Should box linings be included in volume calculations?

Brisso57 · 20th December 2007, 08:09 AM

What is the general consensus? If the calculated box volume comes out (say) at 30 litres, should the builder build a 30 litre box and then insert lining ... OR should the box volume be fudged a bit to allow some extra, to give a NET volume of 30 litres after lining?

The question is not relevant to stuffed designs (TL's), but to boxes that are largely air.

If an allowance is to be made, is there a "rule-of-thumb"?

Thanks

Doug

jnb · 20th December 2007, 12:57 PM

Adding a fair amount of stuffing to a box increases the effective volume. Once the stuffing is compacted, the volume decreases.

I usually consider the net effect of a typical amount of stuffing to be zero change.

Cal Weldon · 20th December 2007, 02:27 PM

Quote:

Originally posted by Brisso57
is there a "rule-of-thumb"?

Quote:

Originally posted by jnb
I usually consider the net effect of a typical amount of stuffing to be zero change.

Iain McNeill · 21st December 2007, 07:47 AM

I think the question was regarding lining as opposed to stuffing, wasn't it?.

I have lined cabinets with cork & fiberboard to damp resonance and always felt that this should be accounted for in volume calculations as opposed to the fluffy stuffing which as jnb says actually increases effective volume.

Brisso57:
Can you be a bit more specific? Are you talking stuffing or lining? and what materials?

Brisso57 · 21st December 2007, 07:53 AM

Quote:

Originally posted by Iain McNeill

Brisso57:
Can you be a bit more specific? Are you talking stuffing or lining? and what materials?

How would you treat either case?

(I was really referring to lining to damp internal reflections.)

Thanx

Doug

Iain McNeill · 21st December 2007, 08:00 AM

Lining subtracts from internal volume.

Stuffing is net zero.

Really what counts is the acoustic impedance. If you can blow through it then it's stuffing.

20th December 2007, 08:09 AM	#1
Brisso57 diyAudio Member Join Date: Sep 2005 Location: the leafy west of Brisbane	Should box linings be included in volume calculations? What is the general consensus? If the calculated box volume comes out (say) at 30 litres, should the builder build a 30 litre box and then insert lining ... OR should the box volume be fudged a bit to allow some extra, to give a NET volume of 30 litres after lining? The question is not relevant to stuffed designs (TL's), but to boxes that are largely air. If an allowance is to be made, is there a "rule-of-thumb"? Thanks Doug __________________ A speaker-builder's parable: "That burned down, fell over, then sank into the swamp. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest castle of all."

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20th December 2007, 12:57 PM	#2
jnb diyAudio Member Join Date: Dec 2006	Adding a fair amount of stuffing to a box increases the effective volume. Once the stuffing is compacted, the volume decreases. I usually consider the net effect of a typical amount of stuffing to be zero change.

21st December 2007, 07:47 AM	#4
Iain McNeill diyAudio Moderator Join Date: Oct 2007 Location: Santa Cruz, California	I think the question was regarding lining as opposed to stuffing, wasn't it?. I have lined cabinets with cork & fiberboard to damp resonance and always felt that this should be accounted for in volume calculations as opposed to the fluffy stuffing which as jnb says actually increases effective volume. Brisso57: Can you be a bit more specific? Are you talking stuffing or lining? and what materials?

21st December 2007, 08:00 AM	#6
Iain McNeill diyAudio Moderator Join Date: Oct 2007 Location: Santa Cruz, California	Lining subtracts from internal volume. Stuffing is net zero. Really what counts is the acoustic impedance. If you can blow through it then it's stuffing.

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