On Mon, Jun 20, 2011 at 04:41:46PM -0500, Charles Henry wrote:
> On Fri, Jun 17, 2011 at 12:48 PM, Fons Adriaensen <fons@email-addr-hiddenwrote:
>
> > For a real single sound source the direction of the
> > vector V(t) is that towards the source, and P(t) and
> > V(t) in any given point are closely related. They are
> > of course measured in different units (Pascal, and
> > meters/second resp.), one is a scalar and the other
> > a vector, but they are proportional.
>
>
> This doesn't matter to the rest of your analysis/description, but I'd offer
> a correction to this paragraph.
>
> V(x,t) is proportional to the spatial gradient of P(x,t).
>
> Note that this means pressure and velocity waves are 90 degrees out of sync
> with each other.
No, this is wrong. The gradient is 90 degrees out of
phase w.r.t. pressure, and rises by 6 dB/oct w.r.t.
pressure.
The velocity vector is the time integral of the
gradient, and consequently it is in phase with
pressure, and the P/V ratio is independent of
frequency (assuming far field).
Ciao,
-- FA _______________________________________________ Linux-audio-user mailing list Linux-audio-user@email-addr-hidden http://lists.linuxaudio.org/listinfo/linux-audio-userReceived on Tue Jun 21 04:15:03 2011
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