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You know about sidewall reflections…

…because you are a loyal Acoustic Tip of the Week subscriber.

You know that the near reflection widens the sound stage, and the cross reflection smears imaging. But did you know that TubeTraps played an important role in the development of the concept of controlling both reflections with one device? If you didn’t, you will after this!

A Free-Standing Corner Bass Trap?

Years ago, an excellent high end audio dealer was also a TubeTrap dealer. I said one day “Gary, how do you sell so many TubeTraps?”

He said, “Promise you won’t get mad when I tell you it is not the way you recommend?”

I said, “Of course. We all know TubeTraps go in the corners, but go ahead.” (what is he thinking? blasphemy!)

And Gary says, “check this out.”

I saw immediately what was going on: the TubeTrap near the right wall absorbs the cross reflection from the left speaker, and the early reflection from the right speaker is smoothly diffused. Imaging is locked in place while the ambience is wide and bright. Genius!

Gary continues: “Is it much easier and quicker to get people’s attention by bringing stereo imaging to life by doing almost nothing. Once they love the imaging, introduce them to tightening up the bass and there we are: another dedicated TubeTrapper.”

I said: “thank you, Gary, for a wonderful lesson.”

TubeTrap Sizes for Imaging

• 9″ diameter (optimal image control)
• 11″ diameter (excellent image control, improved upper bass absorption)
• 13″ diameter (excellent image control, excellent bass absorption)
• 16″ diameter (good image control, superior bass & sub bass absorption)

TubeTrap Height Options

For best image control, you want your TubeTrap to extend a little taller than your tweeter.

• 3′ units are 36.5″ tall, you may want to stack two
• 4′ units are 48.5″ tall, working well for many floorstanding loudspeakers

Where to Put the TubeTraps

How do you know exactly where to place the TubeTrap for best effect? Well, first off, point the chrome button, indicating the center of the reflective side, toward the wall. Then use the flashlight trick!

Optical Alignment

Set up flashlights so they mimic the sound path from speakers to listening chair. Place a mirror on the wall that is large enough to catch both beams. Where the beams intersect is where the image control zone is located. If the flashlights are on the floor, the beams and the crossing location become visible.