Alright, cat's out of the bag. I don’t know anything about quantum mechanics—but that's not what you’re here for. Unless, of course, you are Chris Nolan and you're looking to make an Interstellar sequel. (If that’s you, Chris, message me privately.)
What you’re probably here for is FATfreq x Effect Audio’s new collaboration: Quantum. In April, Quantum officially launched, and we’ve been having a hard time keeping them on our shelves ever since. I first heard Quantum at CanJam NYC 2025, and was hooked right away. I loved the sound—as I tend to with most FATfreq IEMs—but mostly, I was fascinated by the design of the shell. Was this just a prototype? Why does it look so different, yet fit so well?
Turns out, that wasn’t a prototype. In all its uniqueness, that was the real deal. Since we’ve had Quantum here at Bloom for just over a month now, let’s get into just how unique this set is—especially at the sub-$800 price point—and try to decide if it’s right for your collection.
Build and Design
Quantum definitely turned some heads here at the office when we unboxed our demo unit and saw the final product. The shell is mostly made from a composite on the inside, where the nozzle sits, and has a stainless steel finish on the outside. Funnily enough, the outside of the shell almost looks like the “Beats by Dre” logo. Once you see it, you can’t unsee it…
Also on the outside is the Noah module system. Every Quantum comes with the new SuperStage Noah module, which we first saw with the Grand Maestro. In the first batch of Quantum, you receive the entire Noah set: the black “Power” module and the blue “Control” module. We’ll dive into this more later, but the sound design of this set can theoretically be customized in three different ways, depending on your personal preferences.
Quantum comes with the Ares S II upgrade cable as its stock cable. This is a premium copper Litz cable designed to offer a richer sub-bass impact, stronger low-mid punch, and forward-facing vocal presence. The Ares S II is UP-OCC copper with a central solid core, 26 AWG with 8 wires, and a 4.4mm balanced termination. One thing I believe anyone can appreciate is the premium feel: it’s about 4 feet in length and hits a happy medium—neither too thick nor too flimsy.
Quantum houses a 14.2mm ultra-fast planar magnetic driver with FATfreq’s proprietary ResoFlow Acoustic System. That’s right—it’s a planar. But Quantum is a little different from your stereotypical planar IEM. It’s not hard to drive and was built with portable use in mind. You can still get excellent performance from a dongle DAC or portable source and don’t need a powerful desktop setup to enjoy great results. That said, like most planar IEMs, it scales beautifully with a powerful system.
Sound
When talking about the sound, I want to offer both objective and subjective thoughts. I’ll be upfront: I really love this IEM. In fact, it’s probably my favorite release of 2025 so far. To stay transparent, I’ve been pairing Quantum with NiceHCK 07 eartips and doing most of my listening through the Topping D90 III Sabre DAC and Cayin HA-2A amp. For portable use, I’ve been running it off the DC-Elite connected to my iPhone. With that out of the way, let’s dig into how this set actually sounds.
The low end is emphasized pretty heavily, with the sub-bass regions taking priority over the low mids. The sub-bass is thick and heavy, but has a really fast response. On tracks like “Squabble Up” by Kendrick Lamar, where the production is heavily 808-focused, the response is tight—but don’t think this means it doesn’t have massive power. The sub-bass is immersive and acts like a soft, warm blanket.
On a track like “Breathe (In the Air)” by Pink Floyd, Quantum presents a tonally accurate bass guitar while also delivering a satisfying rumble just behind the punchy kick drum. Kick drums are short and sweet. On “Threshold” by Turnover, which lives on an album with intentionally massive drum sound, the kick drum has a solid presence. The whole drum kit sounds big, the snare is snappy and crisp, and the toms are full and rich. Quantum does a great job of providing low-end presence without making it the main focus. FATfreq is known for their impactful bass slams, and you definitely get a taste of that here—but it’s not quite on the same level as the subwoofer-styled Deuce.
Midrange is slightly recessed on Quantum, but not in a way that takes away from the music. I would say that this set has a pretty delicate, detailed midrange. There is a great sense of balance here, as opposed to some of FATfreq’s warmer tuned sets. On Weird Fishes / Arpeggi by Radiohead, the multiple electric guitar riffs are layered excellently, and have a crispy, soft tone to them. While I do think the separation could be a little bit stronger, the imaging on this set really shines on a song like this where there is a lot going on in specific right or left channels. Quantum does a great job of breaking all of that down for you and giving you a dead accurate representation of the producer's intentional vision.
Layering takes a huge step up with jazz songs with this set. On (Betsy’s Theme) by Bernard Herman (which is on the best movie soundtrack of all time, by the way), there is a ton of channel splitting with the instruments. The way that this track is designed production wise is very immersive, and Quantum helps bring that layer of immersion with its intense instrument placement. Not only do you get the sense of different parts in different channels, but there is another dimension of “behind you” or “in front of you” that really satisfies.
The treble regions act similarly to the low end regions in that they are short and sweet - which is a general theme for Quantum. It has great fundamentals, and the air region supports excellent reverb extension on vocals. On ethereal tracks like Seigfried by Frank Ocean, Frank's angelic voice is supported with some pretty heavy cathedral reverb, and Quantum handles it really well, adding a whole other dimension of immersion to this already immersive track. Plucks on acoustic guitar strings are soft and bright, and add a very soothing characteristic.
Let's talk about the Noah modules. The Superstage module, which we saw first for the first time with the Grand Maestro, does exactly what its name suggests. This module supports massive low end slams and a large, immersive soundstage. I found it to work well with some really well produced tracks like anything off of Dark Side of the Moon where it just transports you into that record. The Blue module provides mid range / treble precision, with forward facing vocal clarity for all you vocal enthusiasts. It helped a lot with bands like Whirr where the vocal presence is hidden a little bit. The black module provides a slight bass boost, making it great for hip hop and giving you more of that house FatFreq sound.
Comparison - Ice Lab Prismatica, 7th Acoustics Supernova
I find Quantum hard to compare to a lot of other IEMs due to its unique characteristics, value in its price bracket, and its build and design. However, the $800ish price bracket has a ton of great IEMs, so let's break down Quantum compared to some of our other most popular IEMs in this area, the Ice Lab Prismatica and 7th Acoustics Supernova.
Prismatica has a somewhat similar sound to the Quantum. It’s pretty balanced overall and the midrange on these 2 sets are what I find most similar. I think I would give a midrange advantage to Prismatica, where I find the instrumentation to be overall stronger and the separation between instruments more clear. Again, that was probably my main issue with Quantum. However I feel like the Quantum has better overall imaging and immersion. The key differences lie in the low end regions and treble regions, where the Quantum has much more of a low end impact and Prismatica has much clearer treble. In this price bracket, these are both premium sets that paid a lot of attention to the small details, like the cable and accessories. They are both great sets for 2 different people, though. I find them to be just as similar as they are different, and you could catch me listening to either of them on any given day.
Quantum reminds me a lot of Supernova. The upper midrange to the presence region is almost identical, up until that 8k peak on the Quantum. The graph would show differently, but I don’t think there are a ton of differences in sound when it comes to the bass regions. They both have snappy and fast responses, and don't overpower the rest of the frequencies. Still though, Quantum has a much larger bass slam than Supernova. The midrange on both these sets are clear and have fantastic imaging. I think that the immersion factor is stronger on the Quantum still, and the build quality on the Quantum takes the cake for me. Supernova is a classic IEM, and great in a lot of cases, but I think Quantum being the new kid on the block gives this great set a run for its money!
Concluding Thoughts
Overall, Quantum is the king of versatility in FATfreq's lineup, and is a precise, accurate IEM with massive low end impact, custom module tuning options, an upgrade cable out of the box, and a unique build that could be a great fit in anyone's IEM collection. If you don't really consider yourself a basshead, and have always been interested in a FATfreq set, this may be the one for you, as the low end is strong, but now quite as strong as the Deuce or the Scarlet mini levels. Furthermore, if you have a great desktop setup and are looking for an IEM that scales up with power, this would be a great set for you.
I appreciate the unique nature of Quantum, and I get a really great, comfortable seal, which may be surprising considering its unconventional shell design. I love the attention to detail and quality with the Ares S II cable. It really gives this set the premium feel that matches its sound signature. I spent most of my time listening to the SuperStage Module, but both blue and black modules really did impact the sound in a meaningful way, and I can see myself setting this up for different genres depending on what I'm in the mood to listen to. I’ve really enjoyed my time with Quantum, and know it will be in my steady listening rotation for a while. I think this set makes a strong case for being one of the strongest and most versatile sets in FATfreq’s lineup, and one of the best sets to come out in 2025. Hit us up in our live chat or shoot us an email if you have any questions about Quantum, we would be happy to chat more in depth and help in any way we can!
