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[DPRG] Subwoofer vortex cannon

Subject: [DPRG] Subwoofer vortex cannon
From: swindle at compuserve.com swindle at compuserve.com
Date: Sun Aug 4 12:50:58 CDT 2013


Wow. Lots of planning and detail. Sounds like fun.

A couple things you've probably already thought of:

1) The pipe has to be non-stretchy. Even if you use a vacuum-cleaner hose
or a pool cleaner hose, it might stretch, and that may wipe out most of
your pressure changes. Those hoses work because they are under constant
pressure (or vacuum), and they change shape once. Yours would be breathing.
Corrugated pipe restricts airflow more than smooth pipe.

2) If the pipe is long, then much of your air flow will be just overcoming
the inertia of the air in the pipe, using up some of the woofer's energy.
Would it be better if you could be pumping the air one way instead of two
ways? Could you make a valve at the woofer end to replentish air?

3) Be careful that the woofer you're using doesn't have a back-pressure
relief port. I have some Altec Lansing woofers that will blow out candles,
which looks neat and scares people, but it's not really the woofer that
blows out the candles, but the blast of air coming from the relief port in
the center of the woofer. Such a port would circumvent (no pun intended)
your efforts.

4) If you discover that you need more power, then consider the fan woofers.
They are like helicopter rotors, able to move (or not move) large amounts
of air almost instantly. They are fans that are spinning and which have
blades whose pitch can be rapidly changed. Frightening, huh?

Have fun!
John Swindle

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