Now for something completely different.
Let's talk about entrainment, the process by which wave frequencies in two or more interacting systems with different periods eventually lock into phase. You see it nature, for example, when fireflies start blinking together in unison. You hear it in music when different instruments in a jam session start to vibrate together in harmony. It even happens in our bodies. When you slow your breath, it leads to a slowing of heartbeat and brainwaves.
Now let's talk about binaural beats. Binaural beats are perceived sounds which naturally arise in the brain when two slightly different frequencies are played separately into each ear. It's best explained with an example: if you listen to a 405 Hz frequency (sine wave) in one ear and a 398 Hz wave in the other ear, your brainwaves will start to oscillate towards a frequency of 7 Hz, or the difference between the two sounds. This process happens through entrainment.
Here's the interesting part: while human hearing is limited to an approximate range of frequencies between 20 Hz to 20,000 Hz, brainwave frequencies associated with relaxation, REM sleep, meditation, and deep sleep fall below the 20 Hz threshold.
What this means is that binaural beats can, in theory, be used to entrain your brain to frequencies that fall below perceived human hearing. If you search for brain entrainment on the Web, you'll find a slew of articles, thing for sale, and wild claims. And I know of at least one institute that will gladly take lots of your money to provide you with a life-changing (patented) brain entrainment experience at their facility.
My interest is more casual. I first came across the idea of binaural beats and brain entrainment back in the early 1990s while researching a paper in college. I found the idea intriguing. I played around with an oscilloscope to observe two waves suddenly lock together after growing closer and closer together. I found the idea of it fascinating.
Then, at some point (the timeline is a bit fuzzy), I came across a sound editor called Syntrillium Cool Edit Pro. This was a classy PC audio editor that once, to my surprise, included a somewhat-obscure menu for creating sound files for brain entrainment using binaural beats and pink noise. I tried it. I liked it. While I didn't have any crazy experiences, I did find that some of the files I created were effective for relaxation, meditation, and focus.
As I recall, the brain entrainment submenu disappeared at the next Cool Edit Pro software update after I started using it. I don't know why. Then, years later, Cool Edit Pro was bought out by Adobe. It is now called Adobe Audition.
Fast forward to 2009. While the auditory intrigue of brain entrainment (or, more accurately, the effects of this technique) remains in the speculative and hypothetical range, there are now several choices for the PC and the iPhone/Touch to try this out for yourself. The desktop programs are nice, but these are audio-centric apps that require headphones. It should come as no surprise, then, that the iPhone/Touch apps really shine.
Here's what you can get for your Mac, Windows, or Linux box
<1. SBaGen. (Mac, Linux, Windows) This is a good, free choice if you like to roll your own, are comfortable with the Terminal, and don't mind getting your hands a bit dirty. There are sample sounds for backgrounds you can download at the site. If you want to have some fun, and are the type of person who likes the DIY ethic, try it out.
2. BrainWave Generator. (Windows only) This isn't a Mac app, but I used it in my PC days. It hasn't really changed at all since those days, and that's not necessarily a bad thing. It's like SBaGen, but it has a Windows user interface and is much easier to use. It offers a lot of user control to fine tune frequency settings. It's shareware. It now costs $40 to buy a private license, which is steep for an app that hasn't been updated since 2005.
2. Pzizz. (Mac, Windows) I tried the trial when it first came out a while back. It uses binaural beats, but also mixes in sound effects, people talking, and music in some sort of fancy algorithm. Many people like it. I didn't care for it. Why? I can only say it's a matter of personal preference. I preferred the free SBaGen. I preferred it, that is, until I found the iPhone apps.
But this was made for the iPhone/Touch
1. Binaural Beats. Free. Offers presets with nice background music. You can also try Easy Relax Ultimate from the same company for $2.99. I found the free Binaural Beats app worked for me as a relaxation and sleep aid.
2. AmbiScience. Try the full app for $.99 or the Lite free version. For the price, the $.99 app is nice application that does the job well. It includes entrainment for relaxing, meditating, focusing, or sleeping. The interface is pleasant. I bought it. I use it.
3. mind Wave. The cost is $1.99. Haven't tried this one. It includes some interesting choices such as headache treatment, weight loss, and creativity boost. I'm a bit skeptical, but it's not very expensive. You can also opt for "mind Freek," a separate app from the same developer that also costs $1.99, and offers more esoteric settings such as astral projections, out of body experience, etc. Sounds wacky, and results may vary...but it's cheap and may be fun to try. I think I'll probably pass.
There you have it. Does this work, or is it pseudoscience? The truth is likely somewhere in between. I will vouch for it as a tool for sleeping, meditation, relaxation, and focus. What is certain is it costs next to nothing to try aural brain entrainment. So why not?