Editing Subwoofer (section)

===Matterhorn===
The Matterhorn is a subwoofer model completed in March 2007 by Danley Sound Labs in [[Gainesville, Georgia]] after a U.S. military request for a loudspeaker that could project infrasonic waves over a distance. The Matterhorn was designed to reproduce a continuous sine wave from 15 to 20&nbsp;Hz, and generate 94&nbsp;dB at a distance of {{convert|250|m|sp=us}}, and more than 140&nbsp;dB for music playback measured at the horn mouth.<ref name="TVTechnology" /> It can generate a constant 15&nbsp;Hz sine wave tone at 140&nbsp;dB for 24 hours a day, seven days a week with extremely low harmonic distortion. The subwoofer has a flat frequency response from 15 to 100&nbsp;Hz, and is down 3&nbsp;dB at 12&nbsp;Hz.<ref name=Matterhorn2007 /> It was built within an [[intermodal container]] {{convert|20|ft|sp=us}} long and {{convert|8|x|8|ft|sp=us}} square.<ref name="Matterhorn" /> The container doors swing open to reveal a [[tapped horn]] driven by 40 long-throw 15-inch (40&nbsp;cm) MTX speaker drivers each powered by its own 1000-watt amplifier.<ref name="MatterhornPDF" /><ref name=PhotosFromNSCA /> The manufacturer claims that 53 13-ply 18&nbsp;mm {{convert|4|x|8|ft|adj=on|sp=us}} sheets of plywood were used in its construction,<ref name="MatterhornPDF" /> though one of the fabricators wrote that double-thickness 26-ply sheets were used for convenience.{{Citation needed|date=June 2023}}

A [[diesel generator]] is housed within the enclosure to supply electricity when external power is unavailable.<ref name="Matterhorn" /> At the annual [[National Systems Contractors Association]] (NSCA) convention in March 2007, the Matterhorn was barred from making any loud demonstrations of its power because of concerns about damaging the building of the [[Orange County Convention Center]].<ref name="TVTechnology"/> Instead, using only a single 20 amp electrical circuit for safety, visitors were allowed to step inside the horn of the subwoofer for an "acoustic massage" as the fractionally powered Matterhorn reproduced low level 10–15&nbsp;Hz waves.{{Citation needed|date=June 2023}}