I saw some shelf-lining materials today while browsing for better meshes for the grill mod at the hardware store, and I thought... well, why not?
So I attempted to do the rest of the mods and see if the shelving would make any improvement.
Luckily, Hifiman let me keep my old Focus Pads, so I had 2 pairs, and I sacrificed one pair for the purpose of the mod.
My impressions are as follow:
Bass: there is... more there. I think this quantity is as a result of the ear pads seal mod and the regrilling mod (steps 3-4) more so than of the other 2 steps. Just to be clear, I did the regrilling mod (step 4) before doing anything else, and doing step 3 was simple enough, so I tested steps 3 and 4 first to be clear. Now... I think there is a marked improvement in bass decay and tautness after doing... step 1. But anyhow, bass improvement is real after doing all 4 steps. Dang if I had never heard better bass. This good a bass should be illegal.
Midrange: after steps 1 and 2, midrange becomes thinner and faster, but also a lot more transparent. I think this is because step 2 adds more air for better venting, and step 1 absorbs excess decay and reverb, so the end result is a fast and clean midrange. I think by removing the filter cloth in step 2, there is a slight but audible reduction of lower midrange warmth. Adding more air by enlarging the holes in the ear pads also slightly boosted upper midrange (6K?) from what I can hear, so that adds more to the thinness.
Treble: airy, and much less effortless as a result of step 4. Step 1 helps with decay and is basically that last 5% that's necessary for the HE-560 to sound pretty much on par with a Stax. I've just heard the SR-009 very recently, so at least from memory, I think the HE-560 is very close to it.
Soundstage: step 4 causes the soundstage to become much more 3D, much better positional information, and also much more expansive, immersive. If you're just after soundstaging, I think step 4 alone will do it.
So... verdict? I think step 4 did most of the grunt work. The other steps are just there to squeeze the last 5% out. As noted, I think the midrange got thinner as a result of step 2. It sounded more "Stax-like", but I didn't quite like it, so I decided to use the stock ear pads but still with the shelf-liner from step 1 (so basically adding shelf-liner and leaving it at that). Somehow, it still absorbs a good amount of decay, and the filtering cloth plus lack of bigger holes in the ear pads allow for a thicker, fuller, more rounded midrange with more lower mid grunge. And yet the bass and treble are still excellent.
Congrats, Jerg! I finally get to hear all of the improvements. I decided to scale back a bit and essentially "reverted" step 2, but for what it's worth, I think the improvements from step 1 and 4 are audible, and very appreciable. Can't wait to compare my HE-560 to the Stax SR-009 again in the near future! And I'm thinking it'll be a close battle.
