The Zaph ZDT3 build

[WmAx]

Chris, if you're making a box with this much (very dense) padding, how do you adjust the inside volume?

I.e. are you considering the walls of the rockwool to effectively be the inside of the cabinet (for the purposes of volume calculation), and therefore building a much bigger box, or do you keep the same box size and have a much smaller open volume inside?

I actually specified a rather minimal amount of the material. It has very little effect on volume, as it is still a porous fiber based material. It is actually regular insulation - just compressed to about 3-4x the density of regular/common insulation materials and set with a glue of some sort to hold shape/density. However, if you excessive amounts, like I do in my own projects, it will actually reduce the ability of the box to act as a spring air-mass system. I did not specify an excessive amount for application here. Just apply 2" on all walls, 4" directly behind the drivers, and 4" - 6" on the very bottom panel of a tall floorstander to prevent 1/2 and 1/4" wavelength problems associated with the relatively long column.

-Chris

 

[sploo]

Hi Chris,

Many thanks for the info.

I have actually used similar products before (for acoustic room treatment). I guess because of their relative solidity, I'd (wrongly) assumed they would have a significant effect on the internal box volume (from the point of view of the air spring).

At what point (i.e. "excessive amounts") do you have to start modifying the enclosure volume to achieve the desired air spring of an equivalent unpadded enclosure (and what do you consider excessive)? A sub-question would also be - how do you calculate this change?