A news briefing detailed how American troops would take over the Iraqis’ FM stations and broadcast a silent signal underneath the audible programming:
The clandestine station programming consisted of  patriotic and religious music and intentionally vague, confusing and  contradictory military orders and information to the Iraqi soldiers in the Kuwaiti Theater of Command (KTO). The size and power of enemy forces was always intentionally exaggerated. Surrender was encouraged. According to statements made by captured and deserting Iraqi  soldiers, however, the most devastating and demoralizing programming was  the first known military use of the new, high tech, type of subliminal messages referred to as Ultra-High-Frequency ‘Silent Sounds’ or ‘Silent Subliminals’. (Newsweek, July 30, 1990, Page 61) Although completely silent to the human ear, the negative voice messages placed on the tapes alongside the audible programming by  psyops psychologists were clearly perceived by the subconscious minds of the Iraqi soldiers and the silent messages completely demoralized and instilled a perpetual feeling of fear and hopelessness in their minds.
Then there is the suggestion of using Voice To Skull technology in Afghanistan under the moniker “Voice Of Allah” a few years back under the George Bush administration. That plan also included the broadcasting of a hologram image of what Allah was depicted to have looked like.  Further, there was a plan years prior to do the same thing to other Arab nations.
“The Gulf War hologram story might be dismissed were it not the case that washingtonpost.com learned that a super secret program was established in 1994 to pursue the very technology for application to PSYOPS.  The “Holographic Projector” is described in a classified Air Force document as a system to “project information power from space … for special operations deception missions,” The Washington Post wrote.
Steven Corman, writing at the COMOPS journal, described his own encounter with this technology:
At a government workshop some time ago I heard someone describe a new tool that was described as the “voice of Allah.” This was said to be a device that would operate at a distance and would deliver a message that only a  single person could hear. The story was that it was tested in a conflict situation in Iraq and pointed at one insurgent in a group, who whipped around looking in all directions, and began a heated conversation with his compatriots, who did not hear the message. At the time I greeted this story with some skepticism.
Holosonic Research Labs and American Technology Corporation both have versions of directed sound, which can allow a single person to hear a message that others around don’t hear. Holosonic sells a technology called “Audio Spot Light,” while ATC sells the Long Range Acoustic Device. DARPA also has its own sonic projector. Intriguingly, Strategy Page reported that troops used LRAD as a modified Voice of God weapon:
It appears  that some of the troops in Iraq are using “spoken” (as opposed to “screeching”) LRAD to mess with enemy fighters. Islamic terrorists tend  to be superstitious and, of course, very religious. LRAD can put the  “word of God” into their heads. If God, in the form of a voice that only  you can hear, tells you to surrender, or run away, what are you gonna do?

CNET once also reported on the technology, noting that users don’t hear sound through their ears; instead, the sound resonates and reverberates inside the person’s head … except in that case it was used for advertising.

The folks who heard the ad for A&E’s TV show “Paranormal State” emitted from a billboard in New York City’s Greenwich Village must have  thought it was pretty weird. As they walked into the targeted area they were exposed to highly focused sound, picked up not by their ears, but by their skulls. The otherwise inaudible sound waves are experienced via  bone conduction–the sound resonates inside the passerby’s head.
You can watch the latest sound beaming technology by Noveto Systems in the video below reviewed by Associated Press.