Sonic deception

Sonic deception refers to a deception tactic in the battlefield that involves the projection of sounds to produce noises. The recorded noises target the enemy's sound ranging set as well as the human ear. It is employed in various activities, which include vehicular movements and the construction of infrastructure and military facilities.
Tactic.
Sonic deception is defined as the generation, use, and distribution of sounds, which could include actual recordings and artificially generated noise that are blended to produce sonic experience on the battlefield. The effect could lead to the confusion or distraction of the enemy. As a deception strategy, it can also be used to mislead the target. 
The integration of sonic deception into larger battlefield tactics involves not only the access and use to recorded sounds and noises. These materials are used with actual equipment or personnel so that it is convincing to the enemy force. For instance, if the goal is to deceive the enemy into thinking that a sonic deception is an M1 tank platoon, an actual M1 tank must previously be seen driving around the area. It is assumed that the less effective visual observation is on the part of the target, the more effective the projection of the deception is. It is explained that the deception is more effective when employed "to confirm, in the mind of the enemy commander, the information which he already has received as a result of visual deception."
The deception must also be compatible with its environs. The sound of tanks, for instance, is not going to be believable in a dense swamp.
History.
In the age of Antiquity.
Examples of sonic deception during the ancient times included the Biblical story of Gideon's assault of the Midianites. The attack was carried out at night to hide his almost nonexistent force. He also ordered his soldiers to blow extra battle trumpets, each simulating one unit so that it sounded as if his army was heavily reinforced. The clash of sound and light sent the Midianites into a frenzy, hampering their capability to respond.
Modern period.
Sonic deception in modern warfare emerged out of the secret Project 17:3-1, a joint Army and Navy program tasked with researching and developing the potential military uses of sound. This initiative led to the creation of the Army Experimental Program during the Second World War. It was commanded by Lt. Col. Hilton Railey and was headquartered at Sandy Hook, New Jersey. Its initial experiments, which borrowed from the Nazi's use of sirens on civilian population, were aimed at terrorizing enemy combatants using sound. It later commissioned Bell Labs to produce and mix recordings of screaming bombs. These were recorded on three turntables and were used as part of a strategy to deceive the enemy into believing the existence of a phantom army.
The Army Experimental Station also recorded various noises that were used against specific enemies. For instance, the sound of barking dogs was employed against Japanese soldiers when it was learned that a Japanese superstition associates the sound with imminent death. Some of the earliest sonic deception strategies involved the use of radio deception to mislead Germany about invasion points in Europe. The elite Beach Jumpers was formed to carry out sonic deception operations at sea. For example, they effectively diverted the attention of the Germans away from the Allied true invasion point by creating sonic deception off Cape San Marco during Operation HUSKY.
In the European theater of the war, sonic deception was used in an elaborate ruse to fool the Germans. It involved the so-called Ghost Army, a campaign staged by the 23rd Headquarters Special Troops, an elite force that specialized in tactical deception. It employed inflatable tanks, rubber airplanes, and costumes to stage more than twenty battlefield deceptions in the forests of France. Another example involved the first part of Operation 11th Panzer Division, which used sonic and visual elements. The 23rd Headquarters Special Troops deployed three tank battalions at Grevenmacher and Wormeldingen while two dummy field artillery batteries were staged at Saarlautern. Sonic deception was employed in these cases to support the illusions that projected an omnipresent army. It included prerecorded soundtracks of armored and infantry units, which were then played using amplifiers and speakers that were so powerful they could be heard within 15 miles. 
The lack of noise is also considered a sonic deception tactic. This is demonstrated in the case of radio silence, which often denotes an impending attack. The strategy employs silences in areas where the enemy is expected to send troops so that activities (e.g. troop movements) can be carried out elsewhere. 