Fh25 3 Balanced Armature 1 Dynamic Driver IEMs

4 years of fine tuning
Forging ahead with the new reference grade hybrid HiFi IEMs iron HiFi headset

In 2018, FiiO implemented cutting-edge technologies such as the TRISHELL chassis, the S.Turbo acoustic design, and a 10mm polymer composite driver in the FH5, which gave listeners a rich yet detailed listening experience.

After the launch of the FH5, it was widely praised by users for its excellent deep bass and high resolving ability in an affordable package. It has been on the market for more than 50 months and is a testament to our dedication to great sound. The FH5 was also acknowledged by the industry – winning awards at the summer and winter 2019 VGP as well as in the 2020 VGP. In 2021, FiiO launched the FH5s/FH5s Pro, with replaceable filters that allowed for more sound customization by the user. This time around, we wanted to go back to the basics and take on the daunting challenge of bringing the sound quality of the FH series to new heights.

*VGP, standing for Visual Grand Prix, is an event organized by Japan’s Ongen Publishing. Beginning in 1984, over 30 years, the VGP has developed a reputation for being the "Oscars in the field of audio-visual equipment" widely recognized in Japan and all of Asia.

After four years of development and three generations of other product launches, countless experimentations and restarts, emerged an IEM that is the result of innovation after a lengthy development process. Through much objective data and subjective listening tests, FiiO not only developed a brand-new 10mm dynamic driver with a carbon-based diaphragm, but also combined it with other cutting edge technologies in the Fh25, which is designed to give you a musical experience as if you are there right with the artists.

Message from the engineers FiiO Present

"Among our products, the FH5 is a mid-range product with a sound signature that’s agreeable to many. It features a rich sound with lush vocals perfect for detail-rich classical and instrumental music.

In the four years and 3 generations of product launches after the launch of the FH5, we found that users wanted a brighter sound and even higher treble resolution but still maintaining some of the FH5 sound while being enjoyable for all kinds of music. Therefore, when designing the Fh25 we took the sound of the FH5 as a reference when tuning and developing the drivers in the Fh25. The lower frequencies are handled by our all-new 10mm dynamic driver with carbon-based diaphragm. The mid frequencies are produced by a custom Knowles ED BA driver, while the treble falls to the Knowles RAD for greatly improved transparency in the sound.

The bass, mids, and treble have been tuned in a way that allows the Fh25 to sound great with all genres of music. For those wanting to precisely dial in the sound of instrumental music focusing on particular instruments such as the piano, guitar, violin, etc. the Fh25 features interchangeable filters with distinctly different sounds."

Newly developed 10mm dynamic driver with carbon-based diaphragm

The FiiO development team chose to use carbon-based materials for the dynamic driver diaphragm, which allows for excellent transient performance. Carbon’s light weight, strong rigidity and high internal resistance means that the dynamic driver can quickly start and stop movements when responding to changes in the input signal. The high internal damping of the thousands of stacked and woven cross-fiber filaments of the carbon-based diaphragm means that the edge and the middle of the diaphragm can move together in the same direction quickly - minimizing breakup of the driver that results when different parts of the driver do not move in synchronization. This results in less distortion and ultimately clearer sound.

10mm Large dynamic driver
Tensile strength 9 times that of steel
At the same volume, 1/4 lighter than Beryllium

Custom Knowles BA drivers
As if you were at the concert

For mid frequencies, the Fh25 employs the custom Knowles ED BA drivers. These drivers work in conjunction with specially placed tuning holes in the shell of the Fh25 which allows for lusher vocals and a more musical sound.Treble is handled by 2 Knowles RAD BA drivers, which are capable of high treble resolution and capture every last detail in the music, for a truly airy sound. These drivers ensure that you get a listening experience as if you were there with the performing artists.

Custom notch filter
Richer sound for more pleasant listening

"For multi-driver hybrid earphones, combining them properly requires one to not only look at the drivers as a unit but also independently. We first tuned each driver separately as if they were on their own, and then scientifically combined the drivers together. This methodical process allowed us to reach our sonic goals for the Fh25." -FiiO IEMs R&D Center

The notch filter is specifically custom-made for the Fh25 and gives it its distinctive sound:

A Helmholtz resonator is designed to work with the mid- frequency ED drivers. When the sound wave is at a particular frequency that the Helmholtz resonator is designed to work with, the volume of sounds with this frequency is enhanced as the resonator concentrates and resonates that frequency. When looking at the frequency response curve, it can be seen that the response between 1 kHz and 4kHz has been improved, resulting in denser-sounding mids giving vocals and instruments more realism without sounding thin.

Additionally, the resonator is connected to a thin opening to eliminate any unwanted resonance peaks and overlapping frequencies produced by the different drivers, in order to achieve better coherency among the drivers while also eliminating sibilance. This is the notch filter technology employed in the Fh25.

S.Turbo patented design
Scientific HiFi with optimized frequency response

Balance between bass, mids, and treble as well as clarity are the ideal sound goals of many audiophiles, but this is easier said than done with multi-driver hybrid IEMs. This is because the multiple drivers naturally produce frequencies that overlap and interfere with each other. Thus, crossovers that divide the frequencies to be produced between the drivers are needed in order to achieve clear, coherent sound.

Thus, the RC circuit design is used to manage the crossover in the higher frequencies, with the treble driver with the higher resonant frequency being used as the high-pass filter. For managing crossover of the lower frequencies, the traditional low-pass filtering LC circuit requires components that take up too much space in the naturally small in-ear monitors. However, this did not stop FiiO from finding a solution to ensure bass frequencies produced by the drivers were of high quality. The development team worked with the understanding of the basic principle of sound waves. As these waves travel after being produced by the drivers, they will be attenuated when hitting other surfaces – the higher the frequency of the sound wave, the shorter the wavelength, and thus the faster the attenuation. The FiiO development team worked with this basic principle and developed the patented S.Turbo acoustic design*.

*Patent No: ZL2018211416279

To hit our mid and treble sound goals for the Fh25, we filter the higher frequencies produced by the bass driver in a low- pass filter, the S.Turbo acoustic design. This design reduces frequency response overlap between the bass and mid drivers for more coherency between the different drivers and a more balanced frequency response, for a cleaner and more natural sound.

Reboot your senses with a classical dragon, a fusion of classical and modern design

The Fh25 is a fresh reboot of in-ear monitor design, featuring a dragon scale motif in a moderately-sized oval shape that conforms and fits perfectly in the ear for greater comfort. The modern minimalistic lines transition smoothly into the classical dragon scale design elements, giving the Fh25 a lively robust look that reboots your conception of what an IEM can look like.

Aluminum alloy construction 5-axis CNC

The Fh25 features an aluminum alloy construction, which when combined with the dragon scale design elements allows the IEM to give off a unique, exquisite feel. Due to the small area of the Fh25’s faceplate, precise five-axis CNC machining ensures that each texture on the faceplate is suitably 3D and eye-catching. Specifically, fine cutter heads of 0.8mm diameter are used in the CNC machining process to ensure that the textures on the faceplate are both suitably attractive to the eye and luxurious feeling to the touch.

Come, let me be in charge of the sound with interchangeable sound filters

3 pairs of audio filters are included, each pair allowing for a different sound depending on the density of materials within the filter:

Red filter—— enhanced bass, for a bold sound
Black filter—— balanced sound, transparent and clear
Green filter—— exquisite treble, highly resolving

*Green filters are pre-installed, the other filters are on the included storage sheet

All-new FiiO HS18 ear tips

Included with the Fh25 are 3 pairs of the FiiO HS18 ear tips. Being only 0.4mm thick means the HS18 are extremely comfortable to wear. The HS18 also features a large opening, being the same size as the earphone nozzle, in order to minimize barriers between the earphone and eardrum for maximum detail and reduced high-frequency sound loss.

A great value high- quality cable

The Fh25 comes with a 152-wire silver-plated monocrystalline copper cable featuring 8 strands of Litz-braided wire. The Litz braiding specifically reduces the skin and proximity effects, leading to reduced eddy current losses and thus improved high-frequency resolution. Additionally, the audio plugs are swappable, and included are 3.5mm/4.4mm plugs.

*Interchangeable audio jack is officially licensed from the patent by FABRILOUS.

Abundant accessories

3.5mm swappable plug*1
4.4mm swappable plug*1
Treble filter*2 (green ring)
Balanced filter*2 (black ring)
Bass filter*2 (red ring)
MMCX tool*1
Carrying case HB1*1
Cleaning brush*1
Manual*1
HS18 ear tips*3 pairs (SML)
Balanced ear tips*3 pairs (SML)
Vocal ear tips*3 pairs (SML)
Bass ear tips*3 pairs (SML)
Dual-flange ear tips*2 pairs (M)
Foam ear tips*2 pairs (M)

*Balanced ear tips*1 pairs (M), Treble filter*2 (green ring), 3.5mm swappable plug*1 were pre-installed.

Specifications

Drivers: 1DD 3BA
Frequency response: 10Hz-40kHz
Impedance: 16Ω@1kHz
Sensitivity: 112dB/mW@1kHz
Audio plugs: 3.5/4.4mm plugs
Earphone connector: Expanded MMCX
Cable: 152 wires total high- purity silver-plated monocrystalline copper
Cable length: About 1.2m
Unit weight: About 6.6g (excluding cable)

Comparison

Model	Fh25	FH5S	FH5
Type	Hybrid	Hybrid	Hybrid
BA	3	2	3
DD	1	2	1
Frequency Response	10hz~40khz	10hz~40khz	15hz~40khz
Sensitivity	112dB/mW	106dB/mW	112dB/mW
Impedance	16Ω	40Ω	19Ω
Pins	MMCX	MMCX	MMCX
Pins	MMCX	MMCX	MMCX
Cable Length	≈120cm	≈120cm	≈120cm
Weight (per earbud)	≈6.6g	≈8.8g	≈8g
Color	black	silver/black	silver/black
Replaceable plugs	√	√	√

FiiO FH15 In-Ear Monitor - Discontinued