ZMF Bokeh Review: Just Can't Get Enough

In Corpus Christi, we have this pool of gear that I share among the local Schiit guys and few others. Between us, we have over a dozen ZMFs, Grados, and Audezes. It's sort of like take one, give one, and borrow it for months. The ZMF Atrium was very popular, being out of the my house for months. I heard that two guys at Schiit were borrowing it. I snagged it back, to the chagrin of one of the guys. I guess he missed the Atrium so much that he finally bought a pair from ZMF for himself!

I digress. Zach is at it again, this time with the latest TOTL $5500 wonder! Just kidding. This time around, Zach heard the pleas of the working class: can't we have ZMFs too! It's my understanding that the Bokeh will be priced affordably. Not only that, the Bokeh is easy to drive. I believe normal impedance is 80-ohms (I will measure later) and it barely takes a turn of the volume to get Bokeh to high volumes. We are taking Grado or ETA sensitivity here. No need for the "most powerful" transformer coupled single-ended triode amps capable of driving the most current hungry planars. (I hope you guys know I am being sarcastic because most of the type of amps only output 1-2W at most into 32-ohms).

Zach sent a bunch of sundry accessories to let me tweak the Bokeh to my liking: two meshes, the Bokeh Burst Mesh and Solid-Mesh; and three sets of pads, Protein, Suede, and Hybrid. I think Zach read my mind or knows what I like because the Bokeh was set up exactly to my preferences with the protein pads and bokeh mesh. I tried other combinations, but kept coming back to how Zach shipped the Bokeh in the box.



The look and feel of the Bokeh is very elegant, perhaps the most elegant of all ZMF headphones so far. The Bokeh really feels like something directly from Fostex. (What's the joke? tTat ZMF makes the best Japanese headphones - except he's not Japanese). The rodblocks are plastic instead of metal, but they don't feel cheap nor do they look designed by a Chinese outfit overly obsessed with SINAD without any design sense. The cable connectors are 1/8" TS jacks instead of the mini-XLRs. I assume this is to keep costs down. The inside of the pads are cavernous, so people with big ears won't have to worry about the tips of the ears being squeezed.

 

When I first put on the Bokeh, it was really hard for me to put my finger on the sound. After changing stuff up, DACs, amps, etc. to arrive at good sounding system, I finally figured it out:

Take a Audeze, give it dynamic driver sensibilities, tweak it so it's got a bit more body and is not so nasal, and voila! I guess this is variant of the ZMF house sound. With respect to technicalities, that is microdynamics and plankton, it's about Fostex TH900. Slam and articulation between Drop TH-X00 and Fostex TH900 level. I know the Fostex woodies come to mind, but the tuning is different from the TH600/900 and Drop TH versions. There's no lower treble sharpness like on the TH600/900. There's no midrange honk like the Drop TH-X00s or Verite Closed. To sum things up in a phrase: full bodied seductive sound.

The thing I did not realize until several hours listening is that there is no trademark ZMF woody coloration or reverb effect. There's a bit of woody, but it's toned down. The Bokeh plays it back pretty straight here. Internal reverb and resonances are damped perfectly. The Bokeh doesn't feel stuffed or overdamped to the point where dynamics are killed or headstage is collapsed. This is impressive.

I don't think I will be able to get through the full suite of measurements tonight. However, here is frequency response. The one measurement that will tell us almost everything, that is 80%, of what we need to know about any headphone. (Again, I'm being sarcastic. However, frequency response is important though).

ZMF Bokeh
Burst Mesh and Protein Pads
Frequency Response
DF Compensated*


ZMF Bokeh
Burst Mesh and Protein Pads
Frequency Response
1db/Octave Downward Slope Compensated (from above)


Associated gear pairing notes:

• Modi+ and Syn HP output (in a jiffy): Highs too splashy. Not good.
• Modi+ and Topping L50: Pretty good.
• Magni Unity w/ Unison DAC: Dang, pretty good. If you are on a budget, are an entry level audiophile, or have limited desk space, do this if you really love the Bokeh.
• Modius E (--xlr-cinemag-se-->) Magni Unity: Very good
• Modius E (--xlr-cinemag-se-->) Pietus Maximum: Now are are talking. Scales up a little bit. Although I get the sense we are reaching limits here. Will try from Mjolnir 3 or my unobtainium tube amps later.

* Long story, based on this: https://listener800.github.io/?shar...650BS_(Dilupus)&bass=0&tilt=-1&treble=0&ear=0
and this: https://forum.headphones.com/t/developing-a-new-headphone-reference-target/20094/31

Attachments below are the original measurements where I did not position and seat the L channel properly.

 

I went back and darkened the targets in the first graph. As an aside, note that Harmon 2015 was omitted (it's kind of somewhere in between 2013 and 2018). I added Audeze house sound as a rough target because Audezes have been around longer than Olive targets and a ton of people love the Audeze tuning.

LOL, you've been studying the CSDs!

We like to use CSDs to provide supplementary information. Many times it's to confirm that deep dips are disguised peaks. Other times, it's to verify if a deep dip is long lasting or temporary, that is result of complex sound wave interactions that occur inside the earpads, baffle, and ear. A temporary deep dip, where the dip exists in the frequency response* from the the first timeslice at t=0, but not a few slices later, in will not sound as severe as a permanent dip.

The probably explains why I hear the ZMF Bokeh as laid-back, not quite as much as Audezes. Also note lack of any sharp ridges or long lived ridges in the highs and super clean floor, which reflects lack of strong woody resonance play / cup reverb typical of ZMFs up until now.

ZMF Bokeh
L Ch
CSD Measurement


ZMF Bokeh
R Ch
CSD Measurement


Here is an example of a deep dip in the frequency response that stays as a dip in the CSD.

Audeze LCD-X


*Frequency response is basically an FFT of all timeslices from the beginning of the impulse response to the end of the FFT window.

 

FYI, I redid the L channel and posted updated results in second post.

Sorry @zach915m for borking this in the first place. I was tired last night and wanted to get the review started ASAP. I shouldn't have rushed. As you very well know, with comfortable squishy pads, it's very difficult to position and seat things on a coupler. I'm usually super anal retentive when it comes to measurements, something was was instilled into me in my first year engineering measurement lab at UCD. The labs were hilarious because we broke up into groups and measured stuff. Some groups sucked - couldn't get consistency / repeatability. It's all about paying attention to the smallest details. We had hardcore old school professors from LLNL and Los Alamos / Manhattan Project, the really old guys attested to the tales of the "blue light" accidents with plutonium cores. I'm sure @zerodeefex can attest.

 

Let me wrap up the measurements. Will send the package out as an SBAF loaner. @zach915m: OK with this?

 

ZMF Bokeh vs Atticus


Main differences: Atticus isn't a full bodied, but has a localized mid-bass bump (fun). Atticus also has the ZMF wood play thing going on. The wood play and mid-bass bump makes Atticus one by my favorite ZMFs.

ZMF Bokeh vs Eikon


Eikon is bolder in the lows. Even dark in highs but I suspect this has to do with the type of drivers and transient response. Slower and with articulation than Bokeh.

 

Currently at loss for words and this is why I haven't said much. It's not Biodyna, it's not the Be in the TOTL ZMF, not TPE. LCP isn't zippy, yet it's super articulate with great separation, while not being quite as sharp a the Biodyna. Felt it was kind of important to point this out. I guess one just needs to hear it.

 

Impedance is about 90-ohms and super stable. This is a nice spot. With its voltage sensitivity and high Z, should be easy for portable amps.

ZMF Bokeh
Impedance
Free Air


ZMF Bokeh
Impedance
On Head (GRN)

 

I don't think it would every be possible to totally eliminate the sharp treble of the TH900. Keep in mind that the Bokeh is tuned differently. The TH900 spiel is sub/low-bass monster with ultra-sharp cheese. The Bokeh is a full-bodied affair. The bass of the TH900 is cleaner, the Bokeh's bass fuzzier, but the LCP material has this articulation that overrides the fuzz.

Atrium is definitely takes the cake. Looking forward to the closed Atrium. That I expect to be something special, but we are jumping up a level with respect to price.