HD650 KISS mod

Discussion in 'Modifications and Tweaks' started by purr1n, Dec 6, 2016.

  1. purr1n

    purr1n Desire for betterer is endless.

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    I'll start with a fresh pair and take measurements again. Taking a few days off work before heading overseas for a week.
     
  2. gurubhai

    gurubhai Friend

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    No need to worry, the Arctic Cotton actually improves the low level resolution and openness.
    I have been doing these mods for about a decade with my planars and I can understand the worries about the ill effects of overdamping but I think I have struck a good balance here. Just give it a try and I can assure you that you would be pleasantly surprised.
    The mod is actually simpler than the stupid simple mod. Just make sure that you do the prerequisite coin and dynamat mods too.
     
  3. Yeskey

    Yeskey Friend

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    About that email... As it turns out, they're going to send me a pair for free. So your results may vary! (Thanks Sennheiser!)

    EDIT:
    I actually have some arctic cotton blends on back order from Jellyrollshop, but they're currently experiencing shortages. I'll try to get measurements of those as a sub to foam disks when they finally arrive.
     
    Last edited: Dec 8, 2016
  4. gixxerwimp

    gixxerwimp Professional tricycle rider

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    My rear foam had 2 layers. I trimmed 1 layer to fit inside my Dynamat donut and tacked it down flush with the magnet. Mid bass is reduced compared to having the foam hovering above the magnet and bass is tighter overall.
     
  5. MikeD

    MikeD Acquaintance

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    Yeah - that was a fairly reductive reading of the mod on my part.

    I would say though that the removal/addition of the rear foam was by far the easiest discernible audible difference to the 650 of all the mods I tried. Mass loading and dynamating I've found hard to distinguish from stock (I've no stock 650 to hand to A/B them). A while ago I rigged the 2 foams to small bits of tape so I could, with a grill-less 650, ping them off and reattach them whilst listening. It's quite a distinction. My feeling after messing about with it for a bit and then not using the 650 for a few weeks and then messing about with them again was thus:
    The 650 with 2 foam rings sounds slightly over-damped. It's super smooth.
    The 650 with no foam sounds a bit wilder, looser, more exciting but there's bloom in the mid-bass.
    I feel like there's an argument, according to sensibility, for either. Personally, I landed on reattaching my spider with 1 foam in it. It's mundane solution.

    I did, on first impression, feel this new mod was circling back to stock. I also felt that there's good reasons to do so.
    I think it's important, for a mod to succeed - especially in a community, that we're all clear on what it is & where's it headed. I would say, as @zonto expressed, that there's a return to some of the stock elements here. Most strongly in the return of the rear foam - which, in my experience, had the most profound effect on the overall sound.

    First impressions aside - I'm interested to see the mid-bass moving below stock. I'm looking forward to more listening impressions from across the community as people complete the mod.
     
    Last edited: Dec 9, 2016
  6. James Whiting

    James Whiting Facebook Friend

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    Agreed there was definetly more midbass after removing the rearfoam and spider but the overall sound improved noticeably! Covering the paper ports also seemed to effect that as well...although I found two ports covered gave me the best compromise between added mid bass and a livelier transient response and sense of dynamics. Damplifier Pro tightened everything up and improved the detail, but may have in fact slightly enhanced the midbass issue. But leaving all four ports open made things sound less involving and less dynamic.

    Felt around the backframe smoothed everything and slightly lessened the midbass response. But at this point it really wasn't possible to remember exactly how it was stock. I just much preferred what I was hearing! I listened to them without the grille cover and overall preferred that sound. It did seem however, to be just a bit off in the lower midrange, but midbass was noticeably reduced.

    I wasn't really happy with leaving the back off so I just made new grilles and did some foam diffraction absortption at the edges since it was something Hands mentioned might improve clarity and detail. It does...but just very slightly! I kept tinkering with different thickness of foam, including the cutouts from the nickel mod I did over the hole. And just in case anyone wonders...you can purchase any stock foam pads of pieces directly from Sennheiser. I started with the quarter mod...but am much happier with the nickel mod! The cutout foam was tacked down to the damplifier pro rings around the magnets with dyamat butyl . I settled on that for awhile...until someone on the General HD650 appreciation thread here suggested 1/2 foam doughnuts placed on the back. Lifesaver- looking foam lozenges. I cut down some foam paint brushes. I think he used some type of filter foam. Close enough based on material I had on hand. My homemade grille squishes this down and I put a bit of extra butyl rubber from my dynamatt extreme around the magnet edges to keep it all in place.

    That substantially helped as was suggested it would.

    Still not convinced it is absolutely right...but bass is a touch more extended and hint more detailed than it previously has been and the midbass is much closer to being correct on the majority of what I listen too. No appreciable change in the rest of the tonal balance. Upper mids and highs are perhaps a bit smoother! Big thing is no change in dynamics and sense of speed or staging, which placing foam over the hole seems to create in varying degrees depending on how thick or dense that foam is.

    But I am still open to suggestions!
     
  7. gixxerwimp

    gixxerwimp Professional tricycle rider

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    So much for "keep it simple" ;)
     
  8. James Whiting

    James Whiting Facebook Friend

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    Lol....yup I suppose that's true!
     
  9. thegunner100

    thegunner100 Hentai Master Chief

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    Gotta find some of my creatology foam left over from the Anax 2.0 mod days to do this mod on my HD650s while my HD800s are out on loan. Would definitely like to get rid of a couple of dB of midbass, as it's not needed on an amp like the Sonett 2 at all.
     
  10. gixxerwimp

    gixxerwimp Professional tricycle rider

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    @thegunner100 I think you'll find the mid bass is reduced even without the Creatology foam. The Dynamat and putting some rear foam back over the hole in the magnet are responsible for the bulk of the changes. I have no foam on mine and hear the same effects.
     
  11. thegunner100

    thegunner100 Hentai Master Chief

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    I lent my sheet of dynamat out, so I can't do the mods. I had the dynamat on the magnet before but found it to increase bass levels by too much.

    Edit: I've got double sided tape, so I'll try taping a layer of rear foam back on.
     
    Last edited: Dec 10, 2016
  12. thegunner100

    thegunner100 Hentai Master Chief

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    I left the grills off so that I can quickly peel off the foam for A/Bing. There does subjectively seem to be slightly less bass with a layer of foam in place.

    650.jpg
     
  13. purr1n

    purr1n Desire for betterer is endless.

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    The Creatology foam is unnecessary. It was applied to the back of the Xtreme for cosmetics and to make it easier to cut. The foam acts as a built in gunk cleaner on scissors used to cut.

    Again, the point of this was simplicity. I've done variations of many of the approaches on three pairs of HD650 keeping one stock for comparison.
    1. In terms of technicalities such as focus, clarity, microdetail, the Dynamat Xtreme does the most.
    2. In terms of bass, the reuse of the foam disks.
    3. All the other shit that didn't do jack or only had very minimal or debatable results were not done.

    The quarter mod was not done because I am using Jotunheim. I'd consider the quarter, or actually a dime mod for less neutral, or more laid back amps like Vali 2, EC, DNA, Woo, Cavalli, etc.

    I am open to suggestions on making the mod easier. For example, if anyone can provide a more elegant solution to the discs, I'm all for it.

    I consider augments to this mod such as cutting eight extra pieces, cutting complex shapes, lining the back completely with foam, blocking holes, using other complex layers of foam on the front, or any other shit not within the spirit of this mod... Well not in the spirit of this mod. There is already another thread on various random techniques, most of them not vetted, for HD650 mods.

    The point is not increase mod neurosis. The point is a quick and dirty mod for a more neutral more resolving HD650. I already f**k with shit too much and at some point I want to listen to music.
     
    Last edited: Dec 10, 2016
  14. thegunner100

    thegunner100 Hentai Master Chief

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    Does the crescent shape make a difference compared to just sticking 1 or 2 layers of the rear foam back using double sided tape or dynamat?
     
  15. purr1n

    purr1n Desire for betterer is endless.

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    As long as two layers of the original disc material is flush on the magnet with a small volume of it shoved into the hole 1/2 a mm or so, it should be fine.
     
  16. thegunner100

    thegunner100 Hentai Master Chief

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    @WhimsicalStranger just sent me a pic of the back of his hd580s. They seem to have a golden ring in the center of the magnet. Interesting...

    [​IMG]
     
  17. Colgin

    Colgin Friend

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    I can give you Dynamat when I see you on Monday.
     
  18. thegunner100

    thegunner100 Hentai Master Chief

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    Nah, don't worry about it. The hd800s are taking over as the primary headphones, otherwise I'll be using my speakers.
     
  19. k1arg

    k1arg Facebook Friend

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    My old (circa 2002/3) HD600 have the same goldish ring. I wonder if it is specific to models, or an age thing.
     
  20. Dino

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    Does your's have the black driver/baffle as well? (I am wondering if the magnet change could have occurred at the same time.)
     

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