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HOWTO> making your own binaurals.

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  • HOWTO> making your own binaurals.

    So you want to make your own binaurals? Great! I'm really looking forward to hearing them and swapping ideas with everyone. Tell you what, I'll teach you how to make your own in ten minutes. Sound good?

    So a good online tutorial includes a link to any required software, which ideally should be free and open source. Here's a link for Audacity, it's cross platform and it includes actually one of only a few tone generators available that allow you to generate hertz values to within two decimal places. So binaurals with 0.01hz accuracy of a desired frequency. Free. Yeah, I love you guys too, but don't thank me, thank the incredible community of developers and hobbyists at Sourceforge, those people rock. Bookmark Sourceforge, the depth of software they have defies generalisations.

    The next thing is a good how to has is instructions you can work along with. So download and install copy of audacity and we'll see you back here in a minute. All done? OK.

    Open up audacity. On first run you'll have to click through some set-up stuff I haven't done for years and can't remember, but it's all very straightforward, you're just telling the software what sound hardware to use, it should default to the one nominated in your OS. Click ok, if nothing busts into flames, TURN DOWN YOUR VOLUME A BIT and proceed.

    What you're looking at is a wave editor without a wave in it. Let's get cracking. click anywhere in the big gray blank area, then navigate in the menus to GENERATE>TONE as shown here.

    Now you see an audio track (currently silent,) default 30 seconds long and the tone generator window. Note you can nominate waveforms to use... be careful with square waves, speakers tend to fry voicecoils, shake spiders to pieces and perforate cones when exposed to big square waves. You can use them at your own risk, at low amplitude (volume) and start with playback turned down and turn it up and stop before your speakers start "farting." That's a technical term, you'll just have to trust me on that. Speakers simply aren't designed to do the hard gated on-off of a square wave, even at low volume. You'll reduce the life of your speakers if you get a square wave wrong, perhaps even just blow them to bits.

    So in the tone generator window, I've selcted to generate a sine wave, 30 seconds long, with a tonal value of 444.44hz at an amplitude of 0.9 (90% of full volume. Pro tip, you can turn a clean signal up until it distorts, but you can't turn a distorted signal down and make it clean again. 90% amplitude values are fine.) This tone will be in mono. Click "generate" and you have your first tone.

    Next, Click in the gray area below the tone you've just created to de-select that track. (if you don't and create a new tone, it will just over write the first on.) Now generate a second tone. This time I've gone for 30 seconds, tonal value of 444 hz even, and amplitude again at 0.9 (it should default to the last value once you've set it.)

    Now you can see two mono tracks, pan one hard left and one hard right, (track panning is on the far left of the audio track, at the bottom of the track controls. see L_______R ) hold down the shift key and press the spacebar to commence looped playback.

    You should here that classic binaural beat, very slowly, one oscilation about every two seconds (1hz, 1 cycle per second. 10hz = 10 cycles per second. 0.5hz = one cycle every two seconds.) Now to create a .wav file of the binaural, just go to file, export as wav and nominate a diorectory and file name to export your binuaral to. And that's it, that's how you make binaurals with free software. You can make them any length but I'd advise generating 20 minutes of tone if you want a 20 minute binaural, looping can get very tricky with sine waves.

    If you wanted to get tricky, you could record affirmations into a third track in audacity using your computer's microphone and leave that track panned to the center and then bounce. Or you could add a second set of complimentary tones with a different rate of disonace to create a bi-phase binaural. Or add white noise, not that I'd advise it, white noise is not a carrier tone, it's just sensory garbage, clutter. Look at what happens to a beautifully complex binaural sine wave when you add a track of static and just consider, from a purely visual poit of view, if it's a change for the better. the only signals I add noise to are snare drums and guitars to make them crunchy. I don't want crunchy binaurals giving me crunchy EEG entrainment though.

    Given the primary tonal value, the most important part of the tone generation process, is expressed numerically, there is certainly scope to play with the numbers. I have a predeliction for 2s, 4s and 8s myself. Your speakers won't be able to generate a tone under about 30hz. Your soundcard may glitch out at less than 8hz. 40hz is very, very low, almost imperceptible to hearing but remember the binaural's rate of disonace is not a function of it's carrier tone but of an acoustic phenomenom called phasing. Pan your speakers hard left, then hard right while a binaural is playing. Oh! where's the beat go? Well, the speakers don't generate it. the meeting of the two tones in the space around you is what generates it, which is why it's possibly to produce oscilations well below the range of what your speakers are capable of producing which you can still hear, because what you hear is a product of the carrier and modulator tones, the "beat" is a function of acoustic dynamics. Cool, huh. A sound that doesn't exist except as a function of an interaction between two other sounds.
    Last edited by noises; 05-13-2009, 03:28 PM.
    “When fascism comes to America, it will come wrapped in the flag and waving a cross.”

  • #2
    Very cool! Thanks!
    My reality does not equal your reality, but my reality is neither > nor < your reality.


    • #3
      Just a note, by default, Audacity produces MONO tracks. Go to EDIT>PREFERENCES and in the audio input/output tab, change the default recording output drop down box from 1 track (mono) to 2 tracks (stereo,) and apply that change before you try to bounce out a binaural, which MUST BE in stereo to work. As I said, it's been some time since I went through the set-up process, that point slipped my mind until I got home last night.
      “When fascism comes to America, it will come wrapped in the flag and waving a cross.”


      • #4
        Would raising the pitch (increase frequency without changing tempo) of one channel of any song we like to say 4Hz produce binaural beat?


        • #5
          First you'd have to split the stereo recording into a left and right mono track. then, yes, pitch adjustments to one of the two tracks will produce dissonance. But that dissonance will be effected by the psychoaccoustic dynamics of the music. If you heard a binaural beat at all, it would be intermitent, as your brain would naturally focus instead on things like vocals and sharp percussive transients like snare drums, and mess up the phasing. a pure sine wave is much, much better.
          “When fascism comes to America, it will come wrapped in the flag and waving a cross.”