Is there any hard evidence for the effectiveness of brainwave entrainment programs like lifeflow, clear-mind, holosync or hemi-sync?

I researched info on: Holosync once and could never get a randomized controlled study. It doesn't mean there is no benefit. Let's take holo sync. The way to test it is to use music without activity underneath. U would then do comparisons on those with the music vs. Music and technology. The gold standard is the randomized study, no one knows who got the technology. This would take a great deal of time and money.