Allright, NoXter and I had a
finetuning session last weekend with 2x MS1K, 1x MS1 and 1x Ulti as probands. I'll sum results up here, first the well known items
- thick felt on driver mesh - less treble sibilants
- partial closing of drill holes - adds warmth, reduces treble
- thick felt on top of distancer - less upper mids
- different caps (stock, small woody, big woody, no cap at all) - nothing
- perforated plastic disk on top of distancer - sh#t
We finally ended up with a
"3 drill holes, no felt on mesh, felt on distancer" configuration.
What we also found out is that felt isn't like felt. My good stuff was spent, so I bought new felt which turned out to have much less sonic impact. Meh...

Pics from caps trials:

