Is there one place in the room you can place a sound source that will stimulate all three axial modes simultaneously?
YES! [spoiler: it is a tri-corner where two walls meet the floor or ceiling]
Room modes ring
Everyone, it seems, has heard of room modes and knows they are not a good thing. But how bad are they really?
they have relatively long decay times BUT
stimulation requires approximately one full second AND
most transient musical material does not last near this long
Does this mean you should ignore them completely? Absolutely not. Take this opportunity to read the full article on this subject, or cut right to the proper positioning below.
Let’s get into the practice of avoiding “pumping” the modes so we are not limited in our listening material or playback level. How to accomplish this?
Take a nicely proportioned room of 16’x21’x10′ tall. We play it in the traditional direction and want to optimize the bass using stereo subwoofers, front-firing. Take 29% of each dimension and place the sub that distance from each boundary.
From the front wall, measure to the front baffle. From the side walls, measure to the center of the dust cover. From the floor, measure to the center of the dust cover. In this graphic, we have placed the subwoofers on top of ASC SubTraps, which are optimized to control room modes through bass absorption and vertical driver positioning.
We hope your have enjoyed this week’s tidbit. Next week: fine tuning your subwoofer and full-range speaker positioning to avoid self-cancellation or boost!