The sands of rare booming dunes emit low-frequency musiclike sounds while they are slumping or undergoing forced shearing. Such dunes have been known for more than 1500 years. The first quantitative recordings of the short-duration (≲1 s) forced emissions (obtained at Sand Mountain near Fallon, Nevada) reveal that the seismic spectrum is composed of sharp peaks between 50 and 80 Hz. The 50- to 80-Hz acoustic spectra resemble the seismic spectra and also display a lower-amplitude first-harmonic component (100--160 Hz). Approximately 0.1--1% of the shearing energy is converted to seismic emissions. Generation of acoustic energy is approximately 200 times less efficient. The available literature on booming dunes and results of a concurrent sedimentology investigation of Sand Mountain are summarized.