Intro:

Where to begin? What we have here is the work of the esteemed John Massaria who first rose to popularity with Kennerton mods which bewitched so many that they named a model after him with his modifications. I personally never heard these but that discussion lead me to take on these.

This time, he has done his same magic on the humbler Hifiman R7DX, a Drop(ex Massdrop) collaboration using not one of their planar drivers but a 50mm driver with something they called "topology diaphragm"

From their own description:
"The “Topology Diaphragm” or “Topology Driver” refers to the diaphragm with a special Nano particle coating applied to its surface. The distribution of the coating has distinct geometric patterns. By varying the surface pattern, compound used, the thickness or geometric pattern sound wave formation can be manipulated to achieve the desired audio effect and control."

How this works without JM's mods I personally don't know but the headphone itself debuted at $99 on sale and $149 normally so it definately fits in the budget or mid-fi categories.

So onto the review.

Build Quality:

Build quality wise, there is no difference from stock except some more weight in the cups due to the extensive mods. The cups are a matte plastic of good feeling quality. The headband design is the one we've seen many times with the Drop/Hifiman collaborations including the HE-4XX, HE-5XX, and HE-X4: a pleather non-replaceable headband with spring steel inside and light cushioning. The gimbals are metal with a round plastic cover with metal sliders. They feel well built although some have had issues so take that as you will and Google away.

The Setup:
I have no idea what the stock R7DX sounds like having never owned them. I have plenty of other headphones both open and closed though.

Source chain is Lossless FLAC/Spotify high quality mode -> Schiit Modi 3 -> Drop THX One (unless specified to be another)
The Drop THX AAA One is a single ended version of the lauded and highly transparent THX 789 amp. I love all sorts of music, some of it very disparate.

The 2 cans I chose to compare to are the AKG K371, for its Harman curve hugging tuning, and the Fostex TH-X00 Ebony for its bass performance.

Now the important stuff...

Sound:
First impressions were excellent. Bass was deep and impactful but tight while highs were nice and sparkly. Mids were very clear and clean as well.

For scoring 0/10 is free airplane headphones and 10/10 is the best I’ve heard in a category.

Highs: clean, sparkly, but not too rough. This is definitely not HD650 highs but also not Beyer peaky as well, just right IMHO. For those who are treble sensitive, it may be an issue, but it’s just right for me. High hats come in sparkly, vocals have just the right amount of extension. My own opinion is that “resolution” in highs many times comes from more treble extension in the mid to upper highs so at first listen they sound less resolving than brighter cans but like the HD650, the technicalities are there. They are not summit level but they are definitely above most mid-fi cans I’ve heard. I would give them 7/10 thanks to the combination of good tuning and very good technicality.

Mids: The heart of music is right here. With the highs sparkly but not too much and the bass extended but not too bloated, the mids shine through. Acoustic music and slow-medium speed music is where you can really hear mids very well with not too much going on. Combine the highs with the mids here and you have a pretty good combo in terms of resolution and technicalities. If I EQ down the highs of my HD800s, they do seem better still but of course, we are talking about the better performing (and pricier) ring radiator. I’ve heard endgame and higher end cans in passing but don’t own any and I honestly don’t hear a huge difference between those and less expensive headphones so take that as you will. I would grade these 6/10 as well as they don’t seem to do much wrong but don’t stand out either.

Bass: In a word, excellent. Great extension but also clean. Now JM has stated there are 2 versions of his mods, one “neutral” and one “bass”, these are the bass ones which line up more with my own taste. Now, these cans aren’t the last word in basshead quantity but that’s I doubt that’s what these were tuned for. They seem to extend down more than my TH-X00 Ebony Fostex headphones with less “flab” or distortion. However, these R7’s also has slightly less quantity in the mid-bass than the Fostex making the R7s sound a bit less full. The R7 has more neutral bass profile if that makes sense. I really, really like these. 8/10.


Imaging/Soundstage: For a closed can: excellent! A good way to get good soundstage is space for your ears and these are pretty big. They are among the best closed cans for soundstaging in opinion. Imaging is one of those things that seem to be subjective but the combination of good tonality and good soundstage make the imaging very good as well. I would say is soundstage is 7/10 and imaging 6.5/10.

Comparisons: We all know closed cans just don’t have the selection in the head-fi world that open cans do. This situation has gotten better but there always seems to be way more selection of open cans. That said, I will compare to the 2 I like best in my collection leaving out a few others I also have.

AKG K371 aka the Harman king. Needs no introduction here. Where the K371 follows the Harman target curve very very well, these are a bit different. Pull down the K371’s treble sizzle (which gets a bit choppy) and extend and tighten the bass and you have these which for me is near perfect in terms of tonality. If you switch from the K371 right to these, all of a sudden, the K371 sounds a bit leaner in the high mid/low treble area and brighter with similar bass but not quite as much. Soundstage is smaller also on the K371. I do prefer these cans but of course the K371 is a pretty damn good cheap closed can that does many things well.

Drop Fostex TH-X00 Ebony. Also needs not much introduction here. These are the famous 50mm Foster biocellulose driver with about 1 tesla of magnetic strength (compared 1.5 for their higher end TH-900). They are famous for their bass. Of the 4 cup materials these can come in (Mahogany, Purpleheart, Ebony, Teak), the Ebony’s 2nd most neutral with a tiny bit more zing and bass than the Teaks, the way I like it. All 4 headphones sound more alike than different. Now compared to these modded R7s, the Ebonys have much less soundstage. The Fostex also seem to have a tiny bit more bass but is also looser; extension is comparable. The looser/more distortion-y X00 makes them more a bass-head can for sure. By no means though are the R7’s lack in bass!
Amps: For the majority of listening, I use my super neutral THX amp but JM did tell me he preferred them with tubes and class A amps. To that effect, I tried my 2 other amps, the class A biased Schiit Asgard 3 and my G1217 Project Polaris, which uses JFETs at the inputs to cause 2nd order distortion, like a tube but with class AB output making this sound like a hybrid.

The differences were in line with what I was expecting, the Asgard 3 wasn’t a huge difference but in vocal music, classical, and anything more organic, there was maybe a smidge more warmth. Now with the Polaris and its distortion profile, there was a bigger difference. Again, more acoustic or organic type music had a slight more natural timbre to it while taking the edge off harder music or electronic music, if you want that. I honestly preferred these cans with my neutral THX amp with hard and electronic music but I do tend to have a bias towards more sterile amps by and large.

Conclusion:

You should be asleep by now. But if you aren’t, thanks for reading!

So the summary for those who don’t want to read my blob of text:

Pros:

• Excellent tuning, slightly flatter than Harman
• Very good resolution and technicalities
• Works with any type of music

Cons:

• Won’t be bassy enough for bassheads
• Limited availability due to JM’s hand speed
• Not the last word in performance

For closed cans, these may be my favorite right now. Now, value is harder to quantify, because I have no idea how JM will price these as going forward. If I assume $300, which is about 2x or 3x the price of the stock R7 depending on sales, I’d say these are a bargain and you need to grab one now. There’s a chance the stock R7 sounds just as good, I wouldn’t know, but judging the work JM has put into these, I would really doubt that.

For the price of a mid-fi can, you get a nice taste of something more. If you were to say you are stopping here and not buying any more, I can see that. The value proposition is very, very high here. You owe yourself a listen.

So message the man now or find a listing!