People who handle stress well tend to employ what stress experts call an "optimistic explanatory style." They don't beat themselves up when things don't work out in their favor. So instead of using statements that catastrophize an incident, like "I'm a complete failure," they might say to themselves, "I need to work on my backhand." Or they'll transfer blame to an external source. Rather than saying, "I really blew that presentation," it's, "That was a tough group to engage." Replace the word "expect" with "hope." Expectations can only be used for those things over which you have the greatest personal control. You can expect to quench your thirst with a drink of water. You cannot expect to get the job you just interviewed for. You can hope to get it.
The mechanism for this is that when your eyes or ears are exposed to a particular frequency of pulses or beats, the thalamus first distributes this information to the entire brain, including the visual and cerebral cortex where neural activity begins to synchronize to the incoming frequency, producing hemispheric synchronization and a balance of brainwave activity across the brain.
While binaural beats are the most common technique we use for producing brainwave entrainment music, we do use other brainwave entrainment techniques such as isochronic tones, monaural beats and amplitude modulation. If these techniques have been used then you will find them mentioned in the written description of the music productions that include them. If not mentioned, then you can assume that binaural beats are the only brainwave entrainment technology in use.
When stress attacks, it can feel like your whole world is crashing down. Remind yourself what’s good in your life with a quick gratitude round-up. “Studies show gratitude techniques like counting your blessings can be a significant stress reducer,” Dr. Serani says. “Gratitude research reports that those who utilize daily gratitude reflections have higher levels of positive emotions, life satisfaction, vitality, optimism, and lower levels of depression and stress.” Reminding yourself of the good things in life can put stress in perspective. “Studies show that cultivating an optimistic mindset can help you maintain a positive mood,” Whitaker says. “When you are positive and grateful, you are able to handle difficult situations better.” Just look out for these stress relievers that actually backfire.

For a few minutes a day, practice being mindful—focusing only on what's going on in the present —whether it's during your workout or taking a break from your work. Try taking a short walk and instead of thinking about what's worrying you, pay attention to your senses—what you see, feel, hear, smell. This can make a huge difference in your emotional and physical well-being when done daily.
I wouldn’t personally recommend listening to delta wave frequencies for depression, so I’m not sure who advised you to do that? People with depression usually have a higher ratio of theta and delta wave activity, so I would normally recommend listening to high alpha wave and low beta wave frequencies, to help balance things. I have some 10Hz alpha tracks for serotonin release, which you can try for free on my YouTube channel here: I also recommend you give these SMR (low beta wave) tracks a try: I hope that helps.

A more extensive study of over 100 participants who were undergoing general anesthesia for a day procedure, reported a decrease in pre-operative anxiety. The participants in this study listened to 30 minutes of binaural beats before surgery, but the researchers noted that people experiencing high levels of pre-operative anxiety could listen to binaural beats for up to 1 hour before anesthesia to reduce levels of anxiety.
Isochronic tones are the newest technological advancement in the field of brainwave entrainment. Isochronic tones are regular beats of a single tone. In fact, an isochronic tone is a tone that is being turned on and off rapidly at regular intervals, creating sharp and distinctive pulses of sound. This effect called “Amplitude Entrainment” tends to excite the thalamus and causes the brain to generate the same brainwave frequency (“frequency following response”) as the tone. The thalamus, vital structure lying deep within the brain, has multiple important functions: it is involved in sensory and motor signal relay, and the regulation of consciousness and sleep. Therefore, the use of isochronic tones is a very effective way to induce a desired brainwave state.
Alpha: Alpha brainwave patterns are associated with a state of wakeful relaxation. Slower and lower in frequency (between 9-14 hertz), alpha waves are dominant when we’re calm and relaxed, but still alert. Alpha waves are associated with states of meditation (your yoga class probably puts you in an alpha state), and also with our ability to be creative.

Binaural beats are the playing of two sine waves of close, but not the same, frequency into different earpieces of a set of headphones. The "beat" is heard as the brain tries to process them as a distinct sound, while taking into account the constructive/destructive interference. It is said to migrate brain waves to be closer to that frequency, like a sort of biological resonance, which is true. Of course the same can be said for listening to relaxing music help you relax, up tempo music to help you feel energetic, etc...

♥ When I learned about Binaural beats and found out how you can influence your state of mind, I utilized them for most of my college studies. I play 16Hz Beta waves behind my favorite study music. I've been using them for 3 years now and they help me stay focused longer. Just make sure you have quality headphones that can reproduce the frequencies accurately. 2Hz does make a difference with an EQ.
Beta brainwaves are next highest in frequency after alpha waves, occurring at 13 to 30 hertz. Beta brainwaves are what we experience every day as we are awake and using our analytic mind. Beta brainwaves are needed for concentrating on mental tasks, and when they are present for too long of a time, they lead to stress, anxiety, and even paranoia. Most people do not have trouble achieving beta brainwaves and in fact suffer from spending too much time in beta brainwave patterns. However, those with attention deficit disorder (ADD) who have problems focusing their attention can benefit from learning how to achieve and remain in beta brainwave states for longer amounts of time.
This incredible app which you  not only has over 3 hours of meditations valued at $200, the technology utilized is unlike anything else on the marketplace. The heartbeat synchronization augmentation gives you a completely immersive experiencing, tuning in to your body’s natural rhythms. It gives you the best binaural music on the market. Fully customizable, you can base your meditation on your mood, goals and timeframe. This is the perfect app for a deep, introspective experience.
This is probably the most popular choice of frequency. The theta state is a state of tremendous stress relief. The benefits associated with theta level relaxation include improved concentration, reduced hyperactivity and improved memory. While in a state of theta relaxation, one’s blood pressure, breathing and heart rate all slow to a much more restful and healthy level that promotes natural healing. During theta relaxation one may also experience vivid flashes of mental imagery as the mind opens to memories or subconscious information that is not available to the conscious mind during the normal waking state. The theta state is a very deep state of relaxation that is excellent for deep hypnosis and mental programming.
Sound and light are the most popular methods to entrain the mind, yet there are a few other options in our toolbox. Using vibrational energy from sources such as magnets and electricity has been proven to help overcome addictions, depression, and even treat neurological disorders such as Parkinson’s. In this section, we cover these alternative forms of brainwave entrainment.
With its focus on full, cleansing breaths, deep breathing is a simple yet powerful relaxation technique. It’s easy to learn, can be practiced almost anywhere, and provides a quick way to get your stress levels in check. Deep breathing is the cornerstone of many other relaxation practices, too, and can be combined with other relaxing elements such as aromatherapy and music. While apps and audio downloads can guide you through the process, all you really need is a few minutes and a place to stretch out.
But the question is: Does it have a special effect on the brain? A lot of people think so. The basic claim being made for binaural beats is "resonant entrainment". Entrainment, in physics, is when two systems which oscillate at different frequencies independently are brought together, they synchronize with one another, at whatever the combined system's resonant frequency is. Examples of entrainment occur in animals in nature; for example the chirping of crickets or the croaking of frogs. Synchronization of menstrual cycles in women is another example. Even people coming together and dancing with one another is a type of entrainment. The basic claim for binaural beats is that the perceived low-frequency beat will entrain your brain wave pattern, thus forcing your brain into some desired state.
Your brain operates at certain levels of activity – the normal waking, active Beta, the meditative Alpha, the asleep-and-dreaming or deep meditative Theta, and the deep sleep/unconscious Delta. Beta is characterized by one thing we all want to get away from – stress.But that brainwave state has its place. It’s the action mode, and that’s the way it should be! If we’re not alert when we’re awake, bad things can happen, right?