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Re: Background thumps in recording

Subject: Re: Background thumps in recording
From: "Keith Smith" keithahsmith
Date: Tue Nov 6, 2012 9:32 am ((PST))
Hi David,

Points taken, (and I'm not clinging to the artillery theory). I grew up
about 20 mi away from the birthplace of the Avro Arrow. Lots of 'booming'
going on in those days. Sometimes we could see the source (always from aft
of the beam), most often not.

I was looking to RAAF Edinburgh (north of Adelaide) as a source of capable
aircraft. Murray Sunset is roughly the same distance from there as from the
sea.

I played with Raven some more last night and exported a set 8 slices. I
hope they are useful to the discussion. If not, please make suggestions as
I'm trying learn whatever I can from this.

http://www.samplesmith.com/NatRec/120923_01_054104PheenysTrackCampsiteMurra=
ySunset0604-0605.wav-Slices.pdf

I can't see that 'pre-boom' you mentioned. Would you mind locating it?
There is a small LF 'disturbance' at 19s, but I have to crank my sub to
jungle music levels to hear it -could just be a breeze.

This *is* a lovely recording. I've got to get out of the city...
I'd be much inclined to leave the 'booms' in. I don't think they hurt
anything.
k


On Tue, Nov 6, 2012 at 6:35 AM, Avocet <> wrote:

> > Ah, me thinks RAAF Edinburgh 150+mi W is a far more likely
> > candidate.
>
> Keith,
>
> Artillery and shells at supersonic speeds produce sonic booms but at
> much lower energy levels than supersonic aircraft. Tou will never hear
> a boom directly in front of a plane because it will hit you first. :-)
> The boom trails out at an angle as a cone shaped pressure wave and
> quite a lot of the engine power goes into that perssure cone and it
> can travel many miles.
>
> Aircraft are not supposed to fly supersonic over UK land, so they
> practice over the sea. We get jets, probably from Wales, on a route
> between Exmoor and Dartmoor and they are just subsonic. You don't hear
> them coming, but when at low altitude, the sound level is very high. I
> haven't managed to record one yet.
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
>
>
> ------------------------------------
>
> "While a picture is worth a thousand words, a
> sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
>
> Yahoo! Groups Links
>
>
>
>









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