Discussion in 'Modifications and Tweaks' started by purr1n, Dec 6, 2016.
Here is my attempt to replicate the mod... if there is anything you see i have done wrong, could do better please let me know!! Thanks in advance.
I did swap out the one layer of foam for the folded over kept flush/slightly inserted into magnet hole and it helped with the bass. WowyWowsers these things sound excellent. Haven't wanted to listen with anything else lately!
Looks like Marv's KISS Mod to me @e.schell .
Messing around with the foam disk insertion, i know Marvey said not to push it in too far because it screws up the sound (mids disappear) but you get such a stupidly fun amount of sub bass it's addicting with EDM.
I've since found a happy medium with a sticky sorb block holding the foam in place, but I've replaced most of my sorb dampener with second skin damplifier pro because sorbothane is terribad in cold/dry weather. Still toying around with channel balance but otherwise things are going smoothly.
anyone else had a hd650 with spider and foam removed + dynamat that tried to add the foam crescent of the KISS mods and didnt like the results?
I do find that adding the crescent foam reduce the 100hz boost and make the bass tighter, but I feel some of the infamous veil came back...
^^^ Yes, me. I've tried re-adding all sorts of different damping behind the driver including various amounts of stock foam. I have a dynamat donut on the magnet and adhere damping material to the top of it. Certainly it reduces the bass to more tolerable levels but openness and microdynamics seem to take a hit. I find it a bit dull and unengaging. For my tastes, in the end I would rather deal with the extra bass.
I think this is a bit amp dependent. Valhalla 2 suffers more than Jotunheim on re-adding foam. Unfortunately Valhalla 2 also has a greater need of bringing the bass down a bit...
Did you try coin mod?
Hmmn.. is the grill off permanently or is it just to show how the mod installation went? If the grill is supposed to be on, does anyone have pics of the completed mod with grills on?
Put the grill back on.
I don't know about others but I always put the grill back on after pics. I remember solderdude measuring the differences between grill and no-grill in his Hd650 compilation google PDF if you were interested in a good read. (Post 4 for the forum for the link, pg40 in the pdf)
I liked it more with a small circle of foam cut to fit inside my dyna-donut so it's flush with the magnet than I did with a disk of foam hovering above the hole. You could try this if you haven't already.
Thanks, will give that a try!
I have a modded pair and a stock pair. I find that the 650 with no foam and no spider is too wild in the bass and I prefer the hd650 stock but I do find the stock hd650 overdamped making the sound a bit too dark .
so you added the spider back without ill effect?
Reflections from the spider and metal grills are secondary reflections and are probably desired?
the spider circle is not in line with the drier vent and is not far from the metal grills , about 5mm away from the grills. removing the spider to remove reflections seems pointless since if the spider would really creates undesirable reflections that would go back to the driver, the metal grills would also behave similarly.
I think that the original mod for hd650 (remove the foam and spider) seem to add air and clarity because the removal of the foam allow secondary reflections from the grills back to the driver. a bit like in room acoustic, first reflection are detrimental but secondary reflections are desirable! the biggest problem is that no foam adds too much at 100hz hence the KISS mod.
Foam over the hole vs foam over the entire magnet!
the KISS mod adds back the hd650 stock thickness of the foam over the hole via the folded layer of foam. the biggest difference is that the 650 stock has 2 layers of foam that covers the whole magnet. The Kiss mod reduce considerably the foam circumference and therefore reduce the absorption of the secondary reflections. I begin to think that the secondary reflections are desired in the hd650 and that its why removing as much as possible the back foam is best.
so, I think that keeping the 650 stock with the spider and the 2 layers of foam over the hole but trim as much as possible all around the magnet so that the foam would only cover the hole should work well and would leave the midbass FR just like the stock hd650 and make this mod even easier.
trimming the foam as much as possible also allow to apply dynamat on the magnet.
so to make this mod even simpler, i think one could get identical results:
trim the foam so just the hole is covered by the foam. (white marking)
apply dynamat (grey marking)
The problems I think you might run into are a) will there be enough dynamat on the magnet to damp it properly? and b) will trimming the foam mean that the foam sits too loose over the hole in the magnet?
Given that trimming the foam is arguably performing non-reversible mods anyway, you might be better off just removing the spider altogether. Having said that I personally prefer a single foam layer on top of a dynamat ring, and I don't have a spare 650 to experiment with other configurations.
Incidentally, if anyone wants dynamat for the KISS mod, I still have some spare lying around that I don't have any use for. If anyone wants some and is willing to put up with slow international shipping (no cost to you) chuck me a PM.
What did KISS stand for again? I'm having trouble remembering.
Keep it simple silly!
More like his sarcasm, but yeah
I tried to put this mod on top of the dynamat ring that I already had applied. I felt that it wouldn't be a good idea to remove the dynamat on the magnet because it glued like hell. I didn't have the rear foams anymore so I cut out a piece of the foam pad in the earcup (which I replaced with coin modded K240 foams). Any thoughts? Maybe too much dynamat? Bass still seems a bit bloated for my taste.
The front foam is pretty thin. Try doubling up if you haven't already (it looks like only 1 layer in the photo). More rear damping will reduce the bass response a bit and tighten it up.
I just did KISS Mod as well as quarter mod (coin mod).. I found that it is still a bit veiled. @Marvey did not find it is necessary because he is pairing with Jot if I understood correctly. I am using Meier Corda Concerto and it must be not as resolving as Jot so it did better for me with Coin Mod....
Edit: @Marvey Thank you so much for sharing KISS mod to community. I found that it is easy to follow and sound is definitely better after mod.
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