D.I.Y. Bass Traps- calling acoustic techs....

To deal with a 50 Hz bump you will need the trap to be VERY large in diameter. This is an absorbing kind of trap and to be effective needs to make it to the 1/4 wavelength, that is roughly 5.5 feet.

If you go to our resource page. you will find there is an article on bass traps by Ethan Winer which we supported. This is a good intro into types of traps and how they can be effectively used.

FWIW - large = minimum of 16 inch thickness for absorbers ...and probably all four corners treated extensively (floor to ceiling)

You could use resonators but they tend to ring - and in the end it may be better to have a hump and a better RT60 than no hump and a poor RT60.

The biggest problem in my room is a +5.5Hz bump at ~100Hz. To reduce it I'm going to try adding a set of the pipe wrap bass traps.

Jon Gale, who is usually credited with this DIY plan, wrote on one forum that there is a "supertrap" version. The biggest change is the addition of a second smaller fiberglass tube inside of the first one. While a little more complex to build they are supposed to be more efficient (more absorption in a smaller volume).

Can anyone offer details about the size of the second tube? Is there a specific ratio between diameters involved for optimum efficiency or tuning?

Did something similar with stacked 20" pipe insulation and rock wool. It's an expensive way to go and not very effective below 80Hz, no matter how it's stuffed. For 50Hz, you have to get real creative, like built-in, floor to ceiling membrane traps. 50Hz problems are not that typical and may be just a harmonic or resonance (pushing back) from an adjacent room.

Jockey...funny you mentioned resonance. I woke up this morning and had that same thought. The bar in the corner and the wood cabinet my gear is in are both resonating like a drum!! I am going to work on those units before I go crazy on giant barrels of rock wool and fiber glass.
Upon reflection it just does not make sense that I should be getting that bump anyway. Thanks for the input. Now I need some ideas on how to get my furniture under control since I will not be able to use a heavy pro shelf in that room due to a WAF situation.

To follow up, I emailed Jon Gale and he responded. He had discussed the "supertrap" idea with ASC and the final verdict was the level of complexity of the build is not worth the difference in results.

My original thought was that a more efficient trap in the same package might be useful to Blueskiespbd. Hopefully it didn't appear I was hijacking the thread.

Update: The bar has been removed and the DIY bass traps installed in the rear corners. Big, big improvement. Flat panels added and moved around with great effect to smoothing out the tweeters also accomplished. This is better than buying new components. That Rives test cd and my Radio Shack spl meter are getting a pretty good workout.