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After reading through the basic modification again, I've realized how close mine is to the latest document from BMF. Essentially, the only difference is,
- - I have craft foam in place instead of the acoustic foam. I do have acoustic foam and I've used it before, though.
- - I have plastix on my baffles and not newplast. I just received some newplast in the mail last week, though. Yippee!
- - I'm using fiberglass insulation instead of cotton balls at the moment.
I'm assuming that the documented use of Rite-Aid cotton was the use of the cotton pads instead of the cotton balls? From the instruction, it appears to indicated they are pressed against the insides of the cup - which would almost indicate that they are the cotton pads.
Yes, the Rite Aid Natural Absorbent Cotton Pads I use are cut to ~2.5x6x7 cm (uncompressed) and fill the cups from top to bottom and touching all 4 sides of the cups. I've tried pulled cotton balls layered to the same dimensions but I could never match the SQ of the cotton pads. That's not to suggest, however, that you or others cannot match or beat cotton pads with pulled cotton balls, rock wool, fiberglass, other felt, microfiber cloth, etc.
Is the craft foam you use closed cell or open cell?
I don't remember: did I send you some Acoustipack Lite to try?
BTW, I have tried fiberglass in place of cotton and in combination with cotton that, together, measure the same overall dimensions of my cotton pads. The results were similar but I have consistently achieved the best SQ and measurements with cotton pads. That said, I've had good results from reducing the thickness of the cotton pads by 5 mm and adding a sub-layer of 5 to 10 mm fiberglass to the cotton pads that measured ~ 2x6x7 cm.
FWIW and IME: Some configurations I've built have required extra "fluff" cotton teased and placed around the outside perimeter of the cotton pads filling all the gaps.
Small changes in cotton thickness and fluff work well for me when tweaking the bass:treble --> more cotton = more treble extension/detail/air and less bass; less cotton = less treble and more bass.
Closing the cup vents completely or, for some of my mod configurations, making a 2x3 mm bass port in one vent slot = better controlled bass to prevent bass bloat. There is still very good quality/quantity sub-bass extension.
Closing the baffle port = more bass.
Sealing wire and jack entry points into the cups = more bass that sounds tighter, to me.
Stiffened craft felt and/or Transpore tape of various sizes on the back of the drivers = tighter bass and more extended treble response.
Shure 840 pads work better for me than stock pads with my configs.
With all these mod components, I find that the key to achieving the best SQ is finding the right combination that produces a euphonic interaction.
As always, YMMV.
