All my advice comes from 50 years of personal Treasure hunting and recovery experience, spoken honestly. No one is obligated to accept my advice. Asinine questioning, and subtle negative inferences I will consider to be intentional provocation.
In the case of what I believe is pseudo science, appeals to authority do not impress me. As for asinine questioning, our conversation was fairly straightforward:
You: "Make sure to turn up the volume on your cell phone all the way when generating frequencies."
Me: "Your cell phone probably doesn't generate an accurate frequency via its audio output."
You: "The audio isn't important."
Me: "Then why did you tell people to turn it up?"
You: "I've been doing this for 50 years."
Me: "Not with a cell phone, you haven't." (Okay, I just added that last part as a joke. It was not really part of our conversation. I was totally going to go there though, so I'm leaving it.)
The annoyance that my "asinine" questioning is provoking is likely cognitive dissonance. If you're not familiar with the term, Google it for a good read. It's part of the human condition, but surprisingly few humans have ever taken the time to learn about it. It only came to my attention last year, although I'd experienced it countless times before that. I'd known something about it on a subconscious level, but I'd never really sat down and read about it. Now I know why approximately half of America is melting down on a daily basis, and why people sometimes get really pissed off for incomprehensible reasons on the internet.
In my way of thinking, common sense logic, and science, dictates that a frequency, can be broadcast for great distances without the addition of audio (amplified sound you can hear).
Aha! Science! I love science! Now we're talking!
By your way of thinking, common sense logic, and science, what exactly is your cell phone doing while it's running a frequency generator app? Is it the same thing as a function generator? Given that the frequency seems to be pretty important (but at an electrical level, not an audial level), would a function generator not be a far better choice for this sort of job? Along with that last point, is the shape of the waveform itself unimportant, and if not, would you want to know what it looked like?
Serious questions. I'm not being asinine here. You've given this matter some thought, but I want to see how far down that rabbit hole you went.