Write the subliminal content. The content should be short, simple, actionable, theme-based and repetitive. You need a very clear objective to the communication. For example, subliminal content to grow confidence may follow this pattern: "I am confident. I believe in myself. I have skills and tools to assert myself in any situation. People look up to me and I inspire confidence in others. Each and everyday when I wake up I am more confident than ever before." Repeat these and similar phrases on loop during the recording.
Download and install audio recording software. There are no native Windows programs capable of completing this task. Adobe Audition, Cubase and Sony Sound Forge are all excellent programs which can easily embed subliminal messages. All programs have a similar interface and offer the same functionality.
Open the program. Navigate to the folder where the existing subliminal audiobook file is stored. Click and hold on the file and drag it into the audio editing program. The existing audiobook will now show up as a track in the audio program.
Press the "Record" button in the audio program and record the subliminal messages that will be looped in the background of the audiobook. The program will automatically add another track for the recording. When finished recording press the "Stop" button.
Repeat the subliminal audio track. The audiobook track is likely to be significantly longer than the subliminal track. You will need to loop the subliminal track or repeat it for it to span the entire length of the audiobook. Right click on the subliminal track and click "Copy." Right click in the free space in the "Timeline" right next to the original subliminal recording and click "Paste." A copy of the subliminal track will be placed there. Repeat this process until the subliminal tracks equal the length of the audiobook track.
Adjust the volume. The volume for the subliminal track must be perfect to maximize the effectiveness. It must be barely audible to human ears, loud enough for the user looking for it to notice something but not loud enough for them to notice what is being said. Adjusting the volume will require trial and error and a keen ear. Click on the "Volume Control" for the subliminal track and lower it. Lower it and play the track. Continue to adjust the volume for this track until it is perfect.
Export the audiobook with subliminal messages. Click "File," "Save As," then navigate to a directory where the new file should be saved to. Enter a "File Name." Click "File Type" and select an appropriate file type; "mp3" and "wav" are commonly used. Click "Save." The program will now export the newly edited audiobook with subliminal messages. Navigate to the new file after it is saved and preview it.