Other entrainment methods sometimes used include autopan modulation that moves sound in an 180º arc to create a desired tone. Harmonic box entrainment, invented by James Mann, uses a layering of binaural and monaural tones that alternate between ears, requiring headphones. Sound modulation and filtering, amplitude modulation, and pitch panning use diverse sounds to create rhythmic pulses matched to the desired brainwave frequency. 

That is a general assumption people make but there isn’t really much science to back it up. What we do know though is that isochronic tones are ineffective below 4hz, and possibly a bit higher. So for theta and delta entrainment you are best off with binaural beats. In my experience binaural beats will be very effective all the way up to around 40hz.

With digital upgrades, Berger’s machine is still in use today, known as an electroencephalography machine, or EEG. Berger used his machine to study the brains of psychologically normal and abnormal people and discovered the first brainwave, called the alpha wave and also known as the Berger wave, along with the faster beta wave, which he observed suppressing the alpha wave when subjects opened their closed eyes. 
SPEAKER: You know those people who always seem to be smiling? What's their secret? Turns out a lot of the smiles come from saying sayonara stress. Want in on that action? Well, here are three ways to stress less so you can smile more. First up, play your stress away/ why should kids have all the fun? Your boss might not let everyone out for recess, but you can find 15 minutes every day to do something you really enjoy. Go to a driving range. Play ping pong, cards, or board games. Just keep it friendly. Remember, winning isn't everything. Number 2. Give it up for pet power. Have you ever seen anyone looking stressed when playing with an adorable puppy? Neither have we. Interacting with animals has been proven to lower stress in almost everyone. Simply petting a dog or a cat lowers your blood pressure considerably and reduces levels of the stress-causing hormone cortisol. So pet your pooch. Don't have a pet? Borrow a friend's, or visit a local shelter for some much-needed cuddle time. And the number-one way to stress less? Laugh it off. How does laughter love thee? Let us count the ways. Laughter fills your body and lungs with oxygen. It makes your brain release Mr. And Mrs. Happy Hormones, the endorphins. It bolsters your immune system and helps you, well, be well. It also helps your brain release natural pain relievers, and may even stop painful muscle spasms. It's true. He who laughs best stresses less. So learn to play, adopt a stray, and laugh away. You'll feel great. And it will show.

If you’ve used brainwave entrainment and experienced any benefits, feel free to share your experience in the comments section below. Be sure to discuss why you believe the entrainment was effective and/or whether you think it could’ve been a placebo effect. I’ve played around with the products and feel as if they are great for relaxation enhancement, inducing a temporary perceptual change (i.e. altered state of consciousness), and arousal reduction.
Proceedings of the 9th Conference on Interdisciplinary Musicology – CIM14. Berlin, Germany 2014 BINAURAL AUDIO RELAXATION TECHNIQUES FOR PEOPLE WITH ANXIETY AND STRESS Geraldine Molina, Emilia Sainz, Levi Serrano, Santiago Rentería, Diana Urquiza Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Santa Fe Correspondence should be addressed to: rosas_ger@hotmail.com, dianauf@itesm.mx Abstract: Since the beginning of the 21st century, there has been a great development in different studies related to encephalography and the psychological consequences of binaural audio. The objective of this paper is to analyze the effects of binaural audio as a relaxation method for people that suffer anxiety and stress. The study took place at ITESM, Santa Fe Campus, where twenty participants around 21 years old took part of the study. They were divided into two groups, Experimental and Control. The first one listened to the Theta binaural stimuli and the second one listened to a stimulus with nature sounds (birds and wind). The results show that the experimental group got to conscious relaxation. The control group had an unconscious relaxation (sleep), but when the stimuli stopped they recovered their stress level, for some participants it increased. 1. BACKGROUND At the end of the 19th century, Pierre Janet, a French psychologist, discovered that his patients relaxed when they were exposed to rhythmic light patterns. Hans Berger showed in 1924 that brainwaves could be read and studied through an encephalogram [2]. The first studies were done using visual stimuli, while later studies were done using sounds [3]. Brainwaves are caused by changes in the electric tension between two points in the brain cortex. The electroencephalogram has been used to analyze neurophysiological relations that exist between mental states and brainwave frequencies. When somebody’s mental state changes from alert to somnolence, low amplitude and high frequency brain waves turn into high amplitude and low frequency [4]. 2. BINAURAL AUDIO Giuseppe Tartini discovered combination tones. These occur when two tones are heard at the same time and the listener perceives a third tone. The frequency of the third tone is calculated by the difference between the first two tones, as shown in equation 1. (∆   ) [8] (1) The superior olivary complex integrates the phase differences, which makes possible the perception of the third tone. For example, if the left ear hears a 400Hz tone and the right ear a 410Hz tone, the listener will perceive a 10Hz tone [9]. This third tone is also known as binaural frequency. The binaural frequency is directed from the superior olivary complex to the reticular formation and the brain cortex, where the electroencephalogram can read its effect. The Frequency Following Response (FFR) phenomenon happens when the frequency read by the encephalogram is equal to the combination tone frequency. When this happens, the frequency resonates in the brain stimulating the reticular formation inducing different psychological states. Brainwave bands and psychological consequences are shown in Table 1 [16]. Table 1: Brainwave Frequencies and Psychological Consequences Brainwaves Frequency (Hz) Amplitude (μV) Mental StateDelta 0.1 - 3 20-200 Consciousness is lost, sleep without dreams Theta 4 - 7 20-100 REM Sleep, meditation, and Creativity Alpha 8 - 12 20-60 Conscious Relaxation Beta 13 - 40 2-20 Concentration, Alert, and cognition (High levels are associated with anxiety) It has been proved that delta sound waves in binaural audio therapy have anxiolytic effects on patients with pre-surgery anxiety [7]. Theta binaural sound waves are also helpful with relaxation and anxiety reduction [11]. According to the results presented by the company Regus, in Mexico, 75% of employed people suffer from stress and anxiety. These cause social, health, and economic problems at the same time that productivity decreases [5]. According to the Mexican National Labor Organization, stress means that the GDP decreases from 0.5 to 3.5%. Stress leads to anxiety, irritability, fear, depression, suicidal thoughts, and lack of concentration. Some other symptoms are headaches, nausea, dizziness, muscular tension, insomnia, and tachycardia [6]. There are different techniques to induce relaxation like meditation. New relaxation techniques with binaural audio have been developed through Neurosciences. 3. OBJECTIVES • Evaluate and analyze binaural audio therapy effects (Theta frequencies) on people that suffer anxiety and stress (Students at ITESM), in order to induce relaxation and reduce anxiety. • Determine if the binaural therapy induced relaxation in the experimental group and compare the results to those from the control group. • Through the STAI test and the electroencephalogram results, determine which stimulus is more efficient. 4. HYPOTHESIS Hi: Frequency Following Response phenomenon will take place, as Delta and Theta bands will share frequencies with the combination tones. Hi: Beta brainwaves will show up when the stimulus begins, as they are related to concentration and alertness. 5. EXPERIMENT Twenty participants were randomly divided into two groups, control and experimental. The first group listened to sounds of
This session shifts from the 14Hz sensormotor rhythm through beta to 40Hz gamma, and repeats the pattern over and over, constantly “revving up”the mind with each repetition. The process is stabilized with a 10Hz background alpha beat, allowing the brain a place to relax instantly, whenever a let up allows. Use this session any time, and for as long as required to get the job done. Take in a High Energy Espresso on long-hauls for a welcome lift. Works without headphones, but the best benefits can be found with them. The session finishes at a fast, revving 18Hz beta. For use mainly with eyes open, engaged in activity - with benefit to be gained from periodically closing your eyes briefly and relaxing.