gateway process · hemi-sync · cia memo

The Gateway Process is Hemi-Sync in headphones. An Army memo named that training.

JM Thomas · 21 August 2026

You wanted the CIA file to name a way in.

The Gateway Process is an Army write-up of a headphone training, and the CIA later released that write-up in its reading room, so people call it the CIA file. The Gateway Experience is the training itself, a set of tapes you listen to with headphones. Hemi-Sync is the sound method on those tapes: two slightly different tones, one in each ear. A binaural beat is the difference you hear when the two ears get two tones. Frequency Following Response is the brain tending to follow a repeated sound. You wanted the file to name a way in, and McDonnell named that training.

What is the Gateway Process?

The Gateway Process is the name on an Army memo dated 9 June 1983. Wayne McDonnell wrote it for the US Army Operational Group at Fort Meade, and his title is Analysis and Assessment of Gateway Process. The later public file number is CIA-RDP96-00788R001700210016-5, and a CIA memo here means an Army write-up that later showed up in the CIA reading room.

The Gateway Experience is the training he assessed, and he named it a Hemi-Sync training system. He did not write a trial count. The letter n is how many people sat in a counted group, and the memo lists none.

How does Hemi-Sync work?

Hemi-Sync is two slightly different tones, one in each ear, so you hear one tone on the left and a neighbor tone on the right. A binaural beat is the difference you hear when those two tones meet in your head. Hertz, written Hz, is how many times the sound shakes in one second, and McDonnell called that gap a beat frequency. He then named Frequency Following Response, the brain tending to follow a repeated sound.

You need one tone in the left ear and one tone in the right ear, and you get that split from headphones. If you play both tones from one speaker, they mix in the same air. The Hertz pair on the hero picture is a sketch, and McDonnell did not lock that pair as a measured trial.

What did McDonnell write in 1983?

McDonnell named the Gateway Experience a training system that uses Hemi-Sync, and he wanted the left and right sides of the brain to match in amplitude and frequency. Amplitude is the size of the wave. Frequency is how fast the wave repeats. McDonnell quoted Melissa Jager, a Monroe Institute trainer, for that matched state, and he listed Itzhak Bentov and Robert Monroe in the bibliography.

You can read the memo as a PDF. Open the Black Vault copy, or open the same file number on the CIA reading room page. You wanted the file to name a way in, and he named headphones, two tones, and a training system.

What did Dabu-Bondoc find in surgery?

An RCT is a trial that puts people into groups by chance. Susan Dabu-Bondoc and colleagues later ran Hemisync sounds in surgery rooms, and they counted pain medicine and sleep medicine.

In 2010 they published a brief report in Anesthesia and Analgesia. They put twenty people on Hemisync, twenty on music, and twenty on a blank cassette, a tape with no sound, so they still wore headphones. Fentanyl is a strong pain medicine used in surgery, and the Hemisync group used less of it during surgery. P less than 0.05 was the cutoff they used to say the groups differed. VAS is a pain score from 0 to 10, and that score was lower at one hour, P=0.02, and at twenty-four hours, P=0.005. People also left the hospital earlier, P=0.048.

In 2003 the same first author asked a different question, with thirty-one people on Hemisync and twenty-nine on a blank cassette. Propofol is a sleep medicine used in surgery. BIS is a forehead number that tracks how deep the sleep medicine is. With that number held, induction propofol was 2.49 plus or minus 0.59 milligrams per kilogram against 2.60 plus or minus 0.59, P=0.48. Maintenance was 0.141 plus or minus 0.02 against 0.146 plus or minus 0.04 milligrams per kilogram per minute, P=0.62. Milligrams per kilogram is how much medicine you get for your body weight. They did not cut propofol.

What did later trials add?

Lewis and colleagues published in 2004, and they ran a double-blind RCT, which means neither the patient nor the recorder knew who heard what. People having weight-loss surgery used 0.015 against 0.024 micrograms of fentanyl per kilogram per minute, P=0.009, and people having back surgery used 0.012 against 0.015. The abstract does not lock how many people sat, so that count stays empty here.

Gantt and colleagues published in 2017 in the Journal of Nursing Scholarship, and seventy-four military service members heard music with a theta binaural beat, or music alone. Theta is a slow band people use for a beat inside music. Heart-rate variability moved, which means the time between heartbeats changed. Gantt watched a beat inside music, not a Monroe tape.

Is Hemi-Sync the same as a binaural beat?

Hemi-Sync is a product name for two slightly different tones, one in each ear, and a binaural beat is the difference you hear. An isochronic tone is one tone turning on and off. If you want that split, open the binaural versus isochronic page.

If two tones in headphones bring unusual distress, talk to a clinician. McDonnell wrote a memo, and the 2010 and 2003 papers are anesthesia trials.

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