For a long time I was searching for the ultimate closed back headphone according to my listening preferences. After years of purchasing and auditioning different headphones, I wound up with a ZMF Blackwood. To date it is the only blind high end headphone purchase I have made, and I don't regret it even though it was risky.
The ZMF Blackwood is a heavily modded (by hand) Fostex T50RP (MK3 at this point in time). I own a stock T50RP MK3, and the difference is indeed significant. It is extremely impressive how fine tuned the Blackwood's treble is, but more on that below. The Blackwood was actually the first T50RP I ever listened to! And before this, I was accustomed to the Stax SR-007A and other top of the line headphones... so I am hard to impress.
I purchased my Blackwood in Q1 2018, so it is a newer model with the suspension headband design (ZMF headband) rather than the pilot pad. This is a better, more comfortable design that I can wear for hours with no soreness or discomfort afterwards. These headphones are on the heavier side, but you can never tell with a suspension headband and such soft pads. I have only used the stock cowhide leather earpads, the lambskin ones put your ears closer to the driver, but based on my experience simply holding the headphones closer to my ears, the difference seems insignificant (unlike a stock T50RP for which the difference is huge). My Blackwood also has Blackwood cups. The build quality is superb, the Blackwood is a looker and a showpiece. Makes most other headphones look and feel like toys.
A bit about myself: overall my favorite headphone I've heard to date is the Stax SR-009 though I've only auditioned this, followed closely by the SR-007 (both variants) and then the Audeze LCD-4. I prefer a transparent, mostly neutral yet musical sound signature generally speaking, but I can also enjoy a warmer sound. I am 24 years old, and using frequency sweep tests, I seem to be able to hear up to 19 KHz. I enjoy a wide variety of music, from different kinds of metal (melodeath, progressive, industrial), rock from the 70s, 80s, 90s, and early 2000s, classical, and some rap.
Other headphones I've owned when I first wrote this review: Stax SR-007A, Sennheiser HD 6XX, AKG K7xx, Beyerdynamic DT 880 250 Ohms, Audio Technica ATH-A900X, and some others I didn't use as much.
Get the seahorse case! It's excellent, really protects the headphone from dust and everything else.
My audio chain is as follows: Chord Mojo -> Schiit Lyr 3 (preferred with Raytheon VT-231 6SN7 tube) -> ZMF Blackwood. This is what is used for the review, although I mostly got the Blackwood for on the go use directly with the Mojo. I'll say it here: the Mojo drives it fairly well, volume isn't a problem. I don't even use more than 75% volume with the Mojo and the Blackwood!
The Lyr 3 makes a big difference however: it really improves dynamics, making it more lively. Bass extension and sub-bass impact is way better with the Lyr 3, treble is much cleaner, instrument separation improves as if an extra dimension is added. I'd say the Mojo alone drives the Blackwood to around 80% of its full potential, which is still really good.
My impressions below are with one bass port closed, my favorite way to listen to the Blackwood with the Lyr 3. Comparisons between different configurations are later in this review.
The Blackwood is a surprisingly phenomenal all-around headphone. No real weaknesses to my ears, and I don't say this often! It sounds linear overall, smooth and never harsh with a good amp, but very musical and euphoric with awesome dynamics and slam. The bass extends very deep, and combined with the impact with a powerful amplifier like the Schiit Lyr 3, you get bass performance that only a planar can deliver. Vocals are a bit forward with the Blackwood, the only thing in front of them is sub-bass slam. Great mix of detail without ruining poor recordings, transparency, slam, bass extension, treble clarity, imaging, rapid fast decay. I was not expecting performance this good out of a modded Fostex T50.
I am rather picky about headphone sound. A lot of headphones others love sound dull and/or unimpressive to me, and I can pick out problematic frequency ranges in almost all. So it is quite unique for a closed back planar to not have any complaints from me, but here we are.
Think of Audeze's sound signature, then remove distinct treble dips that cause some recession, fix the loose ends up top (in other words, fix Audeze's sound signature perhaps?) and you've got something close to the ZMF Blackwood's sound signature, which I suppose is the "ZMF house sound."
Yeah, this headphone has perhaps the best overall sound signature, frequency response, tuning of any I've heard. Which would apply to the ZMF Ori too since that's in the same boat. It's between this and the Stax SR-007 for me, and perhaps the SR-009 as well (I'd need to spend more time with it but now we have the SR-009S).
Let's look into this in a bit more detail.
Bass
Very deep bass extension with incredible detail and awesome impact. This headphone is so darn FUN with this impact and slam. I don't find the bass impact/slam overdone, but some may disagree. It doesn't obscure mid range detail so I'm fine with it, although the bass slam can be the most up front sound with this headphone; I've noticed this only in rap music with powerful and aggressive amps like the Schiit Lyr 3.
I also have the Sennheiser HD 6XX on hand, which is the best headphone I can compare it to I suppose.
ZMF Blackwood bass is at least three leagues above the HD 6XX, and has similar detail to my unmodded (and admittedly underpowered) SR-007A to my ears but with more impact and sub-bass body. It almost sounds like live percussion: percussion instruments are the most realistic, transparent sounds this headphone produces I think.
The bass performance is truly elite, and it transitions into the mid range excellently with no flaws to my ears. There is no evident mid bass hump to obscure the mids, like so many other closed back warmer headphones.
The cowhide leather pads are very thick.
Mids and Treble
The mids are lovely. They sound quite linear to my ears, yet musical the entire time. Both male and vocals tend to take a slight forward presence just compared to the rest of the midrange, and both male and female vocals are highly immersive. Transition to treble is seamless, and there is absolutely nothing in the treble that bothers me. No harshness, sibilance, not with all bass ports open or just one closed at least. This all changes drastically depending on how many bass ports you seal.
With one bass port sealed, the balance and overall response is so well balanced when used with a neutral amp. The Lyr 3 with a Raytheon VT-231 6SN7 tube provides so much bass slam, the most lively sub-bass I've heard of any headphone, but the bass doesn't bleed over and obscure the mids like basshead (V-shaped frequency response) headphones. The Blackwood does every genre justice, even classical! Seriously, after all my headphone experience, from the Audio Technica ATH-M30X all the way up to the Sennheiser Orpheus HE-1, I've never encountered another closed back headphone that can both deliver this quality and quantity of bass, and play a complex classical track while giving every instrument and row their own properly separated space. Mind blowing performance, while sounding accurate the entire time. Every instrument sounds accurate.
It's incredible how the Blackwood is never strident or harsh anywhere, when powered by the Lyr 3 and with one or none of the bass ports plugged. One of my favorite songs to test is Sledgehammer; Rihanna's voice sounds strident on most headphone setups including the HD 6XX, but not this one. Not only that but this is a very busy song and the Blackwood separates the instruments and sounds better than a lot of open back headphones.
The detail retrieval in the mids and treble is also good especially for a closed back headphone. The Blackwood doesn't even sound closed back... imaging is solid, sound stage doesn't extend outwards much but nor does it sound enclosed to me. It shows how incredible a job Zach does with the damping of the Blackwood! Truly impressive stuff here.
It's also incredible how fast and realistic the decay of this headphone is. I'd never expect this type of performance from a closed-back, non-electrostatic headphone.
Genres
What genres do the ZMF Blackwood excel at? I would say it excels at every genre that doesn't demand the biggest sound stage, namely large classical ensembles. So everything aside from that? Sounds about right to me. Remember, this is coming from a PICKY listener. This headphone is that good. It's capable of doing justice to a greater amount of genres than 99% of headphones I've listened to, and I've listened to tons. Zach from ZMF just found the ticket to a very ideal sound signature with his headphones.
Bass Port Impressions
The Blackwood has three bass ports on each cup, which you can plug with the many included rubber seals (it includes plenty of extras). I find that plugging one bass port CLEARLY results in the best overall sound when using a good and neutral amp. As a result I didn't spend as much time testing the other configurations since it was so clear cut to me.
All bass ports unsealed - The bassiest sound, but the mid bass starts to sound relatively loose and uncontrolled compared to the other configurations. More laid back sound, a bit less treble response. Best suited for strident/bright/harsh amps as this configuration will help to balance it out, might also be best if used with an amp/device that cannot sufficiently power the headphone. Also, for songs that have more sub-bass than mid-bass (rap in particular), some may prefer this configuration even with a well matched amp.
One bass port sealed - This leads to my listening impressions above, this is how I listen to the Blackwood most of the time. Excellent balance, bass tightens up compared to all ports opened although some sub-bass impact is lost (not noticeable the vast majority of the time, only really sub-bass heavy songs will make this noticeable, I've only noticed it in rap). I wouldn't call the Blackwood laid back or lush with one bass port sealed.
Two bass ports sealed - Detail retrieval becomes a bit more clear and it sounds more neutral, but it starts to sound artificial and harsh in the mids and treble, aka like most "neutral Hi-Fi headphones." A fatiguing listen, but one most of you are accustomed to as so many other high end headphones sound like this.
All bass ports sealed - I really didn't test this much since it sounded so artificial, harsh, and fake to me. Very fatiguing.
The ZMF Blackwood was a blind purchase, but what a purchase it was! It exceeds my expectations, mostly due to the treble performance for which I have no complaints. Unexpected from a T50 based headphone. It isn't as hard to drive as you might expect, it sounds great just with my Chord Mojo (though it's no more than 80% of what I get with the Lyr 3).
Update 06/08/18 - I am now in possession of a top of the line amp, the Pure BiPolar/Dynalo Mk2 from spritzer, with a Norne Solvine balanced cable and a Chord Hugo 2 DAC for good reference. The Hugo 2 alone drives the Blackwood as well as the Hugo 2 + the Lyr 3 (sounds the same either way), but the Blackwood did scale up a bit more with the new amp. It became a bit more transparent, bass impact and body and detail improved further as did instrument separation and imaging slightly. Quite the experience.