The FiiO FH5S is a hybrid in-ear monitor (IEM) with a semi-open back design, built on the foundation of two dynamic drivers and two balanced armature drivers. One of the primary appeals of the FH5S is its versatile sound signature, which can be fine-tuned to individual preferences thanks to the inclusion of three tuning switches for bass, mids, and treble. In this comprehensive review, we will focus specifically on the frequency response of the FiiO FH5S, exploring how the different driver technologies interact, the impact of the tuning switches, and how the IEM handles various regions of the frequency spectrum.
Table of Contents
Overview of Frequency Response
Frequency response refers to how well an audio device reproduces different frequencies, from the lowest bass notes to the highest treble tones. Ideally, a flat frequency response means that all frequencies are reproduced equally, without any part of the spectrum being emphasized or recessed. However, different headphones and IEMs often have their own signature tuning that may enhance certain frequencies while rolling off others. This gives IEMs like the FiiO FH5S their unique sound character.
The FiiO FH5S, in particular, is known for having a “W-shaped” frequency response by default, meaning that the bass, midrange, and treble frequencies are all somewhat elevated compared to a more neutral reference tuning. This creates a dynamic and engaging sound that emphasizes different aspects of the music, especially when combined with the tuning switches, which provide subtle control over the sonic balance.
Low Frequencies (Bass)
The bass region of the frequency response spans from around 20 Hz to 250 Hz, covering sub-bass (20-60 Hz) and mid-bass (60-250 Hz). The FiiO FH5S is equipped with a 12mm beryllium-plated dynamic driver that handles the low frequencies, which is known for delivering punchy and fast bass with good control.
Sub-Bass (20-60 Hz)
The sub-bass on the FiiO FH5S is deep and impactful, especially when the bass tuning switch is activated. This switch elevates the sub-bass response, giving more weight to the lowest frequencies. Sub-bass notes are rendered with authority, making the FH5S a good choice for bass-heavy genres like electronic music, hip-hop, or modern pop where low-end presence is crucial. Even without the bass switch, the FH5S delivers a noticeable sub-bass rumble, though it’s slightly more controlled and not as overpowering as some other bass-centric IEMs.
With the bass switch deactivated, the sub-bass is still present, but the emphasis is reduced, resulting in a more balanced presentation. This can be preferable for genres like classical, jazz, or acoustic music, where too much sub-bass can overwhelm the mix.
Mid-Bass (60-250 Hz)
The mid-bass is where the FH5S delivers a solid punch. It provides a satisfying amount of “thump” that makes drums, bass guitars, and electronic kick drums sound dynamic and engaging. With the bass switch turned on, the mid-bass becomes more prominent, which can add warmth and richness to the overall sound signature. This makes the FH5S particularly enjoyable for rock, pop, and EDM, where mid-bass energy is essential for driving the rhythm and adding a sense of impact to the music.
One of the strengths of the FH5S’s bass response is its speed and control. While it provides ample punch, the beryllium-plated dynamic driver keeps the bass tight and avoids excessive bloom or muddiness that could bleed into the midrange. This ensures that the mid-bass does not overpower the rest of the frequency spectrum, maintaining clarity and separation between instruments.
Bass Tuning Switch
The bass tuning switch is one of the key features that make the FH5S stand out. When activated, it increases the overall bass presence, enhancing both sub-bass and mid-bass frequencies. This is particularly useful for listeners who enjoy a bass-heavy sound signature, but it can be deactivated for those who prefer a more balanced or neutral presentation.
The tuning switch doesn’t drastically change the bass response, but it does add about 3-4 dB of emphasis, which can be enough to make a noticeable difference in how the low end interacts with the rest of the mix. It’s a subtle but effective way to tailor the bass response to different genres or personal preferences.
Midrange Frequencies (Mids)
The midrange covers frequencies from approximately 250 Hz to 4,000 Hz, which includes most vocal and instrumental sounds. The FH5S uses a Knowles balanced armature driver for the mids, which is known for delivering excellent clarity and detail. The midrange is a crucial part of the frequency response, as it determines how vocals, guitars, pianos, and other midrange-focused instruments are rendered.
Lower Mids (250-1,000 Hz)
In the lower midrange, the FH5S maintains good body and warmth, especially when the midrange tuning switch is left in its default position. Instruments like guitars and pianos have a natural tone, and vocals are well-presented without sounding recessed. There’s enough warmth to give male vocals and lower-pitched instruments a full, rich sound, but the lower mids are not overly thick, which prevents the mix from becoming congested or muddy.
When the midrange tuning switch is activated, the lower mids are slightly pushed forward, giving a bit more presence and richness to this region. This can help bring vocals and instruments more to the forefront of the mix, especially in genres where midrange clarity and separation are important, such as classical, jazz, or acoustic music.
Upper Mids (1,000-4,000 Hz)
The upper midrange is where the FH5S truly shines. The Knowles balanced armature driver delivers excellent detail and resolution in this region, making vocals, strings, and higher-pitched instruments sound crisp and clear. Female vocals, in particular, are rendered with great transparency and brightness, and the FH5S does a good job of avoiding harshness or sibilance in the upper mids, even with the midrange switch activated.
The upper mids are naturally elevated in the FH5S’s default tuning, which gives the overall sound signature a sense of energy and immediacy. This can make the IEM sound more lively and engaging, especially with genres that rely on vocal clarity and midrange detail, such as pop, rock, and vocal-centric music.
Midrange Tuning Switch
The midrange tuning switch offers a subtle boost to both the lower and upper mids, giving a more forward and intimate presentation. This can be useful for bringing vocals and instruments to the front of the mix, especially in genres like classical or jazz, where midrange presence is key to achieving a realistic and natural soundstage.
With the midrange switch deactivated, the FH5S maintains a balanced and detailed midrange, but the emphasis is slightly reduced, giving more room for the bass and treble to shine. This creates a more laid-back sound signature that can be preferable for listeners who enjoy a more relaxed and neutral presentation.
High Frequencies (Treble)
The treble region spans from around 4,000 Hz to 20,000 Hz and covers the higher-pitched sounds like cymbals, hi-hats, and certain vocal harmonics. The FH5S uses a Knowles balanced armature driver specifically for the treble, which is designed to deliver clarity and sparkle in the high frequencies without sounding harsh or fatiguing.
Lower Treble (4,000-8,000 Hz)
The lower treble in the FH5S is well-extended and detailed, offering plenty of sparkle and clarity. Cymbals, hi-hats, and other high-frequency percussion instruments are crisp and well-defined, without being overly sharp or sibilant. The treble response adds a sense of air and brightness to the overall sound signature, making the FH5S feel open and spacious.
When the treble switch is activated, the lower treble is slightly enhanced, giving more presence and brilliance to the high frequencies. This can make the FH5S sound more detailed and revealing, especially with genres that rely on treble energy, such as electronic music, rock, or metal.
Upper Treble (8,000-20,000 Hz)
The upper treble on the FH5S extends well into the higher frequencies, providing a sense of air and space to the sound. The semi-open back design of the IEM also contributes to this, as it allows for a more expansive and airy soundstage compared to fully closed designs. The upper treble adds a subtle sense of sparkle and shimmer to the music, enhancing the perception of detail and resolution.
One of the strengths of the FH5S’s treble response is its ability to deliver high-frequency detail without becoming harsh or fatiguing. Even with the treble switch activated, the treble remains smooth and controlled, avoiding the common pitfalls of overly bright or sibilant treble that can cause listener fatigue over long listening sessions.
Treble Tuning Switch
The treble tuning switch is perhaps the most noticeable of the three tuning options, as it adds a slight but discernible boost to the entire treble region. When activated, the treble becomes more pronounced, adding more brilliance and air to the sound. This can be especially beneficial for listeners who prefer a brighter sound signature or for music that benefits from enhanced treble detail, such as orchestral or electronic genres.
When the treble switch is deactivated, the FH5S still delivers a good amount of treble energy, but the emphasis is slightly reduced, creating a more balanced and laid-back sound. This can be preferable for listeners who are sensitive to treble or for genres where a more relaxed high-frequency response is desirable.
Soundstage and Imaging
The FiiO FH5S, with its semi-open back design, offers an impressively wide and open soundstage for an in-ear monitor. This design allows sound to breathe more naturally, giving the listener a sense of space and depth that is often lacking in closed-back IEMs. The FH5S excels at placing instruments and sounds within the stereo field, making it easy to pinpoint their location. This is particularly noticeable in genres with complex arrangements, such as classical or orchestral music, where the layering of instruments can be easily distinguished.
The sense of width in the soundstage gives the FH5S an almost over-ear headphone-like feel, with sounds extending beyond the confines of the ear. This openness adds to the overall listening experience, making it more immersive and less congested. It’s an ideal characteristic for live recordings, ambient, and cinematic music, where the spatial presentation of the audio is crucial.
Imaging, or the ability to accurately place sounds within the soundstage, is another strong point of the FH5S. Instruments and vocals are sharply defined, with a clear separation between different elements of the mix. This clarity allows for a more engaging listening experience, as you can easily focus on individual instruments or vocal lines without them blending together.
Tuning Switches: Fine-Tuning the Frequency Response
One of the standout features of the FiiO FH5S is its tuning switch system, which allows users to adjust the frequency response to their personal preferences. There are three switches, each dedicated to a specific part of the frequency spectrum: bass, mids, and treble. These switches offer a subtle but noticeable adjustment to the sound signature, making the FH5S versatile and adaptable for a wide range of music genres and listening preferences.
Bass Switch
The bass switch increases the emphasis on the sub-bass and mid-bass regions, providing a deeper and more impactful low-end response. This is perfect for listeners who enjoy bass-heavy genres like EDM, hip-hop, or rock, where a strong bass presence is essential. The switch adds around 3-4 dB of boost in the bass frequencies, making the sound punchier and more energetic.
When deactivated, the bass response becomes more balanced and controlled, which is ideal for listeners who prefer a more neutral sound or for genres that don’t rely heavily on bass, such as classical or acoustic music. The ability to switch between these two bass profiles is a great feature for those who want flexibility in their listening experience.
Midrange Switch
The midrange switch brings the mids slightly forward, making vocals and midrange instruments more prominent in the mix. This is particularly useful for vocal-centric genres like pop, R&B, and classical, where the midrange clarity and presence are key to a natural and engaging sound. The switch doesn’t drastically alter the mids but gives them a slight boost that makes them more noticeable without overpowering other frequencies.
When the switch is off, the midrange remains clear and detailed, but with a more neutral presentation. This is ideal for listeners who prefer a more balanced sound signature where no part of the frequency spectrum is emphasized over the others. The midrange remains natural and smooth in both configurations, with excellent detail retrieval and separation.
Treble Switch
The treble switch adds a bit more sparkle and air to the high frequencies, enhancing the sense of detail and brightness in the sound. This is perfect for genres that benefit from a brighter sound, such as electronic, classical, and jazz, where the treble adds energy and definition to the music. The switch boosts the treble by about 3-4 dB, making cymbals, hi-hats, and high-pitched vocals more pronounced without becoming sibilant or harsh.
When deactivated, the treble response is slightly more laid-back, providing a smoother and less aggressive presentation. This is beneficial for listeners who are sensitive to treble or for those who prefer a more relaxed sound signature. Even without the treble boost, the FH5S retains excellent detail and resolution in the high frequencies.
Frequency Response Summary
- Bass (20 Hz – 250 Hz): The FH5S delivers deep, punchy bass with excellent control. The sub-bass is impactful, and the mid-bass adds warmth and energy to the sound. The bass switch allows for a subtle increase in low-end presence, catering to bass lovers without overwhelming the mix.
- Midrange (250 Hz – 4,000 Hz): The mids are clear, detailed, and well-balanced. The lower mids provide warmth and fullness, while the upper mids deliver clarity and transparency, particularly for vocals and midrange instruments. The midrange switch adds a slight boost, making vocals more forward and present.
- Treble (4,000 Hz – 20,000 Hz): The treble is bright and detailed without being harsh. The lower treble adds sparkle and definition, while the upper treble extends well into the higher frequencies, providing air and space. The treble switch adds a bit more brilliance, enhancing the sense of detail and clarity.
Conclusion
The FiiO FH5S is an impressive hybrid IEM with a well-executed frequency response that can be tailored to individual preferences thanks to its tuning switch system. The bass is deep and punchy, the mids are clear and natural, and the treble is bright and detailed without being fatiguing. The ability to fine-tune the frequency response makes the FH5S a versatile IEM that can excel across a wide range of music genres.
The semi-open back design contributes to an expansive soundstage and excellent imaging, making the FH5S a great choice for listeners who value spatial accuracy and instrument separation. Whether you’re a basshead, a treble lover, or someone who prefers a balanced sound signature, the FiiO FH5S offers a flexible listening experience that can adapt to your personal taste.
In terms of frequency response, the FH5S delivers a well-balanced and engaging sound that is sure to satisfy audiophiles and casual listeners alike. Its combination of dynamic and balanced armature drivers ensures that each part of the frequency spectrum is handled with precision and care, resulting in a cohesive and enjoyable listening experience.
If you’re in the market for a high-quality IEM with a customizable sound signature and a broad, spacious soundstage, the FiiO FH5S is a strong contender. With its excellent frequency response and versatile tuning options, it stands out as one of the best hybrid IEMs in its price range.