Why Should Bass Traps be Mounted 2-4 Inches off the Wall?
One of the things that we recommend our customers do with their Bass Traps / Acoustical Panels is to mount them 2-4" off the wall. The absorption is 4 times higher at 500hz and below.
This happens because the sound goes through the panel, travels to the wall bounces back and passes through the panel again offering 2 opportunities for absorption. We can't take the credit for that great nugget of knowledge, it comes directly from Bob Hodas (the best in the biz).
Why should bass traps be mounted 2 to 4 inches off the wall?
Despite how the title reads, the right spacing is 2 to 4 inches off the wall, not 24. Mounting a bass trap that gap off the wall gives low frequencies two passes through the panel instead of one, which meaningfully increases absorption around 500 Hz and below.
Here's why the gap works: sound travels through the panel, hits the wall, bounces back, and passes through the panel a second time on the way out. That second pass is where the extra low-end absorption comes from. This comes from Bob Hodas, one of the most respected names in room acoustics.
Going wider than 4 inches mostly adds empty air rather than more usable absorption, so 2 to 4 inches captures the benefit without needing a bulky standoff.
Should bass traps be mounted flush or off the wall?
Off the wall, 2 to 4 inches, for better low-frequency performance. Flush mounting is fine for general absorption at higher frequencies.
Why does 2 to 4 inches help and not more?
Beyond that range you're mostly adding empty air, not more useful low-end absorption from the panel itself.
What do I mount the panel on to get that gap?
An off-wall standoff kit that spaces the panel's frame away from the wall behind the Z-clips.
Does this apply to every panel or just bass traps?
It's most noticeable on panels used as bass traps (typically 4 inch), since the gain shows up in the low-mid range.
See corner bass traps, or call (888) 923-5777 with mounting questions.