet-never-boring IEM for all music libraries, I can highly recommend you try out the Aful Performer 8S.

Sound profile

When an IEM is described as ‘easy to listen to’, and something that 'can be enjoyed for hours on end’, I can’t help but read that as a low key slate. It’s not a massive leap from ‘inoffensive’ to ‘boring’. But the Performer 8S is a smooth yet clean, easy-listening yet exciting IEM that I can listen to for hours on end without getting bored for a second.

So how does Aful do it? Chop the head off the upper mids and add a small bass boost? Well, yeah... but there's a bit more to it than that!

Bass: The bass of the 8S is satisfying. I've heard bigger and badder bass, but this is not that. It hugs the Harman IE 2019 target around the sub bass, and piles more mid bass onto the target. Yet, to my ears, it sounds more measured than that would suggest.

According to the charts, this bass should punch way harder. And it definitely has impact, but because of the recessed upper mids and relatively relaxed treble, that bass leans more smooth than punchy. As with the sound profile as a whole, the bass is a mix of contradictions: smooth yet punchy, textured yet warm. Ultimately, it's fun and doesn't distract from the star of the show...

The midrange of the 8S was a real surprise. Once I'd made my listening notes, I fired up the Aful Performer 8S Squiglink to see its frequency response and, what?! It appears to be missing a chunk of upper midrange. A big chunk.

Now, I'm fairly new to EQing, but in my limited experience, whenever I hoon off around 5dB of anything, it rarely sounds like a masterful stroke of sonic genius. And yet, the Performer 8S midrange is the star of the show, coming across as rich and lush without vocals sounding too recessed. And it's thanks to that whopping gouge in the upper mids.

Instruments like guitars retain enough bite, and vocals, especially female vocals, seem purposefully positioned, not just pushed back.

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Things sound silky in the upper mids, and though that means vocals blend in more than not, there's still enough detail here, thanks to an elevation in the mid- and upper-treble. Neil Young's harmony-rich Tell Me Why, or the woodwind instruments in Me and My Friends' Before I Saw the Sea come across as measured, laid back and... addictive! I want to go back to it and hear it again, not because it's so transparent and clear that I'm picking up all the micro-details, but because it's soft and smooth and luxurious.

Previously when I've thought of a strong midrange, my mind went to the Sennheiser HD6 series template of forward vocals and meaty lower mids. The Performer 8S has that lower mid power, but lopping off the 3kHz takes the edge off things. The result is a new version of 'strong mids' that prioritises smoothness, yet doesn't sacrifice the heft of instruments.

Treble: Things are generally relaxed and well balanced here, for my ears. But there's air, there's detail, and there's excitement.

As mentioned, there's elevation in the mid- and upper-treble, which serves to add resolution to the mid and bass instruments, while the upper mids do that smoothing thing that they do.

Again, looking at the charts, the mid treble and air region may not look like it's working hard, but even the slightest elevation or nudge up here makes a greater impact, thanks to that soft focus on the upper midrange.

That all means that the technical performance – the perceived detail, the dynamics, the positioning of instruments (imaging) is all solid. Yet things remain smooth without getting too warm. This is not something I've personally encountered before, and I think it's great.

Comparisons & value

Comparisons: The Performer 8S doesn't sound like anything else I have in my collection, but it does share some traits. And as it's in the highly competitive $300/$400 range, it's definitely worth looking at similarly-priced alternatives.

First off is one of my favourite IEMs, the $309 Binary Acoustics EP321. These two IEMs have practically identical sub and mid bass on the measurements, and yet the EP321's bass comes across as more textured thanks to it having a more developed upper midrange, specifically around 3kHz.

Its bass sounds punchier and textured. There's more detail to the bouncing bass strings in Mac DeMarco's Heart to Heart. There's more air being moved for the lowest frequencies in Donald Fagen's Morph the Cat. That's not to say that the 8S's bass isn't impactful. It really is, but the IEM isn't tuned to give it the spotlight as it is with the EP321.

Elsewhere, the EP321 offers a far cleaner and clearer profile, with the treble really shining through. Definitely one to check out if you're after high resolution.

The $359 Xenns Tea Pro is another excellent IEM that goes for a warm rather than the 8S's smooth approach. The Tea Pro's bass has more heft and weight to it than the 8S, and it's also a touch brighter, while retaining that welcoming warmth in the lower midrange. The vocals are more upfront than the 8S.

The Tea Pro is more like the 8S than the EP321, and though they definitely don't sound the same, it would make more sense to me to choose between them, while I would buy both the 8S and the EP321, for their totally different approach.

However, if you're looking for one set, out of the 8S and the Tea Pro, I think I'd still go for the Tea Pro. It's got more detail, which is great, and I like the warmth, plus I can listen to it for just as long as the 8S. Both have nice, natural timbre, and they're both comfortable, with great cables. The Tea Pro's has swappable terminations, and no Marketing Monkey Business, so it wins for those reasons too.

When it comes to value, I'm afraid this is where the 8S drops half a star. It's $30 and $80 more expensive than the above IEMs, and although that would be fine when judged purely on sound, there are a couple of unforgivable things Aful got wrong with the making and marketing of the 8S...

Bass plugs? Really?!

There are three things that Aful muffed with the Performer 8S. One is the lack of swappable terminations, which I cover below in the Comparisons section.

Second, the IEM's passive radiator is marketed as a bass-boosting driver. It isn't.

Finally, there are fiddly ports that, we are told, if filled with tiny plugs will change the bass profile. They don't.

One of the biggest online critics of Aful's approach to both passive radiators and teeny tiny plug holes, is Chris (aka HawaiiBadBoy/HBB), from Bad Guy Good Audio Reviews. He notes that Aful markets the passive radiator as a driver when, by definition, it's a passive membrane driving absolutely nothing. In speakers, passive radiators are speaker cones with no magnet or voice coil that move in sympathy with the main woofer and actually boost the bass.

In IEMs, HBB says, passive radiators are dummy membranes that don't add any meaningful driver performance, making them a marketing play that needlessly oversteps into IEM design. And I agree. This is bad for customers.

As for the tiny bass plugs, I’m far too lazy to be fiddling with tiny vents and tiny plugs, to get absolutely no meaningful change in the sound. I can't imagine I'm alone on this.

I hate it when something unprovable is sold to me. And to get deep for a second, that's one of the things I hate about the audiophile hobby. There are so many amazing products, brands and passionate people involved. But there's also too many snake oil merchants hawking meaningless products with their magical poetry.

Ultimately, some IEMs already have switches that meaningfully change their sound profile, so why Aful went with the redundant microscopic butt plug solution baffles me.

And yet, I let all of this wash over me and just enjoy the frequency response.

Bottom line: If you're thinking of buying the Performer 8S, just be warned that this is an 8-driver IEM with one sound profile, and you should be golden.

Build & comfort

The build and comfort of the Aful Performer 8S is excellent. The build of the resin IEMs are smooth and well-shaped, but the real win here is their size. They're perfectly sized for my ears – not as small and awkward as the Kiwi Ears Halcyon, not as big and awkward as the Kiwi Ears Orchestra II (sorry Kiwi Ears!). They are, as Goldilocks famously put it, spot on.

I really like the case that they come with as, unlike every other one I’ve encountered, it magnetically closes shut, and there's not a zip in sight. This is really convenient and clever, and though it’s a small detail, it makes a meaningful difference.

The cable is both great and a massive let down. Its brown and grey colour fits perfectly with the 'Jupiter' vibes going on in the face plates. I like this type of medium thickness cable that never gets in the way of using the IEMs, doesn't give me any microphonics, and rolls away small enough into its small plastic home.

But there are no swappable terminations, and though you may not care about that – you'll select the termination you're most likely to use, 3.5mm or 4.4mm, and that's that – at $400, swappable terminations should come as standard. Many like the option of swapping from one to the other (especially IEM reviewers that want to use different inputs in their Luxsin X8 headphone DAC/Amp for comparisons).

Should you buy it?

I don't have one preferred sound profile – I'm a bit of a greedy bugger and I want a good version of every style of tuning. Basshead, crystal clear, warm, mid-forward... I want to hear it all.

And though I wasn't aware of this smooth-detailed take on things, I'll now happily add the Aful Performer 8S into my collection as a representative of preferred sound profiles. And yet, there are (non-tuning) issues to consider, and the fairly steep $389 price.

If you want a super detailed, bright IEM around $300, I'd go for Binary Acoustics EP321. If it's flat out warmth you crave, the Xenns Tea Pro is hard to beat.

But if you're intrigued by a smooth profile that isn't blunt or dull, and is instead dynamic and detailed, I highly recommend the Aful Performer 8S.