Why do speakers lose bass when elevated?

Question

They say when you elevate speakers with a sub and horn, the subs lose a lot of power. Why is that?

Answer 1

Thats not always a bad thing.   Putting speakers on risers can make them sound tighter and less boomy.

Answer 2

Bass in particular benefits from a corner (wall/wall/floor) or floor (wall/floor) location .. it tends to reflect the bass notes better and give a type of reinforcement.

Answer 3

The reason the sound you hear from the speaker changes when it is off the floor is due to the resonance of the floor. When a speaker is in use, the sound it produces resonates its enclosure and surroundings considerably, in this case the floor. When you move the floor away from the speaker by hanging it or picking it up, it looses that resonance.

The reason that this changes the low frequencies more noticeably is because of the wavelength of lower frequencies. Lower frequencies have much longer wavelengths than higher ones do. Tones tend to resonate best objects that are similar in size to their wavelengths. In your case, the low frequencies are vibrating your floor causing resonance. When you separate the two objects, the sound still vibrates the floor, but not nearly as much because it is more difficult for the energy to transfer into the floor without contact.

This phenomenon is actually the reason why windows sometimes crack when stereos are too loud. It would be impressively loud for a stereo to be able to put enough pressure on a window to crack it. Its actually very rare that this is the case. It is much more common that the window is the exact length of a wavelength being played at high volume. This would vibrate the window quite a bit, cracking it.

I hope this helps.