Stress: In one randomized controlled trial with 108 participants, a single session of alpha and delta stimulation resulted in significantly less anxiety in surgical patients. Another session of theta stimulation resulted in improvement in certain measures of stress. Stimulation with certain frequencies of alpha and beta were reported to provide the most significant benefit for those who are stressed.
One of the most fascinating and beneficial things about Delta brainwaves is their ability to stimulate the release of anti-aging hormones in the body, such as HGH (human growth hormone). Increased melatonin levels are also common in this state, and regular visits to Delta have also been shown to decrease cortisol levels. (Cortisol is a hormone that is released during stressful situations, that has been linked with the aging process.) In a nutshell, Delta brainwaves are very healthy, and until now have only been accessible to us during deep sleep.
Isochronic tones are basically just a single tone with the volume being turned on and off at regular intervals. When you apply the same effects to music or a noise, it’s usually referred to as amplitude entrainment effects (in Mind Workstation anyway). When you apply the on/off effect to music or noise it’s usually done by targeting a specific frequency range in the sound and only turning that part on/off, leaving the rest of the music/noise untouched. What that does is allow parts of the music/noise to play without being distorted/interrupted, making it sound more pleasant to listen to. It produces a kind of fluttering sound as I like to call it and you can adjust the level of intensity.
Let's check in with another expert, chemistry professor Thomas Taylor from the Texas A&M. Taylor hooked a load of students up to an EEG machine (like you see in the movies with the sticky plastic pads with wires stuck all over people's heads) in an attempt to analyse 'synthesis thinking' - which is basically a nerd's way of saying "find out how people come up with new and creative ways to solve a problem".
The Delta waves range from 1-3 Hz; these frequencies can assist in enhancing deep sleep. They also play a big role in boosting the immune system to facilitate natural body healing. The Theta waves have a frequency that ranges from 4-7 Hz. In turn, this brain state can enhance deep relaxation and is known to assist individuals who have poor memory. They are the best frequencies to use if you want to focus or meditate.
Alpha stimulation: Stimulation of alpha waves has been shown to provide stress-relief among employees, is able to provide pain relief, and improve measures of competence and recognition. If you have significant work-related stress, entraining certain alpha frequencies may help you decrease arousal and improve relaxation. Post-surgical stress doesn’t appear to benefit from alpha stimulation.

It may be that you had the volume too loud, but I would expect you to hear the effects of that straight after you’ve stopped listening, not on a day you haven’t used them. It might be something similar to muscle memory, where you suddenly remembered the sound and sensations it gives you as if you were hearing it again. I don’t know how long you’ve been using this type of thing for, but maybe it’s something that will settle down and disappear once you become more accustomed to the sound.
When delta waves are present, our awareness of the external world decreases and shuts off. People with ADD have problems with delta waves occurring when they are trying to focus, and focus and attention become increasingly impossible with stronger delta waves. Studies show a reduction of anxiety, improvements in insomnia, and elimination of headaches when people engage in sessions of delta brainwave entrainment.

Cvetkovic D, Simpson D, Cosic I (2006). “Influence of sinusoidally modulated visual stimuli at extremely low frequency range on the human EEG activity“. Conference proceedings : … Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 1: 1311 – 4. doi:10.1109
I’ve been on the brainwave vibe for about 6 months now, & I’m really diggin’ some results! I find that there are certain frequencies, I guess, that feel right and comfortable to my mind; I also find that I can physically feel the area of my brain that “pure” (no frikkn ocean waves) tones are affecting as I listen to them. This occurs the moment I hear the sound. Kinda like energy, a brain tickle. Spooky & awesome!!
The reported PMS symptoms that improved included: affective lability, anxiety, appetite changes, bloating, breast tenderness, concentration difficulties, depression, fatigue, and irritability. Researchers noted that there was a clear “trend” toward a reduction in social withdrawal as a result of symptoms as well. A total of 49/50 women reported improvements.
However, those with ASD are sometimes also diagnosed with ADHD. Although they are different conditions, some of the symptoms can be intertwined, which it appears may be the case with your grandson. So I would start by trying out my tracks for ADHD. You can try those out for free on my YouTube channel and I’ve put them together in a playlist here: The corresponding MP3 versions for those tracks can be found on my site here: I hope that helps.
EquiSync’s design is based on the 100’s of studies performed on the effectiveness of brainwave entrainment technology, and 1000’s of studies on the powerful benefits of meditation. If you are interested in better understanding the power of this technology and rapidly expanding field of research, then here is a very abbreviated bibliography, a very small sample of the studies out there:
But again, when it comes to subjective experience, and mental evolution, I would have to caution you to take what anyone says with a grain of salt.  Obviously people want to sell these products.  There are some good ones out there and there are some bad ones out there.  There are differences in quality, as well as differences in intent with how the audios are to be used.
With regard to listening without headphones specifically, you might find it irritating if you are someone who suffers from motion sickness, depending on how the track is created. If you were listening to binaural beats, they really need headphones to work properly. If you are in a room and closer to one speaker you may not even hear binaural beats properly, and if sitting off centre in the room generally, that may have unsettled you if you have motion sickness as the tones try to form a beat in your head. If it was just a standard isochronic tones theta track that shouldn’t be irritating if you have motion sickness.

Regular production of Alpha brainwaves ensure that your immune system stays in top shape. This is made possible since they’re able to keep the body relaxed, thus reducing the chances for stress to build up. As a result, your body doesn’t end up producing harmful chemicals which can harm your immune system. By keeping anxiety and stress at bay, Alpha brainwaves reduce your chances of having to deal with stress-induced or anxiety-related sickness.
Hi Rona, thanks for your compliments on my videos and the music I use, I’m pleased you’ve found them helpful. Regarding the pulse-like sound you’ve been hearing, I’ve never had anyone report something similar to that before. I also haven’t heard anyone on brainwave entrainment forums mention it. That is very unusual and because I’ve never come across it before, I’m afraid I don’t know what would cause that.
These sounds in these musical tracks are presented through monaural beats, binaural beats, isochronic tones, or a mixture involving combinations of all three of these modalities, described in detail below. Choose alpha brainwave tracks for calming anxiety and relaxing body and mind, and choose theta tracks for help in getting to sleep and for bringing hidden feelings to the surface. Some people also report out-of-body type experiences when in theta brainwave states.

Brainwaves, or neural oscillations, share the fundamental constituents with acoustic and optical waves, including frequency, amplitude and periodicity. Consequently, Huygens' discovery precipitated inquiry[citation needed] into whether or not the synchronous electrical activity of cortical neural ensembles might not only alter in response to external acoustic or optical stimuli but also entrain or synchronize their frequency to that of a specific stimulus.[16][17][18][19]