The F9 is a clearly V-shaped earphone with a slight emphasis on treble over bass. That said, mid-bass is present, providing a solid foundation for the rest of the sound while mids are clear and extended but less forward. Lower treble is spiked creating a rather uneven high-frequency presentation though this can be altered via eQ and tip choice. Of note, I did prefer the red tips to the black ones, they were more balanced overall while the black tips murdered bass definition and sounded a little less natural within the mids and treble. Foams further smooth off the high-end though I personally prefer silicones during daily use for their convenience. I’m also not a fan of eQ since it can be hard to create a reliable experience among multiple sources. Thus, the F9 sits in-between the more V-shaped Kinera H3 and more balanced Pinnacle P2 in terms of tuning, it is a tone that possesses enough balance for the majority of genres and one that many listeners will be familiar with.
Low frequencies are quite typical but mostly tasteful in tonality and the F9 has certainly proven to be one of the better technical performers I’ve heard around this price. Sub-bass is slightly elevated with good but not great extension, the F9 is on the looser side though impact is firm and rumble is easily discerned. They perform on a similar level to the Simgot EN700 Bass and Magaosi K3 Pro but fail to match the class-leading Kinera H3 and TFZ King in terms of overall extension and technical ability. This is followed by a modest mid-bass hump that grants the F9 with a fuller bass note but also a little bloat, and they are immediately less nuanced that the aforementioned H3 and the K3 HD as a result. Upper bass is more reserved but still well present and the F9 avoids bass spill or warming of its lower midrange as a result.
Bass texture and definition are both good though some details get buried beneath their mid-bass bloat. They also aren’t the tightest, most agile earphone around this price, easily outpaced by the competitors like the Pinnacle P2. During faster, more complex songs such as Earth, Wind & Fire’s “Boogie Wonderland”, the F9 can get a little lost and bass notes are somewhat one-note when compared to the more linear, more balanced King and Mini 2. Even the H3, which possesses greater bass emphasis, achieves a higher level of technicality through greater bass control. The F9 is certainly not a bad performer, quite the opposite, but the quality of their bass doesn’t quite match its driving emphasis within the sound. Still, those looking for great extension and impact combined with good detailing will find a very agreeable experience with the F9.
The first things that listeners will notice is the F9’s outstanding midrange clarity that grants vocals, both male and female, with a certain glossiness and extension. As a result, the F9 does not sound particularly natural and vocals do come off as a bit thin and oddly voiced but I can definitely see a lot of listeners enjoying this presentation; the F9 really flatters pop, acoustic and well compensates for the more veiled mastering of older albums. In terms of tone, the F9 is a brighter earphone with slightly recessed male vocals preceding rising emphasis into the upper mids and treble. However, male vocals still avoid a scooped sound and the F9’s midrange sounds pretty balanced in the majority of situations. As a result, the midrange of the F9 sounds more even than the H3 with similar overall linearity to the Pinnacle P2. My main complaint stems from a sizeable lower treble/upper midrange peak that can overly emphasise sibilance and saps smoothness from the midrange. Vocals often sound a little strident and instruments can come off as raspy.
However, from a technical standpoint, the F9 does impress, augmenting its clarity with excellent resolution that is among the highest I’ve heard around this price and even above it. The F9’s enhanced treble though not natural or refined, does notably aid space and extension of elements. Female vocals and strings, in particular, sound airy, delicate and separated making the F9 a great choice for acoustic. Courtney Barnett’s “Small Poppies” was flattered with exquisitely clear vocals, crisp guitars and great separation between elements. Furthermore, layering is very defined and the F9 is still surprisingly natural given its style of tuning. So those coming from warmer earphones like the Simgot En700 Bass might require some acclimatization to the F9’s thinner, clearer tones, however, they do reward with a mostly balanced and very technical listen.
The F9 has been getting a few criticisms regarding its aggressive, spiked treble response. And though everyone has differing levels tolerances, to my ears, highs aren’t harsh but they do get a bit overzealous. And this style of tuning certainly isn’t something we haven’t seen before, almost all Chi-Fi iems around this price have a bumpy treble response that either serves to heighten detail presentation or create the impression of air within a less extended response. It’s called compensation because on a superficial level, these iems sound similar to more technical models but lack the actual underlying technicality to present these elements in a natural fashion. The F9, thankfully doesn’t have to compensate for too much, its high-frequency response is nuanced, detailed and clear. Treble extension is very good but not absolute, the very highest details are still a little truncated though less so than competing models. Otherwise, middle treble is a little lifted while higher notes are a little smoother and more restrained to avoid outright harshness and fatigue.
And breaking that down a bit more reveals impressive underlying technicality. As aforementioned, lower treble is aggressive and notably accentuated though actual detail retrieval is good, roughly similar to models like the Pinnacle P2 and just below the H3 and K3 HD. That said, the F9 is very aggressive in its presentation, bringing every little nuance to the fore though without the forwardness of the King. This is augmented by very commendable resolution that grants treble elements with great clarity and immediacy. That said, texturing does suffer due to their thinner, spiked presentation that lacks the linearity to portray accurate instrument timbre. As a result, the F9 is a detailed, hyper clear earphone with nice air but also a somewhat artificial tone to instruments and the extent that this bothers the listeners will depend on preference and music taste.
Soundstage, Imaging and Separation –
As a result of their airier, hyper-crisp treble response, the F9 produces a very nice soundstage presentation that is among the best I’ve heard around this price, especially through a balanced connection. Width is great, extending to the periphery of the head and depth is notably more immersive than competing models. This is especially noticeable with vocals that extend exceptionally well on the F9. Imaging is good but not outstanding, directional cues are accurate and clear and instruments are easily located. Centre image to vocals is a bit hazy and diffuse and most elements tend to become pushed to the side of the soundstage. Separation is excellent due to their defined transition between lows, mids and highs in addition to enhanced clarity and resolution.
The F9 is one of the easier to drive earphones I’ve tested with a 28ohm impedance and 106dB sensitivity. Users shouldn’t want for more volume even from smartphones or portable MP3 players and those with any sort of dedicated DAP will have no trouble driving the F9 to potential. Due to its cool resolving tone, the F9 finds particularly strong synergy with warmer, more laid-back sources. I found the Chord Mojo and Shozy Alien+ both to provide extra smoothness and refinement to the F9’s excited sound in addition to a little extra body all without sacrificing detailing. My HTC 10 also provided a fine pairing with plenty of volume and the F9 was not overly affected by output impedance in my testing. Of course, the F9 can also take advantage of a balanced output, from my X7 II w/AM3 module, I noticed slightly more separation and greater bass weight and control as opposed to the regular 3.5mm output. It’s also possible that the cable itself is contributing as on the F5 in addition to greater driving power from these outputs.
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