The Tube Traps are very helpful in taming room acoustic problems. I know; I've had 30 of them since 1988, when Stereophile first reviewed them.
HOWEVER, you can NOT simply place them and forget them. You must tune them carefully, by moving them along the side wall (if that's where you are using them). Try moving them 1/8 inch at a time, with the reflective side facing into the side wall, and them rotating the seam TOWARDS the speaker.
For a more detailed setup of them, go to Peter Moncrieff's classic article on Tube Traps. Here's the website: http://home.wanadoo.nl/thingman/trapart4_u.htm
This is an EXCELLENT article on how to optimize the Tube Traps. I used it to great effect when I had WATTS (the first 3 generations of them).
You can also buy some RealTraps, which I recently purchased. They are as effective (in the bass especially) as Tube Traps. Their website is: www.realtraps.com. They are MUCH less expensive than tube traps and work quite well at ceiling/floor junctures, as well as placed in corners. I was quite surprised at how much they cleared up the bass range; I put the Tube Traps in the same positions, and they're about equal in their effectiveness. HOWEVER, the tube traps have the advantage of absorbing AND reflecting, while the RealTraps, which work as well, don't allow for tweaking. The good thing about the RealTraps is that they come with a 30-day money back guarantee, so if they don't work well (unlikely), you can request a refund. I can tell you that a few people at TAS are using them, and I'm loaning a couple of mine to the Sea Cliff gang (although, they could clearly ask for their own!).
Finally, the Tube Traps, once you place them along a wall, MUST be rotated in tiny, tiny, TINY increments. Forge about 1/2 inch rotation: I'm talking about a 1/100" rotation. Trust me, it changes the sound in quite tiny increments. I think, as HP said in a past issue, that people don't use them right at all. They turn them 2" at a time: WAY too much. You'll have to experiment with them. It's the difference between good and excellent when you rotate the columns.