a box fill question

[mattmillme]

Hello, so I know box fill can help in some instances. On this web page Re: Fibre packing in sub enclosure why? it mentions and shows that as box size rises the fill gains decline. My question is; does the box size alone make the difference, or box size per woofer make the difference?

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[Louisiana_CRX 5,000+ posts]

Ive seen people use packing peanuts in sub boxes...Im not sure what they do

 

[mattmillme]

No one can answer this? C'mon guys...

 

[Jepalan]

Your question is too general. Are you talking about a sealed or ported enclosure? Are you talking about an enclosure where two subs share the airspace or where each sub has its own sealed chamber?

Fiber-fill is most commonly used in sealed applications where the box is slightly too small, or very close to manufacturer's recommended size. By adding fill, the resonant "bump" in frequency response can be flattened slightly, and the low-end roll-off can be extended slightly. It is the same effect as if a slightly larger box volume was used with the same driver. BUT, the effect diminishes if the box is already much larger than the recommended optimal box size for the sub. i.e. beyond a certain point adding more fill no longer has an audible or measurable impact.

The general principal of how fiber-fill works doesn't change if one, two, or more subs are used. If you have a dual sub enclosure that is slightly too small (based on modeling of the enclosure using the subs' T-S parameters), then adding fill can improve things. If the box is already too big for the drivers, then it won't help.