[Boatanchors] Fw: acoustic resonance dimensions 1-3/4" (not 13/4")

[Henry Mei'l's]

hope this my last mail on this bit ;0)

Henry, Cph.

----- Original Message ----- 
From: Henry Mei'l's 
To: boatanchors at mailman.qth.net 
Sent: Wednesday, September 15, 2010 9:44 PM
Subject: acoustic resonance dimensions


1st construction in the Hints & Kinks article
calls for a 1"o.d x 13/4" brass tube closed off at one end by a movable stopper-operates by resonating at the desired frequency.

2nd construction uses a closed wooden or cardboard tube 8"H X 4"inner diam., spaced 3/8" above the cone of a 3" speaker, mounted in a cotton packed cylinder, 3"H x 5"o.d / 4"i.d. which in turn is joined to the resonance tube by angle brackets that provide a 3/8" air gap - operates by absorbing all but the desired frequency.