KB Ear F1

disclaimer:   The rep from Kinboofi recently asked if I had an interest in a new company named KB Ear and if I would like to try a new single BA in-ear from them.  I quickly said yes and Kinboofi provided the KB Ear F1 for review.  If you have an interest in these, they are available through Kinboofi’s amazon store at roughly the $35 price point.


Unboxing / Accessories:

The Box is a sliding cover design with picture, model and logo on front and details on the reverse.  Inside is foam tray with the earpieces and two set of tips showing.  A small box with the KB Ear logo sits below the foam and contains the remaining accessories.  A total of 6 sets of tips come with the F1.  3 resemble the KZ Starlines while the other 3 look more like spin-fits.  Having both narrow and wide bore tips provided is a nice touch, but some indication of the expected impact of using each tip style would be wise.  Typically the wide bores increase bass impact while the narrows are more neutral. We can assume the same here.



The F1 has kind of an odd shape and it takes a minute or two to get past that.  The shells are L shaped transparent acrylic with the nozzle exiting one end of the L and the mmcx connector at the opposite.   The entire body of the iem will fit on a US penny (sans Nozzle) just to give a size reference.     Fit is easy as the body is smaller than most and is somewhat reminiscent of the Campfire Comet.  Obviously materials and sounds are quite different, but shape lends to a similar fit.  Isolation is good as the tips sit fairly deep.   The F1 can be worn tip up or tip down with the one caveat being that if worn tip down, the vertical portion of the shell may be very snug to the side the head on larger ears.  They fit snugly on me which prevents them from shifting, but not tightly enough to be uncomfortable so I am probably about as large a person as the F1 will fit comfortably in tip down mode.



The F1 sports a single Bellsing 32257 balanced armature driver with an nominal impedance of 22Ω and a sensitivity of 105 dB/mW±2db.   The F1 is easy enough to drive from a phone and scales some, but not dramatically with higher power sources.     The Bellsing seems to be a fairly close clone of the Knowles 32257 which is a vented (damped vent) BA in thier RAB series which is designed for high efficiency systems in small enclosures.      The vent is clearly visible in the photos on the underside of the earpiece.   The BA is very small and is roughly the same size as the metal nozzle used.



The cable on the F1 is very similar to those of the TRN models and some of the recent Nicehck models as well.   The cable starts with a straight jack with a brushed aluminum casing.  A short strain relief exits the jack and then yields to a 4 wire braid of silver plated copper wire with a clear casing.  The braid runs to the splitter, also made of brushed aluminum and then exits as two wire twists to the earpieces.  The cable does not have earhooks to facilitate tip-up or tip-down wear.   The cable terminates in clear housings with mmcx connectors that appear to be gold plated.  The cable is fairly typical of items at the price range.




I’ll admit to expecting a single BA iem to be bass lacking. I’ll also admit, I was only half right.   Sub-bass is indeed quite limited, but mid-bass is better than anticipated with both good control and reasonable quantity.   There is a little perceptible bleed into the mids that gives the F1 a warm overall tone reminiscent of the Campfire comet while not being pronounced enough to hide much of the details.   I do think the Comet is more detailed than the F1, but tonally the two are more similar than not.



Mids are very much the focus of the F1 with a big push forward beginning as you come out of the bass range and plateauing at the true-mids.  That plateau stays level until we reach the lower treble where another rise kicks in.   Vocals are forward and well rendered although I found lower register vocals to be a bit more natural than their upper register counterparts.  Acoustic guitar is also well presented and a bit more realistic than its electric counterpart.   Detail and dynamic range are not class leading but not enclosing either.    The mids are one part of the F1 that KB ear got right for sure.



The lower treble has a bit of a spike at around the 3kHz mark, but while it contributes a bit of extra energy to the signature it is not so pronounced as to be fatiguing and with a slight adjustment of the EQ it can be brought back inline fairly easily.  I found that a -3dB at 3k worked for my ears and left enough energy to give vocals the desired presence without pulling too much life out of the signature.    Upper treble rolls-off rapidly above about 9kHz which provides enough top end to let snares have a satisfying crack but stops short of giving enough top end to really make cymbals sound realistic.   A bit more energy in the 10-12kHz range helps with the cymbal realism but even EQ is not much help here as the driver itself doesnt seem particularly sensitive in this respect.


Soundstage / Imaging:

Soundstage is wider than deep and only of average dimensions.   Instrument separation is directly related to how complex a track is.   The F1 does better with pop and rock than with orchestral pieces as the higher the instrument count, the more cramped the F1 can begin to feel.   Imaging is also limited as a result of the separation issues.   With less complex pieces, imaging is fairly accurate but when pieces start getting complicated, imaging is often crowded into the available space and feels congested and inaccurate.


Thoughts / Conclusion:

I was given two models of KB ears to review at basically the same moment by two different vendors.  Kinboofi provided the F1 while KB ear themselves sent me the Opal.  For two models coming from a new brand, they have little in common.  The cables and tip selection are very similar, but that is where it ends.  The Opal is a single dynamic driver in a teardrop shape, while the F1 being reviewed here is a L shaped single vented BA.  Ambitious to take on two different technologies and to start with a minimalist approach of using a single driver and tune the system rather than just adding another driver.   KB Ears should be applauded for that approach and I hope they will continue on that path.  A lot of multi-driver models lately are proving that it is harder to get right than the manufacturers anticipated and a return to sanity from the “How many BAs can you fit in a shell challenge” is nice to see.   The F1 has a lot of the issues that single BAs are typically known for, but manages to offset one (the low end roll-off) by use of a vented BA.   Overall, it represents a solid value at its price point for those looking for a mid-forward in-ear for rock and pop music.  Those who enjoy classical will probably want to hold off for now and see what KB Ear releases next.  If they continue to improve, it should be a good one.

KB Ear F1




Build Quality




Sound Quality

  • 6/10
    Bass - 6/10
  • 7/10
    Mids - 7/10
  • 5/10
    Treble - 5/10
  • 6/10
    Soundstage - 6/10
  • 5/10
    Imaging - 5/10


Pros: warm, non-fatiguing signature with forward mids.

Cons:  Early roll-off at both ends, can get congested on complex tracks.