KZ D-Fi with 4 tuning switch 1x10mm DD

It’s been a while since I have last reviewed a pair of KZ IEMs. Almost three years, to be exact. I missed out on quite a few KZ models in that period but from a tuning perspective, they were mostly more of the same.

However, around the end of 2022, KZ began to churn out some interesting models in terms of tuning. That departure comes full-circle with the KZ D-Fi, which is aptly named in the sense that the tuning “defies” the typical KZ house-sound (V-shaped, in other words).

Now, this is not a radical departure for KZ and some of their “signature” sound characteristics still seep through the cracks. However, the 4-way switch is a novelty in the budget segment, and the dynamic driver promises performance beyond the price point.

That’s a promise I hear often, but very few manage to keep it. Can the D-Fi be the one to follow through?

Note: the ratings given will be subjective to the price tier. KZ provided the D-Fi for evaluation.
This review originally appeared on Audioreviews.
Sources used: Questyle CMA Twelve Master
Price, while reviewed: $33. Can be bought from KZ’s official store.

PACKAGING AND ACCESSORIES​

KZ rarely focuses on the packaging and presentation and in the budget segment I applaud this move. I do wish that less plastic was used in the packaging for environmental reasons.



The stock accessories are good enough to get you going. The stock cable is an SPC affair that gets the job done. Stock tips are decent but tip-rolling may help in controlling the bass, for example.

BUILD QUALITY​

Phenomenal, in one word. The metal shell is dense and I find the face-plate visually appealing. The review unit is the one with the tuning switches and I recommend getting this one because the price premium is absolutely worth it.



The switches are somewhat fiddly to operate with the fingernails, so KZ supplies a SIM-card tool to make the task easier. There is one vent on the face-plate and one on the inner-side of the IEMs. The 2-pin ports stick out of the shell – a choice I am not a fan of, but it is what it is.

COMFORT, ISOLATION, AND FIT​

While the shells are shaped ergonomically, the added weight can be a bit of a bother for long listening sessions. Other than that, no qualms with the comfort. Isolation is above-average and becomes drastically better with foam tips.

SOURCE AND EARTIPS​

The D-Fi are very easy to drive and on my desktop Questyle CMA Twelve Master, I “over-drove” them when using standard gain, so I had to use low gain while testing them.

DRIVER SETUP​

KZ D-Fi have a 10mm single dynamic driver with the usual “dual-cavity”, “dual magnetic circuit” bonanzas. The driver performs well for the price, but the most interesting part for me is the Zobel network-based crossover-circuit. I do not recall seeing such tuning methods in any of the IEMs in the past… decade?

From what I can gather, the Zobel network is used to “attenuate” the frequencies by approx. 5 dB. When all the switches are down (default position), the entire FR remains same but things go “quieter”. Flicking each of the first three switches (in conjunction with the other one) adds 1dB of sub-bass boost from 50Hz downward.



When all four switches are engaged, the networks does not attenuate the frequencies anymore and you get a noticeable increase in loudness. A clever mechanism indeed. Keeping only switch four engaged, meanwhile, increases the loudness of the treble region by a couple dBs.

TONALITY AND TECHNICALITIES​

KZ D-Fi have an upper-midrange forward tuning. The lower-mids still sound recessed but the focus on the upper-midrange is what you notice the most. The overall tuning is rather energetic.



Sub-bass rumble is strong and noticeable even around 25Hz. Mid-bass texture is lacking though, so snare hits do not quite have the timbral characteristics you’d expect.

The mids are affected by the upper-midrange glare. It does not seem too much at the graph at first, but the upper-mids can get intense in soaring female vocals or while playing certain guitar riffs. As a side-effect, male vocals can sound somewhat “hollow” in some tracks.

Upper treble lacks airiness. Treble is mostly there due to a noticeable 8kHz peak. Then the treble rolls off past 13kHz or so. Given the budget nature, I think this performance is acceptable despite the hit on perceived “resolution”.

Despite the treble roll-off, initially, there is some “wow factor” due to the hyper-energetic tuning. Things can get fatiguing though if you are sensitive to boosted upper-mids.

Stage is narrow. Imaging is good for the price though some of the peers do it better. Macrodynamic punch is strong, while mIcrodynamics are lacking.

SELECT COMPARISONS​

It’s a bit difficult to make “Apples vs Apples” comparisons when it comes to the D-Fi because, let’s face it – there isn’t another option in this price range that has tuning switches.

Putting the novelty aside and only focusing on the sound quality, Final E1000 are better tuned across the board, even though they lack the bass rumble of the D-Fi, and the build is nowhere near as reassuring.

The BLON BL-05S, meanwhile, have a gaudy color scheme that hides the overall great sound, which is better than the D-Fi in terms of tonality and technicalities. They need changing the cable and tips, however, and the price tag can go well beyond USD$50 after that fact.

CONCLUDING REMARKS​

KZ D-Fi are the odd ones out in the budget segment. The tuning is closer to the current “trends” of boosting the upper-midrange and dialing down the bass, while the tuning switches can be novel enough for many to warrant a purchase. I am not a fan of the shoutiness, nor the lack of mid-bass texture and warmth. Then again, the pricing is fairly competitive.

I do wish KZ further tones down the upper-mids in the next release, and perhaps focus on making the sound slightly warmer and more inviting. Once that happens, I may finally have found a pair of KZ IEMs that can stay in the collection for future comparisons.

DISCLAIMER

I would like to thank KZ for furnishing this unit. It can be gotten here: https://kz-audio.com/kz-d-fi.html (no affliate links).




SPECIFICATIONS

• Driver configuration: 10 mm dual-magnet dynamic driver
• Impedance: 23.5 Ω (standard version), 29 Ω - 48 Ω (tuning switch version)
• Frequency response: 7 Hz - 45 kHz
• Sensitivity: 110
• Cable: 3.5 mm, 0.75 mm 2-pin high-purity silver-plated cable

Two variants of the D-Fi are available during ordering - a cheaper non-tunable version (~ USD$25-30) and one with tuning switches for about $5 more. One can also opt for a mic or non-mic version.


ACCESSORIES



Other than the IEM, the following are included:

• 1 pair of foam tips
• 3 pairs of wide-bore silicone ear tips
• 3 pairs of narrow-bore silicone ear tips
• Cable
• Card pin

The accessories are acceptable for a budget-priced set, and I won’t nitpick on the lack of a carrying case.



KZ's QC curse has come home to roost, with an odd number of silicone tips provided! The white narrow-bore tips boost bass at the expense of a compressed soundstage, whereas the wide-bore gray ones increase the higher-end and expand the soundstage. The foam tips give the best passive isolation, though these tame the treble.

Don’t lose the included card pin! It is essential for flicking the switches on the tunable D-Fi!




The silver-plated stock cable is tangly and thin, with microphonics in abundance. It doesn’t even have a chin cinch! I guess this is expected for something this cheap, and it is no biggie sourcing aftermarket cables. The D-Fi utilize a 2-pin 0.75 mm connector instead of the more common 0.78 mm terminal, but these 0.78 mm aftermarket cables should still fit it.

To not add aftermarket confounders, which may affect the sound, I completed the following review with the stock wide-bore ear tips and stock cable.


BUILD/COMFORT

The housings are teardrop shaped, with an elegant asymmetrical pattern on the faceplate, and are tasteful compared to the usual run-of-the-mill budget gear. We have the tuning switch board found on the sides of the IEM.




Despite looking chunky, the D-Fi has superb ergonomics coupled with a light weight, without awkward protrusions. I have no issues using it for longer listening sessions.




I did not find driver flex, but this may depend on the ear tips used and your ear anatomy. Isolation is below average because of the vented housing.


INTERNALS

The D-Fi employs a 10mm dual magnetic DD setup. KZ advertises that this generates a magnetic field of two magnets instead of the regular one, thus improving transients. A Zobel network circuit - only available in the tunable model of the D-Fi - is installed to nullify the effects of inductance and capacitance via a hub of resistor-capacitor networks.



The tuning switches are the selling point of this IEM. The first three switches modify the bass, whereas the fourth handles the upper frequencies. Manipulating the switches is as easy as pie with the provided card pin; they lock with a satisfying click.


DRIVABILITY

I tested the KZ D-Fi with the following sources:
- Apple dongle
- Cayin RU7
- Colorfly CDA M1 DAC/AMP dongle
- Creative Sound Blaster X5
- E1DA DAC/AMP dongle
- Hiby R3 Pro Saber 2022 DAP
- Khadas Tone Board -> Schiit Asgard 3 amp
- Khadas Tone Board -> Topping L30 amp
- Questyle M15 DAC/AMP dongle
- Sony Walkman NW A-55 DAP (Walkman One WM1Z Plus v2 Mod)
- Sony Walkman NW A-55 DAP (Walkman One Neutral Mod)
- Sony Walkman NW WM1A DAP (Walkman One WM1Z Plus v2 Mod)
- Smartphone

Depending on which switch setting is in play, the impedance changes. In general, the D-Fi is moderately easy to drive even on the higher impedance settings, though amplification is useful to scale. Due to its high sensitivity, the D-Fi may hiss with sources with poor noise floor control.


SOUND & TECHNICALITIES

Graphs of the KZ D-Fi on various tuning switch settings. 8 kHz is a coupler artefact peak.

The D-Fi has a tonality that is warm neutral with a sub-bass boost. It is more akin to a Moondrop FR - it is truly the antithesis of a run-of-the-mill KZ set! KZ enthusiasts may find the D-Fi undynamic and dull compared to the usual head-banging fun they are familiar with.

KZ’s marketing materials trumpet that the four tuning switches can provide sixteen contrasting permutations. The tuning switches make subtle differences at best, with only a 4 dB difference in bass between the most extreme of presentations and the rest of the profiles falling in between. The cheaper non-tunable version of the D-Fi corresponds to the “all switches down config” - i.e., the least bassy setting of the above graphs.

Timbral accuracy is very natural for vocals and acoustic instruments, in keeping with the D-Fi’s single DD roots.

The D-Fi is subpar when it comes to technical chops. Micro-detailing, instrument separation, imaging, and clarity are below average. The soundstage is intimate in all three dimensions, and music sounds congested and veiled when complex riffs come out to play. Thus, the D-Fi is for chilling and relaxing to music rather than critical listening.

The D-Fi is sub-bass focused, with moderate bass extension. Bass quantity is just north of neutral, depending on whether the bassiest or least bassy profile is activated. Having said that, the D-Fi is not a bona fide basshead IEM even with all switches flicked up. Bass is quite agile and textured on the bass-lite variations. On the flip side (no pun intended), once the bassiest configuration is in place, the bass becomes muddy and ponderous.

The lower midrange is neutral. This region is pretty transparent on the least bassy switch, though the bassier options add mid-bass bleed, which may encroach into the mids. The upper mids are just a tinge forwards, with a 9 dB pinna gain ensuring vocals are in front without being overly shouty.

Treble rolls off early in the D-Fi, even on the least bassy permutation. This is a far cry from the garden variety KZ steroid-infused treble, and treble-sensitive folk should be quite at home with this tuning choice. Sibilance is minimal, with a smooth higher end. This is a double-edged sword, as there is a lack of air, clarity, and sparkle, which may not be a treblehead’s cup of tea.


COMPARISONS

Comparisons were made against other budget DD types that are tunable. Planars, hybrids, and pure BA IEMs are omitted, as the different transducers have their own pros and cons.

The comparisons below are made with the D-Fi on the least bassy switch setting.





Simgot EA500


Graph of the Simgot EA500 on various nozzles. 8 kHz is a coupler peak.

The EA500 operates via two screw-on tuning nozzles instead of switches. With the black nozzle installed, the EA500 has a neutral bright lilt, whereas there's a warmer Harman-like tone on the red one.

The EA500 has a slightly thinner note weight and sound more metallic in timbre. The EA500 has more air and sparkle, with a greater treble extension on both tuning nozzles.

The EA500 boasts superior technicalities, with a wider soundstage, better imaging, micro-detailing, instrument separation, and micro-details.



TRI Star River


Graph of the TRI Star River on various nozzles. 8 kHz is a coupler peak.

The Star River also incorporates tuning switches. Like the D-Fi, these switches are somewhat duplicitous - out of four promised signatures, there are only two on independent graphs, with both sporting an old-school V-shaped profile. I also encountered QC defects on my Star River - one side’s switches were stuck, requiring considerable force just to toggle them.

The Star River is shoutier and more fatiguing, sounding quite unrefined in the upper midrange and treble. Timbre is also less natural, with a thinner note weight. The Star River has slightly better technical prowess, with improved soundstage, micro-detailing, clarity, instrument separation, and imaging. However, the bar is low, as other DD-type transducers easily beat the Star River in this department.


CONCLUSIONS

The D-Fi defies expectations of KZ tuning. No pun intended.



It is a different kettle of fish from KZ’s customary V-shaped beasts, sounding refined and neutral with a sub-bass boost. Indeed, the D-Fi would not be out-of-place if packaged in a Tanchjim or Moondrop box with a waifu gracing the front.

The D-Fi is non-fatiguing, smooth, and laid-back, with a natural timbre. Ergonomics, build, and accessories are acceptable for an IEM retailing at around USD$30.

Regrettably, the sixteen potential tuning permutations are more marketing than reality, with only a 4 dB difference in bass amongst these configurations. As such, you can probably save a few bucks to get the non-tunable variant of the D-Fi.

The D-Fi is glaringly lackluster in technicalities, and its tuning lies on the dark side of the equation - detail freaks best consider other options. Additionally, there is hiss with some sources.

KZ has markedly revamped its tuning philosophy in recent times, with tonally solid IEMs such as this, the Krila and Ling Long. Perhaps for its next release, the engineers could consider implementing a set with more audible differences with the tuning switches to bestow legitimate versatility. And now that the tonality is down, perhaps they can focus on getting good technical chops in.

All things considered, the D-Fi is cheap as chips and can claim a stellar price-to-performance ratio. It is a suitable IEM for those new to the hobby, though, for ChiFI collectors who already have more IEMs than ears, it might be wiser to save up for a more substantial upgrade down the line.

DISCLAIMER

I would like to thank Knowledge Zenith for providing this review unit.



NOTES:

The KZ D-Fi is an interesting release from the long-standing manufacturer of earphones and other portable audio devices. It is noteworthy for a few reasons of which two stand out. One is their implementation of tuning switches which is actually straightforward. The other is the overall tuning which is a pleasant surprise and a contrast to most past KZ parts.

There are two different versions of the D-Fi available, one with tuning switches and one without. Each has the identical 10mm dynamic driver with the tunable version driven through a Zobel Network circuit design. The tuning of the version void of switches corresponds to all switches down (Off) of the tunable version. Tech aside we all know that it is the sound that matters and here this “budget” KZ is a departure from the typical aggressive V-Shaped tuning of past offerings. The D-Fi is satisfyingly neutral with if anything a slight sub-bass boost.

The D-Fi is a very attractive iem with a solid all metal build. On the version with tuning switches, they are implemented as per many other earphones. Small dip switches with two distinct positions per switch. A tool to manipulate these switches is provided.

The D-fi is relatively easy to drive but the bass quality in particular and clarity to a lesser extent does benefit from being driven by capable amplification.

Overall, the I found the D-Fi pleasant to listen to with a nicely detailed bass and an organic sound. Not a technical champ, the D-fi excels when casual listening and just enjoying the music.

Read on the find out the details.

SPECS:

· Drivers: 10mm dual-magnet dynamic driver

 Impedance (Ohm): 23.5Ω (standard version), 29Ω – 48Ω (tuning switch version)

 Sensitivity (dB): 110

 Frequency Response (Hz): 7Hz – 45kHz

 Removable Cable: Y

 Cable: high-purity silver-plated cable

 Source Plug: 3.5 mm

 Cup/Shell Plug: 0.75 mm 2-pin



EQUIPMENT:

EIDA 9038SG3 (Stock Filter)

Xduoo MT-602

Shanling UA2

Tempotek Sonata E44

Ifi Hip-Dac

Topping a50s Amplifier

SMSL Sanskrit 10th MkII DAC

Tips: BGVP W07, Final Audio E

Cable: Stock 4.4mm Balanced Cable



BUILD, FIT & QUALITY

The KZ D-Fi is a nice looking iem with an all metal body that is of apparent good build quality. The haptics are very reassuring here and the D-fi has pleasing weight but not to an extent that will have a negative impact on comfort.

The included accessories are somewhat sparse. The D-Fi came with foam tips installed but a few sets of different tips were also included in the box. Nothing over the top but an improvement over many past KZ budget releases.

As for the included cable, it is the typical wire included with budget KZ earphones. Not inspiring and to be honest I prefer not to use it. It gets tangled easily and the haptics are not noteworthy.

Fit was excellent and I found that it was easy to achieve a snug position in my ears without fatigue, even after long listening sessions.

Still in the end it’s all about the sound quality. Read on.




SOUND:

BASS

Bass goes deep and is taught, fast and detailed. The first three tuning switches each raise the bass shelf by 3db individually. Even with the switch 1,2 & 3 engaged, the D-Fi cannot be considered a basshead iem. I found that bass quality did suffer somewhat when all three bass switches were engaged simultaneously. At most, I listened with two switches engaged or with none as per the out of box experience.

The bass was the first thing that stood out when first listening to the D-fi. It was taught, fast and musical. “Circumstance” by Wayman Tisdale sounded crisp with good control in the low end. “Intelligent Hoodlum” by Manix has very solid and dynamic bass. The D-Fi kept everything under control.

The acoustic bass on “No Worries” by the Robert Glasper trio was easy to discern and enjoy on this fantastic track that gets seriously busy.

I found the low end a pleasant surprise when I remembered my past experiences with past KZ’s in this price range. The bass of the D-Fi stands in great contrast to those KZ’s of not so long ago which more often than not favored quantity over quality. With the D-fi the tables have been turned. Here the bass does serve as a solid foundation to the rest of the frequency range while not drawing undue attention.



MIDRANGE

The midrange of the Knowledge Zenith D-Fi has good clarity. These are more of a macrodetail focus than microdetails. Lower mids have a natural presentation heard on “Tenderhearted Lover” by John Stoddart, with the upper mids bring more accentuated yet remaining clean with harshness. Female vocals do tend to sound more forward due to this upper midrange boost, yet again without sounding harsh or sibilant. Layering and separation are ok. On “No Worries” by Robert Glasper the individual instruments were distinct and I found it relatively easy to focus in on each separately.

On “Beautiful Lie” by Vic lavender, a track that many iem reduce to a wall of sound, the D-fi performed well even though not being class leading. It was able to keep each musical element in their place as opposed to combining them into a less than homogenous mess.

The midrange is quite pleasant and a more suited for casual listening as opposed critical listening. It is not offensive and can provide a very pleasant listening experience when not being overly critical.

The midrange has a surprisingly organic quality which honestly, I found surprising. This made it easy to manage long listening sessions. Timbre is also ok if not class leading and lends itself well to an overall satisfying musical experience. If I were to nitpick, in particular at its price, the D-fi may have been lacking a small measure of the organic playback I find so alluring.

TREBLE:

Treble is somewhat elevated and relatively well extended with ample air and sparkle. It mirrors the general nature of the midrange with macro over micro details but combined with a smooth delivery that at very rare times can have some minor peaks.

There is no harshness noted here and listening fatigue was not present either. Again, as in the midrange, the treble is suited for casual listening as opposed to razor focused critical listening. It’s will not offend with its smooth delivery and being articulate enough to maintain interest.



IMAGING & SOUNDSTAGE:

The KZ D-Fi offers up a moderate sized soundstage with good width and to a lesser extent depth and height. Imaging is also accurate and it is easy to discern the position of instruments. The D-fi also holds up well on more complex tracks.
The D-Fi is not class leading on any of these metrics but with its mix and balance of capabilities it does offer up a pleasant atmosphere.

CONCLUSION:

The KZ D-Fi is a pleasant surprise on a few levels. It offers a pleasant balanced sound and not the typical aggressive v-shaped tunings heard in many of KZ’s more budget offerings.
I found the D-fi to be very easy to listen to and admittedly really enjoyed my time with it. If this is the direction that KZ is moving to with respect to tuning, I am all for it.
The build quality combined with the switches, which do not get in the way, are a plus but the real star here is the sound quality.
At an asking price of under $30usd for the tunable version, I believe that KZ has a winner on their hands.