Preface: I was a bowl user, and I was just converted to flats by the following trick.
You do that (with [red packaging] 3M Scotch or similar, but not [green packaging] 3M "write-on" Magic Tape nor electrical tape; I promise it won't leave behind any glue residue or take away foam if you remove the tape thereafter):
The flats have that they warmen the sound from bringing your ear and the driver closer together; but with tape a new significant level of quality is attained.
I'm rediscovering my Magnums v4 right now, and I'm in love! (haven't tried it on the HP 1000 but I'm pretty sure I'll love just as much already) The bass is more visceral and feels deeper, the sound is fuller (actually it feels like a whole new layer of texture and sound in the bass has been added), maybe even more detailed.. and...
Warning: Spoiler! (Click to show)
...in my opinion, the sound is way better (balanced, more palpable bass) like this. I mean... my story: I've swapped Grado pads for one year (HD414, bowls±tape, flats, upgraded flats, and combinations / reverses / quarter mods), and, pretty much, I think that I'm done with it, and that I found what I've been looking for all this time! (Grado nirvana of course)
I urge all of you that owns both a Grado headphone and TTVJ flats to try putting tape around its side, covering all the spongier, darker shade of black surface.
This mod should work for all Grados, except GS-(i) and PS-1000.
My open back Grado (now a bit more closed in nature) sounds a lot more like my closed back (not so closed / not sealing at all) Kotori 201 (read Creative Live Aurvana!, Denon AH-D1000 and 1001 in silver), and have gotten just as good for "enveloping me" in lush sound, thanks to that tape, making up for a sound-retaining capsule around my ears.
Comfort on flats (taped or not) is definitely lesser than on bowls (in conjunction with Sennheiser PX100/Koss KSC75 pads) for me. I'm working on accustoming my ears to these new pads.
Two previous failed attempt at augmenting the bass of my Grado through soft modding:(it looks bad for the eyes) (Click to show)
It might have improved the low end a bit but at the cost of much of the openness and of an added and a pretty annoying echo / artifact in the highs that I couldn't tolerate living with (so I quickly undone my mod).
And secondly; really, covering the open backs of your Grado with a film of "Glad press'n'seal" reduces bass and it doesn't add anything in return. So you're not missing anything if you don't try this in your life.
Don't be afraid to raise the volume, your Grados aren't near as harsh anymore.
Edited by devouringone3 - 11/23/12 at 8:35pm