Nondirectional & Inaudible Bass: What Frequencies?

There are two issues about this. One is directionality, such as hearing a distinct sound coming from a source, vs perceived energy source. Thus GS has a point about the distance between the ears (except it should be 1/8 of a wavelength and your head can't move for that to really be true). My own listening says we lose directionality at a fairly high level, perhaps as high as 100 to 150 Hz, but we lose energy source perception somewhere between 40 and 60 Hz. Now there are many things that change these subjectively perceived values. For example, distortion in the subwoofer will translate into harmonics at higher frequencies, thus we may perceive directionality of a subwoofer that is crossed over at 60 Hz.

Room and placement of a subwoofer absolutely have an effect on this. There are multiple ways the room plays a significant role, from reinforcing bass frequencies (thus reducing total distortion) to positions at certain (say 1/4 wavelength) places that can create nulls and quickly give us clues as to where something is (at least generally).

One thing that makes a huge difference is multiple subs (as has been stated). This allows a flatter frequency response through the room, less work for each sub (thus less distortion), and two sources that make picking out where the sound is coming from very difficult.

Hope that helps.

Sean: Please keep in mind the differences between directionality and perceived source of energy. They are distinctly different, but often confused. It does seem by your comments (left hand speaker since that's where most of the bass comes from in an orchestra) that you did experience directionality as opposed to energy source. Therefore, I would suggest that there is something other than pure bass coming from the REL. Either distortion or harmonics at much higher frequencies than 27Hz. Having heard some of the larger RELs I am surprised, but not knowing the model, it could be one of the smaller ones and could be the cause for having this occur. You really have me very curious about this, because in theory it should not exist--but we all know that "in theory" is just that--and often does happen. Could I pursuade you to use a test disc, or better sweep tones and turn off your main speakers and find out what the actual response of your sub is. I'll bet you are getting information out of it much higher than you expected.