Clean Thespian

Introduction

FiiO has to be one of the most productive audio companies around and they are surely churning out products from the top to bottom in the price segment. Not all the products have been successful but certain products like the M17, BTR7, Q7 and many more have been a hit for their amazing performance. FiiO now has decided to take the plunge into a new flagship IEM to replace the FD7 and FH9 with a first implementation of electrostatic drivers for FiiO with the release of the FX15. The FX15 is equipped with 4 Sonion electrostatic drivers along with a single balanced armature and a dynamic driver making it a first tribrid by FiiO. RedApe Headphones Store has kindly sent us a pair for an honest take on their sound and we are grateful for the opportunity given. How will they fare in this saturated segment of the high fidelity electrostatic arena? We shall find out here.

Functions & Specifications

Before we start the review, here are the specifications of the FiiO FX15;

• Driver configuration: 4 x Sonion Electrostatic drivers, 1 x Knowles ED-29689 BA, 1 x 10 mm DLC dome DD
• Shell: Photosensitive resin 3D printed by HeyGears
• Impedance: 24 Ohms
• Frequency response: 20 Hz – 40 kHz
• Sensitivity: 103 dB/mW
• Cable: MMCX, high-purity 224-core sterling silver cable; interchangeable 3.5 mm and 4.4 mm modules

Retail Price & Where to Get

The FiiO FX15 can be purchased at Red Ape Headphones Store and they are the official distributor for FiiO in Malaysia

https://redape.my/

Shopee

invl.io/clk6d0k

Lazada

https://s.lazada.com.my/s.hrYAb

Packaging & Accessories

FiiO has been known to give their best in terms of packaging for their higher end products with a full accessorised package in a well designed box but they have decided to minimise the package of the FX15 by making it simpler but still pack all the necessities and more. They include the usual FiiO leather case, a box of HS19 eartips that consist of 12 pairs of various kinds of eartips, 3 pairs of FiiO HS18 eartips, 3 pairs of Spinfit CP145, FiiO LC-RD pro cable with a 4.4mm and 3.5mm plugs, FiiO magnetic clip, FiiO MMCX removal tool, a set of small brush and of course, the IEM itself. The cable itself will cost you around 15% of the cost of the FX15 which is priced at RM639 so the value of this package is actually quite good in terms of their accessories included.

Design

The FX15 has a thick body with a medium size shape but it is rather light, delicate and smoothly designed, parting away from FiiO’s usual edgy, techy design. They are inspired by the beauty of the Ginkgo tree, a sacred medicinal tree in China, with swirls of pink leaves lined on the faceplate encased in a semi translucent dark brown resin. The workmanship here is excellent as the resin is smooth, glossy and polished to perfection.

The shells are made from high quality resin that feels premium and comfortable. They are made in collaboration with HeyGears with a top of the line 3D DLP printing that is famous for their impeccable 3D printing products. On the nozzle, a metal mesh is fixed in place.

Inside the FX15 is packed with 3 types of driver, thus the name tribrid. They have a total of 4 Sonion electrostatic drivers for the high range, 1 Sonion ED-29689 for the mid-range and a 10mm diamond like carbon dynamic driver with FiiO’s patented turbo flute design in charge of the bass.

There is a rather large rectangular vent at the sides of the IEM for the dynamic driver and a switch on the top to disable the electrostatic driver for users to have a slightly darker presentation and also to feel the difference between the electrostatic drivers. I do feel the switch is quite redundant as users most probably will only use the on switch but it is still something for users to fiddle with.

The cable included is the latest cable from FiiO, the LC-RD Pro cable which consists of 224 high purity sterling silver cable that is braided tightly and they are soft and pliable. They came with a twist lock termination licensed from FABRILOUS which is a cable maker from China with 4.4mm and 3.5mm came in the box with angled metal MMCX connectors. They are a very clean and clear sounding cable with a thick midrange even when tested on my other IEMs.

Gears Used for Comparisons

Songs list

Tone and Presentation

The tone of the FX15 is a bright signature that has a mild U shaped sound for their emphasis on their high and lower range. They have a clinical sound that has superb technicalities especially in their details retrieval and resolution that sound vividly clear. They have a great neutral sound without any coloration present and the drivers work well with great cohesion giving a wide range of sound spectrum with good extension from end to end.

Soundstage

The FX15 is pretty good for their price as they are able to present sound with a wide soundstage along with a decent height in their sound. They have a great accuracy in their placement of sound that provides a spacious sound giving them a very accurate sound suitable for gaming and movies as well. The FX15 has a wide range of capabilities for their soundstage and is very enjoyable for live music performances for their airiness and wide sound that provides great holographic immersion into music. They possess a rather big headroom for their overall sound and do not sound boxy at all.

Separation and Timbre

Separation is superb on the FX15 and this is their main strength in my opinion as the sound from left to right is very well separated with no crosstalk present and they sound wide due to this strength. Timbre here is a breathy, slightly piercing and provides a clean, smooth tone that is very suitable for vocal based music and good for instrumentals. There is a very minor metallic hint in the timbre but I do find matching them with a warmer source remedies this minor issue. They are a little intense on the upper range but still manage to sound smooth for my listening.

Drivability

Rated at 32 ohm with a 103db sensitivity, they are not hard to drive but they need some power to perform at their best and they do need a slightly higher volume than usual for my listening. They are quite sensitive and will easily pick up noise when used on lower impedance output. The FX15 is quite revealing as it does show the flaws present in music and in the files you feed it and they do sound significantly better on higher resolution files but still acceptable for lower bitrates. They do scale up very well with good source and the electrostatic drivers do sound more present with a good source along with a deeper bass response.

The Bass (Low)

The bass that the FX15 possesses is a slightly lifted mid bass that has a decent amount of volume without overpowering issues staying true to a good dynamic driver bass that is natural and authoritative. Bass slam is rather tight with good texture in their overall response giving an organic and natural bass. Details and clarity here is good with a clean and clear presentation without any muddiness nor bleed present. The bass has great extension partly due to FiiO’s patented Turbo bass flute design that has an elongated pathway to increase the depth of the bass response. They are not suitable for bassheads as they aren’t strong enough to satisfy them, instead they are a good dynamic bass with adequate strength that sounds meaty with the right amount to be enjoyable. Sub-bass is great with a good extension along with a decent rumble and they can deliver when called upon on bass heavy tracks such as EDM, hip-hop or even jazz. Overall, I do find the bass performance great as they are dynamic sounding with the right amount of pace that gives music a pleasant boost without sounding unnatural.

The Mids

Midrange present in the FX15 is a neutral mids with a focus on the upper mids that gives them a brighter sound signature. The body here is leaning towards a thinner side but they aren’t overly thin to the point of making the music sound dry. Details and clarity here are superb with everything sounding crystal clear with subtle nuances audible. Macro and micro details are well presented giving a great transparency in their sound. Resolution here is amazing and they are one of the main strengths of the FX15 as they have the resolving capabilities to make music sound vividly great without any coloration and music does sound quite holographic. Vocals here are great, especially with female vocals, with clean vocals that have the brilliance and clarity but they do lack some lushness may sound a tad bit shouty on high pitch vocals partly due to their clinical sound. The midrange here actually tends to swerve towards a clinical side and they do lack warmth but in return, we do get a clean and clear midrange that is highly resolving without any coloration to produce the music as intended without altercation.

The Highs

Here is where the ‘piece de resistance’ of the FX15 lies, the high range. Equipped with 2 pieces of dual Sonion electrostatic drivers that are tuned specifically in tandem with the other drivers to showcase a true electrostatic flavour. They are certainly a boosted high range that might deter treble sensitive users out there but for me they are excellent and certainly very enjoyable for their crisp, sparkly and sweet high range that sound superbly liveful. Air is average but they do extend pretty well giving a wide range of frequency with a slow roll off. Details are packed to the brim with every single high note presented clearly with a great transparency and superb clarity typical of an electrostatic high range. They do sound a little aggressive and might incur some shout or peaks on high volumes so do take that in mind but for high intensity treble lovers, this might tickle your pickle. They do pick up some noise and buzz from some sources as they are quite sensitive but not majorly sensitive, so a good, clean source is recommended for this IEM. Overall, the FX15 does have the electrostatic high range performance and they are sublime for users like me as I do love some bite in the high range but treble sensitive users do beware as they might be a tad bit intense.

Comparisons

VS Dunu EST112

The Dunu EST112 is a similar tribrid IEM that houses 1 dynamic driver, 1 balanced armature but only a single dual Sonion electrostatic driver. They both have a rather similar tone that is slightly bright along with great technicalities. The FX15 does cost a little more than the asking price of the FX15 due to the extra electrostatic drivers in them.

High region of the FX15 is more present and has a crisper decay along with a slightly livelier presentation. Details are more evident but clarity is slightly better than the EST112. Extension and air is better on the FX15.

Midrange both have a similar neutral tone with the FX15 sounded a little brighter with a cleaner presentation. Clarity is better on the EST112 but the FX15 has better resolving capabilities. Vocals on the FX15 have the edge of sounding more accurate with more brilliance.

Bass quantity on the FX15 is bigger and they are deeper along with an extended sub-bass response. The bass of the EST112 is flatter with a leaner bass slam. Details and clarity of the bass is better on the FX15.

Soundstage on the FX15 is wider by a small margin with an airier presentation.

VS Moondrop A8

The 8 balanced armature IEM from Moondrop is certainly my favourite IEM as it is a well tuned flagship worthy sound. It has a very well balanced tone with a superb resolution that works well with any source. They are slightly cheaper than the FX15 but the FX15 does come with a more complete package.

Highs on the FX15 is a stronger type of highs that gives more presence along with an energetic and crisp presentation. Details and clarity is also better on the FX15 along with more textured and resolving highs but the A8 seems a tad bit smoother and natural.

Midrange of the A8 has a slight edge in resolution but clarity is better on the FX15. The A8 possesses a thicker tone but the FX15 sounds clearer and cleaner with a more transparent sound. Vocals on the FX15 sound livelier with a more brilliant presentation.

Bass on the FX15 has a tighter slam akin to a dynamic driver and they also extend better in their sub-bass with slightly better clarity but details are on par with the A8. The A8 has a better textured bass with a cleaner overall bass response.

Soundstage in the FX15 is wider, taller and airier with a bigger headroom as well but in a small margin.

Synergy

FiiO Q7

The flagship of FiiO’s portable DAC/amplifier the Q7 is a transportable powerhouse when it comes to driving power and they are packed with all the features like a swiss army knife. They have massive driving power and also a well controlled sound for in-ears and can bring out a lot of details for some IEM.

The bass the Q7 is able to give the FX15 is good as they sounded cleaner and clearer with an extension in their sub-bass region. Details and clarity are also improved giving a cleaner, more polished bass. It has also added some air into the bass response.

Midrange sounded slightly thicker and had better overall performance with vocal notes clearer and lusher with a more intimate presentation. The overall midrange sounded a little more accurate in terms of sound and they are wider in their frequency.

High range has been polished out a little and they seemed to be smoother while retaining their strong response. Their overall high range quality is intact while adding a little air in the mix.

Soundstage is expansive with a holographic and accurate placement while increasing their width along with airiness.

Hiby FC6

The R2R dongle from Hiby that has been garnering praises for their analogue sound that is warm and inviting. They are the top dongle from Hiby and they are a unique sounding dongle that has a strong output all in a small body.

Bass on the FX15 has the same quantity but clarity increases and they sounded tighter and clearer overall. Sub-bass deepened with better extension and a cleaner rumble.

Midrange has a more forward presentation with a thicker sound and they sound more fun. Clarity and details remain the same but they do seem to be toned down a little in their shout and peakiness.

High quantity remains the same but they seem to have leaner sparkle and they are smoother. High range has a slight extension with added air but they seem to lack the crunchy crisp sound on the FX15.

Soundstage has remained mostly the same with a slightly wider sound.

Who Is It For?

The FX15 is a treble head lover’s IEM indeed and for those who seek top class technicalities along with a superb electrostatic high range quality IEM, the FX15 might be the one. They are a highly resolving IEM with a crystal clear transparency that will reveal all flaws in music which is suitable for critical listeners. Vocal lovers will find the FX15 great as they are brilliant in their vocals providing a clean and lively presentation. Treble sensitive and bass heads might want to pass on this as they have an intense bright treble with a pure dynamic bass that is pure but not for headbangers. They are also not really suitable for gamers or monitoring as they are a little piercing due to their strong highs but can be remedied with the tuning switch to turn the electrostatic drivers off.

Final words

FiiO is on the mission here in introducing their first electrostatic IEM and also a flagship, and I do think they have succeeded here as the FX15 is a true performer when it comes to their technicalities and they are able to give a true electrostatic sound mixing with their dynamic bass and a clean midrange tuning. The package that comes with the FX15 is superb with the wide plethora of eartips and a high end silver cable along with a superb build quality that is very well polished is certainly something that is rarely seen in this price range. Though they are bright and intense in their high range, they are actually very enjoyable for users like me as I do love a strong bite of treble. The mid range to high end segment is truly crowded but the FX15 manage to stand out for their amazing performance. Kudos to FiiO and I do hope they will churn out something like this more in the future.

I would rate this product a 4 and half stars over 5 stars.

• Top class technicalities
• Perfect polished resin body with a beautiful design
• Great tuning with a bright tone
• Great overall details and clarity
• Superb separation
• Energetic dynamic bass
• Decent Sub-bass extension
• Clean and clear midrange
• Great brilliance in vocals
• Superb resolution and transparency
• Strong but controlled high range
• Evident electrostatic high range
• Above average soundstage
• Great LC-RD Pro cable

• Treble a little too intense
• Highs can be a little piercing
• Midrange do lack some body and lushness
• Fatigue on loud volume comes fast
• Bass aren’t the cleanest
• Switches redundant as it’s a waste to turn of the electrostatic drivers (subjective)
• Not suitable for monitoring purposes