tube traps didn't help

For slap echo, try hanging a quilt, tapestry something absorbent around the room in the offending spots. The slap echo isn't always in the corners...it's more parallel walls that's the issue or ceilings and hard floors.

I have some of the ASC wall panels that do a lot for slap echo at about $50 each...

Don't overlook the value of book cases and books on the sidewalls - looks natural, as opposed to audiophile stuff, costs a lot less, and can be very good at diffusion if placed so that they minimize the side wall reflections from the speakers. Ditto rear wall.

Slap echo can easly be controlled with decorative carpets,Home Depot would be one source; be careful not to over do it.
There is a power cord that will take care of your bass problems,see [Which cables go with what] in this section.

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.

Gbmcleod - What are the dimensions and characterists of your listening room that have required such seemingly extreme correction? If I had 33-50 tube traps in my room there wouldn't be room for anything else. Please lend some insight into what problems you faced and how you were able to correct them.