[deakon]

I've been having a problem getting a grip on frequency's. Normal hearing range for humans is 18hz - 20khz. How do we hear frequency's below 18hz. Beta is 18hz., delta is .5hz..
After exploring the forum looking for answers, "can't find any", I get the idea that I'm the only one that doesn't understand this. Some HELP please!!
deakon

[CraigT]

This is indeed a confusing state of affairs. Our hearing gear is only good for 18-20k, but there's no problem hearing things that occur more slowly.

The "pitch" is the basic bare waveform, also referred to as a "carrier". That is the "sound" we hear when we listen to, say, a 180Hz sine wave.

We can take this bare sine wave and do any one of several things to it.

If we directly mix it with a 185Hz sine wave, we will hear something kind of 180-5Hz-ish "throbbing" as the 180 cycles per second grates against the 185 cycles per second - a poor analogy is two mismatched gears. This is a monaural beat.

If we play the 185Hz into our left ear, and the 180Hz into our right ear, the interaction takes place internally. There's a few different theories about the mechanism, but the end result is that you hear much the same thing as a monaural beat, but you perceive the sound formed between your ears. We have a binaural beat.

The next thing you can do to your 180Hz sine wave is chop it up into pieces. Suppose we want the same 5Hz beat as before. Feed the sinewave into a switch that turns on for 100ms and off for 100ms five times per second. You'll hear a 100ms burst of 180Hz five times every second - 5Hz. And this is an isochronic beat.

Lots of variations on the theme, each with its virtues. Have fun

Cheers,
Craig

[NriQk]

CraigT, on 07 February 2010 - 03:13 AM, said:

This is indeed a confusing state of affairs. Our hearing gear is only good for 18-20k, but there's no problem hearing things that occur more slowly.

The "pitch" is the basic bare waveform, also referred to as a "carrier". That is the "sound" we hear when we listen to, say, a 180Hz sine wave.

We can take this bare sine wave and do any one of several things to it.

If we directly mix it with a 185Hz sine wave, we will hear something kind of 180-5Hz-ish "throbbing" as the 180 cycles per second grates against the 185 cycles per second - a poor analogy is two mismatched gears. This is a monaural beat.

If we play the 185Hz into our left ear, and the 180Hz into our right ear, the interaction takes place internally. There's a few different theories about the mechanism, but the end result is that you hear much the same thing as a monaural beat, but you perceive the sound formed between your ears. We have a binaural beat.

The next thing you can do to your 180Hz sine wave is chop it up into pieces. Suppose we want the same 5Hz beat as before. Feed the sinewave into a switch that turns on for 100ms and off for 100ms five times per second. You'll hear a 100ms burst of 180Hz five times every second - 5Hz. And this is an isochronic beat.

Lots of variations on the theme, each with its virtues. Have fun

Cheers,
Craig

This is a very interesting topic. I'm glad u shared this with everyone Craig. I dont completely understand how the entrainment proccess works in technical terms, but I do know that with all the techniques provided with Transparent software, together it is an amazing process. Deakon, are you new to using entrainment software?

[deakon]

NriQk, on 06 February 2010 - 10:38 PM, said:

This is a very interesting topic. I'm glad u shared this with everyone Craig. I dont completely understand how the entrainment proccess works in technical terms, but I do know that with all the techniques provided with Transparent software, together it is an amazing process. Deakon, are you new to using entrainment software?

Yes, I've had NP2 for a few months now.
And, Thank you Craig for your input.
Then from what I can understand, when we hear a delta tone of .5hz, what we are hearing is the binaural or monaural beat.
All the different frequency's in Beta, Alpha, Theta, and Delta are binaural or monaural beats. And isochronic beats do the same thing.
I hope that's right because I understand that.
deakon

[CraigT]

Yup. That's pretty much it. If you're hearing something less than about 20Hz, you're either hearing a beat created out of two or more frequencies, or you are feeling vibrations.

Just to be clear, though, the brain rhythms are the low frequencies - binaural, monaural, isochronic, etc. are just ways to provide audio stimulus at those frequencies. Photic stimulus doesn't require any of this - our visual system responds directly to brain rhythm range stimuli. And of course, once you get to high beta/gamma (above 20Hz) it becomes possible to use a plain pitch.

Cheers,
Craig

[deakon]

CraigT, on 07 February 2010 - 02:39 PM, said:

Yup. That's pretty much it. If you're hearing something less than about 20Hz, you're either hearing a beat created out of two or more frequencies, or you are feeling vibrations.

Just to be clear, though, the brain rhythms are the low frequencies - binaural, monaural, isochronic, etc. are just ways to provide audio stimulus at those frequencies. Photic stimulus doesn't require any of this - our visual system responds directly to brain rhythm range stimuli. And of course, once you get to high beta/gamma (above 20Hz) it becomes possible to use a plain pitch.

Cheers,
Craig

Thanks once again Craig. I'm good now, for sure.
deakon

[Jay_NOLA]

Craig covevered everything.
I just want to add that the confusion between pitch and beat rate is very common. If you look at frequency lists for entrainment they often don't distinguish between the two.
Some companies that make "snake oil" entrainment devices in the past have made tapes that couldn't deliver te required pitches they were reporting to deliver due to numerous reasons.
The FAQ section of the NP2 help guide does talk about the human hearing question in the Brainwave Stimulation (Entrainment) section.