Directionality comes from how your ears interpret mainly two things: the loudness difference between the same sound in both ears, and the time difference between the same sound entering both ears. At low frequencies, where the distance between the ears is well below a half wavelength of the sound, the human auditory system uses primarily phase difference between sound received in both ears to tell direction. Key to understanding all of this is knowing the wavelength of the sound. Roughly, it is 1000 feet / frequency. Example: 50 Hz has a 20 foot wavelength. Below 200 Hz (5 foot wavelength), this no longer works effectively because the phase difference is too small to be detected, and below 80 Hz (12.5 foot wavelength) it doesn't work at all. This applies no matter if you're in a car, a room, or the Grand Canyon. See a simple explanation at http://en.wikipedia.org/wiki/Sound_localization A 15" subwoofer and a 4" subwoofer both playing a 50 Hz sound will produce exactly the same wavelength sound, just to clarify. A single high-frequency sound, say 1 kHz, will produce a complex interference pattern after bouncing off various objects on the path to the ears. This can cause both loudness and phase differences at the ears that are highly variable depending on exactly where the listener is. Try it sometime when you hear a high-pitched single frequency sound; move your head just a few inches and you will find the "source" of the sound coming from widely different directions. Ambulances using multiple frequencies reduces this (they will form more of an average) and adding white or other broad-spectrum noise will average sufficiently that the ears can correctly take the cue of loudness difference to locate the source. A long-throw speaker is designed that way because it is likely a smaller driver and needs to move a greater distance to move the same volume of air as a larger driver. It has nothing to do with where it rests when placed vertically or horizontally. It is difficult to make long-throw speakers linear because it is difficult to make a uniform magnetic field with sufficient strength over the full range of movement. The driver suspension (the "spring" force that keeps it centered) is far stronger than the weight of the cone. It is generally designed to have a certain spring force acting against the spring action of the air inside the enclosure. "Generally" because there are many options for designing drivers, enclosures, an