This requires a powerful amplifier, a very large bass driver or several smaller onesand a lot of diaphragm displacement. Some experimental fixed-installation subwoofer horns have been constructed using brick and concrete to produce a very long horn that allows a very deep sub-bass extension.
Archived from the original on August 21, February The individual speaker cabinets are more compact and lighter than full-range speakers, and that is often an important consideration — especially in small home studios and for location-recording rigs.
A second method of rear delay array combines end-fire topology with polarity reversal, using two subwoofers positioned front to back, the drivers spaced one-quarter wavelength apart, the rear enclosure inverted in polarity and delayed by a few milliseconds for maximum cancellation on stage of the target frequency.
In September , Raymon Dones, of El Cerrito, California, received the first patent for a subwoofer specifically designed to augment omni-directionally the low frequency range of modern stereo systems US patent The THX organisation recommends crossing over at 85Hz, and I've found that to be a good starting point in most cases.
For instance, some floor standing tower speakers include a subwoofer driver in the lower portion of the same cabinet. From about to the s, the "lowest frequency in practical use" in recordings, broadcasting and music playback was Hz.