อันแรก LRAD Weapon long lange acoustic device  อาวุธนี้จะปล่อยคลื่นเสียงความถี่สูงไปยังศัตรูทำให้ศัตรูแก้วหูแตก แล้วเห็นเค้าว่ากันว่ารุ่นใหม่ๆนั้น สามารถปล่อยคลื่นไปกระแทกหัวใจทำให้หัวใจหยุดเต้นได้

According to the manufacturers specifications, the equipment weighs 45 pounds (20 kg) and can emit sound in a 30° beam (only at high frequency, 2.5 kHz) from a device 33 inches (83 cm) in diameter. At maximum volume, it can emit a warning tone that is 146 dBSPL (1,000 W/m²) at 1 metre, a level that is capable of permanently damaging hearing, and higher than the normal human threshold of pain (120 – 140 dB). The maximum usable design range extends to 300 metres. At 300 metres, the warning tone (measured) is less than 90 dB. The warning tone is a high-pitched shrill tone similar to that of a smoke detector.

There appears to be some disagreement over these specifications, as some have reported measurements that differ from the manufacturers specifications, and show reduced output with a less directive beam.

Its instructive to note that any loudspeaker of equal size will generate a beam of the same directivity as LRAD. The parameter "ka", which is the wave number multiplied by the speaker radius, is often used to characterize sound source directivity. For this source, ka=19 at 2.5kHz, and according to the LRAD data sheet, the beam angle of about 30 degrees total - precisely what is predicted for a regular loudspeaker ^[1]. Contrary to some beliefs, the device does not use ultrasound, nor is it a phased array; it uses an array of conventional acoustic tweeters, the same as those used in many professional audio applications, all driven together in parallel.^{[citation needed]}

Carl Gruenler, (former) vice president of military and government operations for American Technology Corp. (and who now runs a company making a competing device), says that being within 100 yards (90 m) of the device is extremely painful, but its use should be limited to 300 yards (270 m) to be effectively used. He concedes that the device is powerful enough to cause permanent auditory damage, but that it is only meant to be used for a few seconds at a time.

Countermeasures may include the use of passive hearing protection (earplugs, headsets), which may bring the sound down to ineffective levels. In addition, sound could be reflected from a solid surface, and redirected back to the originator.

Small spherical "point-source" acoustic devices follow the known inverse square law, which predicts the loss of 6db per doubling of distance from the source. Large speakers (or large arrays), such as these mentioned above or those commonly used in concert halls, etc., produce less loss with distance in the nearfield, typically 3-4db per doubling of distance from the source. The larger the speaker, and the higher the frequency, the longer the effective nearfield is (see Beranek). Devices like this generally have nearfields of only a few meters.