[Browntrout]

Hello everyone and a Merry Christmas, Just thought I'd share a cheap and very effective 'acoustic' treatment with you. I recently read about these  http://www.chimney-balloon.co.uk/
and thought it was a great idea so bought one. The room I listen in has a chimney and I had not concidered the effect this 'port' was having upon the sound of my system. After fitting one of these balloons up the chimney the bass has cleared up quite a bit with a much more defined character.
  I can certainly recomend these as a good way to tighten up the bottom end and help keep you warm during the winter months. Cheers, Ben.

[Bob in St. Louis]

Good idea, but a chimney would be a GREAT place to dispose of the rear wave of an infinite baffle rig.  aa

Sorry for the off topic, but I couldn't resist. 
Carry on gentleman.

Bob

[Ethan Winer]

Clever idea. I don't use the fireplace built into the rear wall of my living room, so I stuffed it with fluffy fiberglass and duct-taped cardboard over the opening. This makes a decent bass trap, which is useful because it's in the floor corner.

--Ethan