hello, is there someone who is very knowledgeable about using audacity effectively can help me?
I really want to make a subliminal message, but not a silent subliminal because it’s not good for my ears.
And I found this after I research https://patents.google.com/patent/US5170381A/en
Can someone teach me how to make subliminal according to edon taylor’s patent? Thanks 
A human voice reduced to a bandwidth of 10/50/80Hz is unintelligible. [cf. a telephone uses ~4000Hz].
The authors of US5170381 have a couple of other patents:
for a coin-dispenser & a turfing-machine, (i.e. they’re not brain-surgeons).
Just because a patent exists does not mean the technology actually works, e.g.
From time-to-time subliminals come-up here on the forum. You can search and you might find some answers but most of us here (including me) seem to be skeptical “scientific types” so you probably won’t get much help. 
You might find some instructions on a website oriented toward subliminals, or maybe a psychology website. Then if you have questions about how to do something specific with Audacity (like how to frequency-modulate, or amplitude-modulate, or pitch-shift a recording, etc., you can ask here. We are happy to help if we know exactly what you want to do.
…My “favorite” subliminal technique is to simply mix a quiet recording with a louder recording that drowns-out the “secret message”. The louder sound can be white noise, pink noise, music, etc. Natural sounds like waves & rain usually have quiet parts where the subliminal might leak-through, and with music the same thing could happen if you have sublimibals between songs.
I like this method because you can later subtract-out the loud sound and boost the volume revealing the message (if you are careful about the process). This also “proves” that a secret message actually exists! It’s also easy to do and easy to understand how the technique works. Some other methods might end-up mangling & destroying the message,
Whatever method you choose, do not use lossy compression (like MP3), Lossy compression works by throwing-away little details you can’t hear and there’s a good chance it will throw away the subliminal. (Although it doesn’t matter THAT much if you lose the subliminal since you can’t hear it anyway! 
)
Can you help me how to make it?, I want to mix subliminal audio just below the threshold of the music.
Yes I think so too, because many manufacturers make only with mp3, but I’m not sure.
You mean the simple non-patented “drown-out” method, right?
“just below” audibility could be tricky and it will probably require some trial-and error.
I assume you have a music file and a subliminal file…
- Open the subliminal file, select the whole thing and then use the Amplify effect at -20dB to reduce the volume. (If that turns-out not to be quiet enough go back and start-over a bigger negative number.)
- Use File → Import to import the music file into the same project.
If you Play in audacity with both files open they will mix and that will give you an idea of what you’re going to get.
Now, if you want to reveal the subliminal message -
- Open the original music-only file.
- Use File → Import Audio to bring the subliminal mix into this new project.
When you play the file the inverted music will mix with and cancel-out the music in the mixed-file and you should hear the subliminal message (quietly since you reduced the volume before mixing).
You can export and you’ll get that new “mix” with just the recovered/decoded message. Then you can open and amplify that if you wish.
…I hope I didn’t miss any steps.
There is one more thing that might improve quality… The mix of the music and subliminal will boost the volume (when you mix you are summing) and that can push your levels into clipping (distortion). It shouldn’t be too bad since the subliminal is low level but you can prevent that if you reduce the music by 1 or 2 dB. Just make sure to save that slightly-reduced file if you want to recover the subliminal because the inverted file has to be an exact copy if it’s going to subtract completely. In fact that’s the issue with clipping… if the mixed file is clipped the music in that file is no longer identical and it won’t subtract completely, The subliminal is distorted and damaged too.
…Sometimes I’ve said “subtract” and sometimes I’ve said “cancel”. But as I also said that mixing is done by summation, When you invert and mix you are “adding a negative to a positive” which is the same as subtraction, and the result is canceled sound.