I have heard of holosync or hemisync frequencies that induce theta waves but
never in conjunction with beats. Also I don't know if anyone ever heard the
emre: dark matter compilation but it had the highest and lowest frequencies I
had ever heard on an album. Sub notes so low that you can't hear them but when I
took the cover to my sub-woofer off, I could see that the rubber lining was
moving an inch in each direction, in and out, at a rate of about once per
second. Also, a girl I went to high school with mixes for dance clubs sometimes,
she said she's been experimenting with mixing the brown/black note in the
background of other tracks to see if she can make anyone sick, she says it has
worked before.