If you want to do some personal research with Binaural and Isochronic Beats, it's easy to create your own via the freeware program Audacity.
You change your mental state with a monotonous beat. This idea is very old. Shamans used a drum for entering a numinous state which enables them to enter the spirit world even 9000 years ago. They mostly use a beat of 210 bpm which equals 3.5 Hz and entrains a low theta state in the human brain.
Monaural and binaural Beats
If two tones of similar frequency interfere there will be an effect in which the both tones extinguish or amplify their intensity which results in the sound of a beat of the difference of the tones.
If you use stereo headphones the beat will originate in your head. That makes the binaural beats more effective than the monaural ones.
My aim is to create a sound file which entrains the frequencies of 3,8 Hz, 9Hz and 16Hz in my brain.
But why these frequencies?
Low theta waves are linked with journeys into inner worlds. 3.8 Hz results from my personal preferences. The usual 3.5 Hz which are used in shamanic techniques I considered a little too slow, 4 Hz too fast.
9 Hz, says Thomas Yuschak, are linked with lucidity in dreams. Further research supports this thesis.
The 16 Hz I just guessed to be linked with concentration.
In some lucid dreams beta and gamma waves are increased in the brain.
I chose the isocronic track to have a frequency of 9 Hz. In Audacity I use the option of 'create' - 'click-track' with parameters of individual click duration = 80 msec, click sound: noise, and midi pitch strong/weak pitch of 100 or 99. Maximum frequency is 270 bpm as there is a limit for the maximum frequency. After creating I double the speed. You may play around with all those parameters just as it sounds good to you. Finally I use the equalizer to make the sound less monotonous.
You create a new soundtrack and create a single sine tone of a pleasant frequency. Most people like frequencies in the range of 100 to 400 Hz best.
Then you create another soundtrack and create a new Sine tone of the just created frequency plus the frequency you want to entrain.
You may start e.g. at one soundtrack with 150 Hz and on the next soundtrack you use 166 Hz which entrains a medium beta state.
You even have the possibility to create a dynamic tone which alters the frequency with time.
That is good if you want to start with the entrainment at a certain frequency and slightly change it to another.
It is important to make sure that one of the track is completely on the left channel and the other one on the right to create the binaural effect.
The monaural effect is a mix of isochronic and binaural beats: It is based on the effect of interference but not in stereo so the beat is not generated within one's head. That makes this effect the weakest.
So I use the phaser or tremolo effect of 3.8 Hz on the sine waves of the binaural portion.
So we're done.
You may export this track as an MP3-file you should make sure that the conversion rate is bigger than 196 kbs.
Of course this article is purely for informational purposes and you experiment at your own risk.