On 3/30/2016 9:47 AM, John McCoy wrote:
OFWW wrote in
:

On Tue, 29 Mar 2016 21:48:19 -0400, krw wrote:

On Tue, 29 Mar 2016 14:12:26 -0500, Leon lcb11211@swbelldotnet
wrote:

The air volume does not change in a sealed speaker either. The
pressure does change but not the volume.

The volume of air obviously changes as the volume increases. ;-) The
quantity of air is constant, the pressure is changing, so the volume
must change (inversely). Remember, the speaker cone is moving.

Yet if there is no vent the volume of air does not change, only the
pressure changes. So the sound is dampened in that the speaker is not
free to fully travel, unless it is a metal coned speaker. I believe
that is what Leon was referring to.

Eh? You guys are trying to re-write the laws of physics here.
Boyle's gas law applies, p1v1 = p2v2, just as krw said.

This is not complicated - assume there is a speaker in a
sealed box. The speaker cone moves as it's being driven with
the audio signal. As the cone moves outward, the volume
inside the box increases, and the pressure decreases. As
it moves inwards, the volume in the box decreases and the
pressure increases.

Nope, in a sealed speaker the same amount of air is in the enclosure
regardless if the speaker cone is moving in or out. What you are
confusing is displacement. The measurable area, not air volume, inside
the speaker changes but not the volume of air. Air easily compressed
and decompresses, that does not decrease the volume of air.




As noted (several times) whether these changes are significant
depends on the size of the box relative to the speaker.

John