The tube traps DO work, but they need to be placed in the correct places, with the orientation of the seams correctly positioned, and that doesn't happen in an hour's time or so.
It has been said that the best place to locate tube traps are in the corners behind the listener, directly behind the listener's head, first and second reflection points of the speakers, and then behind and between the speakers. If you use two each in those locations, that's 18 tube traps. However, if they're 4 feet tall (the originals were 3' tall, which was when I bought them, back in 1987), then one should be a good start. It's also recommended that you get super 16s (ugh, the cost nowadays!), to handle the lowest frequencies your speaker produces, although ASC will suggest you get at least 1 super 16 anyway! (I have two). You can also use the RealTraps for this, though. I have 4 of them, and they work just as well -- IF you only need absorption. They don't 'do' the diffusing thing, so they are perhaps best placed across the corners behind the listening chair (if you have corners there, that is). They work immensely well, and they're only $159.00. Check 'em out at www.realtraps.com (No, I have no affiliation with 'em; I just want to see people get the best room treatment (for absorption) for the least amount of money. Given that I have 33 Tube Traps (I used to have 50!), I'm a walking advertisement for the company, but I went looking for something cheaper and when TAS mentioned them (the RealTraps), I found 'em - 10 miles away from me. Besides, they're returnable within 30 days if they don't work for you (and they're in excellent shape!).
But back to the Tube Traps. I've placed mine, and then moved them up and down the wall an inch at a time and that's how you place them. Never mind thinking ,"Well, this is exactly the point where it reflects in the mirror..." That AIN'T gonna get it. You gonna have to move them gently in one direction, and then, just to be sure,the other direction. Just make sure you mark exactly where they were each time. Put a penny on the floor dead in the center of the tube trap so that if, after moving them 2" the other way,you find the first way was better, you can jut put the tube trap so that the center of it is near the penny.