Custom Cans HD600/HD650 mod: measurements and impressions

So I tried removing the back foam today, and it turns out that the foam was actually sticky on the magnet. Therefore it was impossible to get it out without it ripping off, and a very tiny bit has got in the driver dome..

Would this be a problem?

 

I just saw that they offer a version specific for the Drop x HD6xx

https://jfunk.org/wpc/product/massd...l-plated-cnc-copper-mass-loading-mod-diy-kit/

Edit: oops. Already mentioned

 

Put it this way, it's never going to be beneficial.
Eventually the foam will take on a gloopy, sticky consistency and start to attract dust/detritus which may or may not cause micro-resonance/vibrations when playing music.

I have refurbed umpteen HD5*5/HD6** drivers all in various states of repair and by far the worst issue is when you get particles trapped inside or outside the speaker dome.

Your best bet is to shake the driver with the hole facing downwards until it comes out. Don't go poking things inside the hole as if you snag the tiny driver coil wires or puncture the thin polymer material it's game over!

Good luck!

 

What changes in the sound when you puncture a hole in the damping paper that I marked with red?

 

Immediate guess is that the low end may roll off alarmingly fast since there'll be less pressure behind the diaphragm to force excursion, and decays may be protracted likewise because there'll be less damping. I'm guessing a bit brighter tuning, a bit less macrodynamic swing, but it could also end up being somewhat more reactive to signal overall so maybe marginally higher transient speed?

I don't think the HD6-series has particularly rigid diaphragms so I wonder at whether the surface may deform more upon excursion, be less distinct in waves if the assembly was designed with that acoustic impedance at the rear? Wonder if that might haze up imaging ability. Hmm.

CAVEAT: this is all random theorising, I've not done this before nor played with nearly as many headphones as many others on here. Could well be talking out of the wrong end.

 

That’s what I thought as well, except a few days ago I saw this image: it looks like it’s damped twice with distance between the damping; one directly behind the diaphragm, after that some space, and then the 2nd dampers which is the ones we see normally on the backside

 

I've actually been playing around with a dynamic microphone lately and for whatever this noob's guesstimation is worth, I think it's all additive; the effects MAY not be as profound as in the event that the stuff visible from the rear were the only damping there, but I do think it could still result in similar effects, albeit to a lesser extent.

 

I bought a kit today to give it a go on my HD650s (also bought a cable from them for fun), will report back with impressions!

 

Arrived today, I've been listening for a few hours.



I ordered the copper version but then after some emails had ended up paying the difference for the nickel version instead, alas I received copper in the end. No big deal. My mistake for ordering the wrong thing to begin with. Regardless, pretty cool mod.

I really suck at describing sound and its impressions but I will try. I'm more of a subjective "does it sound good or does it suck" type of person... So I will begin by saying that the mod certainly sounds good and it doesn't suck. Because the low-end seems to be the focus with this thing, I fired up my favorite bass reference track which is Weedeater's Kira May. Immediately noticeably different from stock. The bass is thicker and more saturated. It doesn't envelop in an overwhelming way, I think there's a good balance. With some tweaking on the Loki, I prefer the low end cranked a quarter or two. The low end is much more satisfying than what I had come to know on these cans. I mostly use the HD650s for more mid-forward music, like the Beatles or Stones or various bluegrass bands, but the inclusion of this mod makes bass heavy, doomy stuff more enjoyable than it had been previously. Everything sounds smoother to me.

Another good reference for bass response is Bohren & Der Club of Gore's Sunset Mission record. I think these do okay here, certainly sounds good, though this kind of bass heavy stuff isn't the sort of music that goes well with the HD650's on their own, but it sounds balanced enough and very buttery with a slight boost in the bass. I am the rare Darth Beyer enthusiast where brain-rattling bass on tracks like Doom-Mantia or The Sun Has Turned to Black by Electric Wizard just can't be experienced in the same way on these cans. A heavy massive vibrating end-of-the-world sonic freakout is necessary for that stuff but can't ever be achieved on the HD650s. I think these bring the bass a little more forward but in a velvety sort of way.

Listening to things that I would normally use these headphones with like the Beatles White Album, with a little tweaking on the Loki, things like Long, Long, Long or even Neil Young's On the Beach grazes the ethereal. Live recordings are also awesome on the HD650s and the Dead or Yonder Mountain sound as crisp and tight as ever on here with just a smoother, more present low-end.

Overall digging this mod a lot, the copper rings will be living in these headphones for the foreseeable future.

Need to listen more...

 

Since I only listen on my left ear due to severe withdrawn eardrum in my right ear and tinnitus there (can’t stand any pressure on it), I decided to use the 2nd copper ring on top of the first one, keeping them together with some cut-to-fit ductape.

You’ll have to remove the grill in order for it to fit. It basically extends the bass more and gives a couple dB more emphasis in the whole range vs 1 copper ring, and makes the uppermids and highs smoother and less edgy.

 

It's easier than changing ZMF pads. Definitely gotta buy one for my HD650 now.

HD600 with perf suede ZMF pads:
I ended up liking just the copper over the bored foam, I felt the bored smoothed out too much the high end detail aka grittiness and I was raising the volume too far just to get it back. It also slightly changed the tone of voices.

The texture and resolution of the headphone now seems a little clearer, especially at lower volumes. Feels more dynamic now with actual bass reproduction. I'm interested to hear how it sounds now with the perf leather zmf pads.

 

Trying this on my new production HD600's and the bored foam is really nice, thanks for the recommendation earlier in the thread. Cleans up a bit of grittiness in the upper mids while tightening up the low end. Just got the mod today so i will listen to this for a while to get a reference point.

Might stick something like pantyhose or something to inside of the grills to keep dust/debris out of the driver.

Edit: Holy shit do i like this, if they weren’t already the HD600 are legitimate end game cans for me now.

 

Been doing some comparisons with the Clear og, focusing mainly on bass and subbass using some Recondite tracks and i have to say this mod brings them pretty close together. The Clear is a bit more detailed and goes a bit lower still but the difference is not huge. The main thing with the Clear is that it’s punchiness is fatiguing to my ears.

And if if i take the rest into account the 600 still comes out ahead, sure the Clear is less 3 blob but the 600 is quite good in that respect with my current amp. And then then the 600 wins by quite a bit on mids and treble.
Thinking of buying some ZMF pads to try… anyone use them with this mod?
Edit: am a dumb dumb and actually used the search function. Still not decided on what i want, suede or lambskin.

 

Suede sounds quite refined on the 600s, I've tried the perf leather on them and while the bass hits way better, it's also way brighter and a bit shrill at times. I liked the perf leather pads on the 650 instead. Its the only ZMF pad that wakes them up, otherwise I can't listen to them.

 

Yeah, i’m leaning towards the suede’s after reading around a bit. How you describe the perf leathers is opposite of what i’m looking for. From watching the ZMF video with the measurements it seems to reduce the upper mids a bit which seems ideal.

 

Fwiw I didn't like either ZmF pad on the HD650 but preferred the suede on the HD600. 600 is my once in a while headphone though.

 

Thanks! The 600 is my main headphone for the foreseeable future till my neck is healed. Also have a 650 kiss but i get along less with that one.

 

I've been sitting on the Custom Cans kit for a while now with a HD6XX hiding in storage. I couldn't bring myself to put the kit on the HD6XX, plus I stole the fresh ear pads and put them on my 2017 marbled HD600. I tried putting the weight over top of the stock HD600 foam, but they were slightly loose, and brought out a shrill sound in the upper mids/lower treble that I didn't like. I need to preserve these marbled HD600 in their stock form, so that one day they may look like EC Craig's beaten to death's doorstep HD600. I've been actively seeking a decent deal on a HD600, but most used models need new ear pads ($50 shipped for OEM, I don't like after market pads), and are priced almost as new. Finally I found a nice barely used, latest production set, without box for $200 shipped. A quick listen betweeen the modern stock (fresh pads) vs my old stock (ear pads are newish), and it's apparent the sound on the modern HD600 is slightly crisper in the mids, probably due to age of pads. In goes the Custom Cans mod the way it was designed to be installed and away we go, hmmmm this seems to have cleared up the mids and upper bass, but is bloated without any foam. I tried the hollow foam, the semi hollow 3 foam, and the solid foam (in order of bassiest to leanest). I like the hollow foam the most, still clean and clear with a nice touch of bass.

The nickel looks sexy!!



At the recent SoCal meet I finally got a chance to listen to a JAR600 vs my bone stock marbled HD600, on the Mjolnir 3. I've been wanting to do this comparison for quite a while. A quick listen under meet conditions, with fairly fresh pads on both, same stock HD650 DIY XLR cable, and it was apparent the JAR had a much cleaner, less up front midrange, than my stock. However I'm cheap, like good deals, and can't justify the cost of a JAR when I have the HD800 Super Dupont waiting in the wings, when I want high value, high performance (bought recently for $600 + $100 for new pads). The Custom Cans model is definitely headed in the JAR600v1 direction, but I think it falls slightly short, Those last few % cost $$$ in all areas of audio. I do like the fact the CC kit bottom end can easily be tuned with the different foams, really ingenious. Excellent high value mini upgrade!! sold out on the CC website, but I saw their ebay shop had them in stock recently

Quick and dirty measurement of the CC600 with the hollow foam, excellent channel matching



My stock HD600 taken immediately after

^Uh oh, slight imbalance, tried multiple times... oh well not too bad

Looks like slightly less distortion than the CC600

Anyway, I'll have to circle back and compare the two after a few months of wear to the pads, but so far the CC600 is excellent!!

 

@JK47 , great stuff! I suspect your measurement rig does better in the bass than mine. Would you mind doing comparative measurements of some of the different foam inserts to see the effect on bass extension? I got the impression that as well as changing the mid-bass hump and improving bass definition, the hollow & 3 foams improved bass extension as well.

 

The clamp on my rig is fairly tight, I'll take a picture of it next time I do some measurements within the next little while. The solid foam definitely dropped the bass hump down and probably the distortion in the bottom end as well