Ah....so you /want/ the echoes, but you don't want secondary sounds
interfering with picking up the echoes.
Big tuning fork? Let it ring for 100ms and then stop the vibration.
The sound travels 34m in that 100ms, so your dead zone is about 100 ft.
You can probe 100ft with a rod though.
Oh....what about a "launch box"? Get a 100ft of conduit bent into a
coil and connect that to the pipe being tested. Make it long enough
that the secondary noises from your emission source are over before the
first real reflection comes back.
-Adam
On 4/2/2020 3:52 PM, ch...@wbmfg.com wrote:
Acoustical TDR for characterizing conduits. Best to know what it
looks like before you try to blow something through it.
*From:* Adam Moffett
*Sent:* Thursday, April 2, 2020 1:44 PM
*To:* af@af.afmug.com
*Subject:* Re: [AFMUG] OT Project update
What's this for anyway?
Big sharp noise through a pipe is what I believe you said you
wanted.....but what is the purpose?
I suppose a gunshot sounds sharp in human terms, but it's really
rapidly expanding gasses being released. In hindsight it makes sense
that there would be an initial burst followed by diminishing secondary
noises. If that's an issue, then aren't echoes in the pipe an issue
too? I don't see how you would avoid the echoes.
-Adam
On 4/2/2020 3:37 PM, ch...@wbmfg.com wrote:
Walther handgun will not fire power hammer loads. Does not seem to
strike the rim at all.
But a 1908 Savage rifle will.
Seems gunshots are not a sharp impulse. Just a burst of noise I have
discovered. No where near a perfect impulse.
So having fun and probably scaring people driving up the highway but
on a quest for a high quality shock wave/sound impulse.
Recording engineers use balloons and clappers.
I have a high power speaker driver coming. Going to see what happens
when I get close to blowing it out with a capacitor discharge.
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