Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Bloggers and YouTubers have tried this product—so we've summarized their strongest opinions below. Links to full reviews follow.
What are hifi reviews useful for? (1) Identifying products you should demo in person at a dealer. (2) Learning which products reviewers unanimously praise as the best they've heard (this means they probably are legitimately great). (3) Identifying a product's attributes that satisfy your idiosyncratic needs and tastes. Beyond that, we often discount what reviewers say because they heap praise on most products—and are often apprehensive about publishing strong criticism or comparisons between products. Further, they seldom have more than a few products on-hand, often relying on their memories to compare past products. Always listen for yourself.
All
Tsuru Universals
reviews
Video Review
Manufacturer details
Features
Specifications
- Tuning Switch: StagexStudio built-in toggle for flat or bass-boosted sound
- Driver Details: Not explicitly specified on the page
- Included Accessories:
- 4-core Silver-Plated Copper (SPC) cable with 3.5 mm jack
- FATfreq hard case
- S/M/L silicone eartips
- IEM cleaning tool
- Warranty: 1-Year Limited Warranty
Description
FATfreq's flattest monitor to date - complete transparency and clinical performance. Our best-selling reference-tuned model.
Release Timeline
Manufacturer Site
Brand highlights
Taking a step back to look at reviewers' thoughts of the brand's entire lineup—not just this product—what stands out most is the following:
- FATfreq is recognized for its distinct "basshead" sound signature, delivering powerful and impactful bass responses, particularly in the sub-bass region, without sacrificing clarity in the mids and highs.
- They offer customizable sound profiles through interchangeable NOAH modules and tuning switches, allowing users to tailor the IEM's sound to their preferences.
- FATfreq IEMs often feature high driver counts and tribrid configurations, combining dynamic drivers, balanced armatures, and electrostatic tweeters to achieve a detailed and balanced sound.
Select products
Select product comparisons
Reference Pro SE Universals
- Positioning: A compact, studio-grade IEM reimagined with enhanced vocal clarity.
- Description: Offers an extra tweeter designed to bring out vocal transparency and detailed transient response in a balanced tonal presentation. Compared to the Musician Pro and Quantum models, it emphasizes clean studio reproduction over extended bass or planar dynamics, making it ideal for users focused on vocal performance and moderate budgets.
Musician Pro SE Universals
- Positioning: A bass-optimized IEM tuned for energetic performance and low-end impact.
- Description: Offers a uniquely tuned three-way crossover with an extra low-frequency driver that deepens bass without bleeding into mid registers. In comparison to the Reference Pro SE, it prioritizes vigorous bass output, while Quantum and flagship models deliver additional precision and modular control.
FATfreq x Effect Audio: Quantum
- Positioning: A high-performance IEM featuring innovative planar driver and modular tuning technology.
- Description: Offers a planar magnetic driver paired with detachable Noah modules and a premium Ares S II cable to ensure speed, accuracy, and fatigue-free clarity. Unlike the Reference and Musician models that focus on one tonal aspect, it provides enhanced customizability and balanced resolution.
Hayabusa Universals
- Positioning: A versatile flagship IEM designed for both live and studio applications with dual tuning options.
- Description: Offers dual-mode tuning via an analog bass toggle and incorporates additional super tweeter modules to enhance vocal detail and instrumental separation. Compared to the entry-level Reference and Musician series, it bridges the gap with creative tuning flexibility, while remaining more accessible than the ultra-premium Grand Maestro.
GRAND Maestro Universals
- Positioning: The ultimate high-end monitor featuring state-of-the-art customization and advanced acoustic technology.
- Description: Offers customizable NOAH modules, precisely engineered bass chambers, and a built-in vocal boost switch to deliver exceptional detail and tailored frequency response. In contrast to all other models in the lineup, it delivers superior build quality, expansive soundstage, and cutting-edge technology.
See All Products
Avg. Product Price
$501-$1,000
Used For Sale
0
Available (Scroll Down)
Brand Popularity
830
of 900+
Badges
Top 50 Brand
Top 250 Brand
Products Listed
31
Founding Year
2016
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Look inside the brand
Brand Page
Our interview with the brand
What are two key technological innovations or strong opinions that differ you from other brands?
What's your approach to customer support?
What are your favorite tracks for showcasing the strength of your products?
What other products pair best with yours?
From our interview with
.
Brand Page
Used
FATfreq
All of the Brand's Used Products
What if you spend more?
.png){kind=small}
FATfreq
Maestro SE Universals
2085
2085
/
4
Reviews
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
.svg)
Product Strengths
- Delivers an intense, brash, and enjoyable 'subwoofer madness' bass experience without overly compromising the midrange and treble
- Maintains balanced sound, ensuring vocals (especially female vocals) remain present and clear even with strong bass presence
- Offers solid imaging, instrument and vocal separation, and enough soundstage to avoid sounding claustrophobic
- Reproduces treble in a subtle, gentle, and smooth manner thanks to the EST drivers used, avoiding harshness and accentuating details with sufficient air
- Fits ears very well and isolates noise effectively due to its deep insertion and larger body
Product Considerations
- Can sound muddy on busy tracks
- The size might be uncomfortable for some users after a few hours of listening
- Requires quite a bit of power compared to other IEMs
- Detail sounded a touch on the softer side compared with other IEMs in the same price
- The stock cable is not good
Comparisons (according to reviewers)
- Vs Maestro Mini: Offers upgraded resolution and smoothness throughout compared to the Mini, especially in bass texture and resolution
- Vs IER-Z1R: Has more rumble, unlike the IER-Z1R, capturing spine-chilling bass experiences
- Vs U12T: The soundstage is better and bigger than U12T
- Vs U12T: Imaging, separation and general clarity are a bit better than U12T
Takeaway: The Maestro SE Universals are a top choice for bass enthusiasts who want excellent bass without sacrificing clarity in the mids and highs. With great imaging and a comfortable fit, they provide an immersive and enjoyable listening experience.
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
FATfreq
Hayabusa Custom IEM
1835
1835
/
1
Reviews
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
FATfreq
Maestro Custom IEM
2001
2001
/
1
Reviews
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
Our summary
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
.png){kind=small}
Campfire Audio
Astrolith
2199
2199
/
13
Reviews
Campfire Audio is a hifi headphone brand known for their Tuned Acoustic Expansion Chamber (TAEC) for balanced armatures and Solid Body Design that mounts drivers into a single 3D-printed "engine block" to improve tuning and reliability. The brand has pioneered several unique approaches, such as crossoverless dual-planar architecture, beryllium-PVD dynamic diaphragms, and 3D-printed ceramic acoustic structures. Their Andromeda model long held a reputation as a benchmark reference for hifi IEM performance.
Expand Details
Product Strengths
- Impressive technical performance, clarity, detail retrieval, and resolution due to its planar magnetic drivers.
- Features a new, comfortable, and ergonomic shell design that's also lightweight and durable.
- Includes two upgraded Time Stream Metal cables, providing both 3.5mm and 4.4mm terminations.
- Delivers a strong, extended bass response, with texture and speed, plus a nimble, airy top-end.
- Exhibits a spacious, wide, and holographic soundstage with good imaging and instrument separation.
Product Considerations
- Lower sensitivity might require a dedicated DAP or amplifier for optimal performance, and can sound anemic when paired with just a phone.
- Can be sensitive to source pairings, warmer DACs might wash out the mids and some pairings may bring out sibilance.
- Stock tips might not provide the best seal for everyone, and the stock tip selection is poor.
- Silicone eartips can make the treble sound harsh.
- The mirror-finished stainless steel faceplate is prone to fingerprints and smudges.
Comparisons (according to reviewers)
- Vs. Campfire Audio Bonneville: Astrolith has superior mids, clarity, detail and transparency, and better treble extension, articulation, and overall resolution.
- Vs 64 Audio Volür: Astrolith offers bigger bass and a more exciting presentation, as well as faster and more resolving sound, but Volür is more accurate overall.
- Vs. Oriolus Monachaa: Astrolith has a faster and more controlled bass with better texture, a more natural and realistic midrange with a fabulous timbre.
- Vs. Elysian Acoustic Labs Annihilator: Astrolith delivers a more robust and organic mid-range with realistic and natural timbre and more defined lower mids.
Takeaway: The Astrolith is a technically impressive IEM with a comfortable design that delivers a powerful and detailed sound. It could be a great pick for listeners who want high-end sound that can play all kinds of music well.
Video review
Our take on the brand
Campfire Audio is a hifi headphone brand known for their Tuned Acoustic Expansion Chamber (TAEC) for balanced armatures and Solid Body Design that mounts drivers into a single 3D-printed "engine block" to improve tuning and reliability. The brand has pioneered several unique approaches, such as crossoverless dual-planar architecture, beryllium-PVD dynamic diaphragms, and 3D-printed ceramic acoustic structures. Their Andromeda model long held a reputation as a benchmark reference for hifi IEM performance.
Product Page
Product Page
What competes at this price?
-(1)_compressed.png){kind=small}
FATfreq
FATfreq x Effect Audio
785
/
Released
2024
Experience a new level of control and precision with Quantum, a high-performance in-ear monitor featuring Planar Driver Technology and detachable Noah modules, allowing fine-tuned customization of Basscannon™ technology for a tailored low-frequency response. Engineered over a year of rigorous R&D, Quantum incorporates valuable feedback from discerning audiophiles & top-tier studio engineers, ensuring a sound signature that meets the highest industry standards.
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
Our Summary
Product Strengths
- Bass is a highlight, with excellent detail, clarity, punch, depth, and a natural sound, and the sub-bass is often emphasized
- Offers the ability to customize the sound through the use of interchangeable NOAA modules
- Technical performance is considered excellent, with good instrument separation, imaging, and layering
- The 'Super Stage' module creates a wide and immersive soundstage that reviewers found exceptional, setting it apart from other planar IEMs
- Smooth and energetic treble that is controlled and not harsh or fatiguing for most listeners
Product Considerations:
- Some reviewers found the comfort to be an issue due to the IEM's shape, especially for those with smaller ears
- One reviewer noted that the treble can sometimes sound grainy, particularly in the air region
- The stock accessories, particularly the eartips, are considered adequate, but not exceptional for the price point
- The included Effect Audio Ares S2 cable, while high quality, exhibits some memory and stiffness
- The industrial design/aesthetics were considered 'bland' or 'not pretty' by some reviewers
Comparisons (according to reviewers)
- Vs Letshuoer S15: Quantum is a bassier version of the S15
- Vs FATfreq MP145: Quantum is better in many areas, including sub-bass, vocals, and treble smoothness
- Vs Letshuoer SO-8: Quantum has better sub-bass depth and texture, but less mid-bass punch than the SO-8
- Vs Jomo Nautilus: The Jomo Nautilus has a lusher mid-range and zingier treble, while the Quantum offers better bass detail and soundstage
- Vs Ice Lab Prismatica: The Prismatica has a stronger mid-range and clearer instrument separation, while the Quantum has better imaging and immersion
- Vs 7th Acoustics Supernova: The Quantum has a larger bass slam, while both have clear midranges and fantastic imaging
Takeaway: The FATfreq x Effect Audio Quantum is a planar IEM with a bass-focused sound signature and a highly customizable soundstage, thanks to its interchangeable modules. It is a good option for those who want a planar IEM with impactful bass and a unique listening experience.
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
FATfreq
Musician Pro SE Custom IEM
667
/
Released
2022
A reimagined Musician Pro tuned for bass lovers. Accentuated 'V' curve with unrivaled bass extension and control. Coupled with a uniquely tuned three-way crossover, the M Pro SE features an extra low-frequency driver for a deeper, punchier bass line with zero-bleed into the mid registers.
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
Our Summary
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
FATfreq
Scarlet Mini Universals
667
/
Released
0
Experience raw, unadulterated power with the World's First 30dB sub-bass shelf, expertly controlled under 200Hz. FATfreq's proprietary tubeless hyper tweeter system provides stratospheric ultra-high extension and brilliance to 40kHz. Giving you the best of both worlds at incredible value and ergonomics.
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
Our Summary
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
FATfreq
Reference Pro Custom IEM
584
/
Released
Reference Pro offers textbook, reference-grade detail, and separation via three precision-tuned balanced armature drivers for the accuracy demanded while monitoring and mixing. The perfect tool for producers and singer-instrumentalists seeking to bring their mixes to the next level.
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Expand Details
Our Summary
Video review
Our take on the brand
FATfreq is a hifi audio brand best known for headphones that using Basscannon technology that delivers extreme sub-bass levels (20-30 dB below 200-250 Hz) without midrange bleed, along with NOAH swappable bass-chamber modules that let users tune sub-bass power versus control while reducing ear fatigue.
Product Page
Product Page
Thieaudio
Monarch MKIII
999
/
Released
2023
At their times, the original Monarch and the Monarch MKII set new standards for best-in-class performance in the global IEM industry. Not only did it redefine the price-to-performance bracket, but it forever changed how IEM manufacturers engineer and tune IEM's. Keeping with the times, the Monarch has undergone another revision to revamp its technical and tonal performance.
Thieaudio is a hifi audio brand best known for headphones with IMPACT2 technology—an in-ear "subwoofer" using two dynamic drivers in an isobaric chamber to boost bass power while keeping frequency constant—and dedicated sound bores to achieve studio-monitor layering and separation. The brand has established a benchmark reputation among reviewers for top-tier tonality at its price tier
Expand Details
Our Summary
Product Strengths
- Offers excellent midrange resolution, highlighting subtle details in instruments
- Features a safe yet exciting U-shaped tuning suitable for all genres
- Presents a dynamic and exciting sound signature, clear vocal performances, and a resolving staging performance
- The included cable is of high quality and features interchangeable plugs
- Has great audio reproduction accuracy and consistent audio delivery
Product Considerations
- The upper treble may be a little exaggerated for some listeners
- The shell is larger than average for a universal IEM, which may cause fit issues for some
- Stock ear tips are just okay
- Bass resolution could be better
- Does not have an integrated microphone, so a standalone mic is needed to take calls
Comparisons (according to reviewers)
- Vs. Monarch MKII: The MKIII has increased richness in its midrange and an upper treble exaggeration, offering a slightly U-shaped signature compared to the MkII's balanced profile
- Vs. Symphonium Helios: MkIII's midbass body contrasts Helios' dipped lower mids, MkIII has better overall resolution, but a more exaggerated treble
- Vs. 64 Audio U4s: The MkIII is better tuned compared to the U4s, with the U4s having a thicker midrange and weightier timbre
- Vs. MOONDROP x Crinacle DUSK: The THIEAUDIO have a more detailed treble range
- Vs. MOONDROP Blessing 3: The THIEAUDIO have a more elevated bass range
- Vs. TRUTHEAR x Crinacle ZERO: RED: The THIEAUDIO do a better job blocking out external noise and leak less audio
Takeaway: The Monarch MKIII is a well-tuned IEM that is great for all kinds of music and has excellent technical performance. If one is looking for a high-end IEM with a versatile sound, this could be a great choice.
Video review
Our take on the brand
Thieaudio is a hifi audio brand best known for headphones with IMPACT2 technology—an in-ear "subwoofer" using two dynamic drivers in an isobaric chamber to boost bass power while keeping frequency constant—and dedicated sound bores to achieve studio-monitor layering and separation. The brand has established a benchmark reputation among reviewers for top-tier tonality at its price tier
Product Page
Product Page
How to buy
Headphones
Search all hifi products
Explore our database of 10,000+ new and 25,000+ used hifi products.
