Brainwave Entrainment Frequencies
Binaural Beat Audio Programs
Brainwave Entrainment DVDs
Brainwave Entrainment Software
There are many meditation methods and meditation aids. One type of meditation uses technological aids to promote a deeper state of meditation, and specific brain wave frequences.
There are in a general sense three main types of brainwave entrainment technologies available today. These are:
- Binaural Beats
- Monaural Beats
- Isochronic Tones
Binaural beats are the most commonly used. Discovered in 1839, these are specific sound frequencies, a different one played in each ear (the carrier frequencies), the brain 'hearing' the difference (subtracting one frequency from the other, e.g. 20 Hz - 15 Hz = 5 Hz). Headphones are therefore required (preferably high quality headphones with great frequency reproduction). A less ideal alternative is to sit in between a set of stereospeakers, one ear facing each speaker, with the speakers at ear height preferably (less conducive to headaches and producing a harmful magnetic field). Some people get headaches when wearing headphones. This third beat or 'binaural beat' is said to entrain a specific brain wave corresponding to that frequency. One does not actually hear this binaural beat per se, but only the carrier frequencies. The brain however detects it. The effect is not instantaneous as the brain has to process the sounds in order to latch onto the binaural beat. Binaural beats are not the most effective for entrainment, but they are practical, and can be used to produce a variety of low target frequencies that are not possible with other methods. Binaural beats also have the added benefit of engaging both ears and both halves of the brain, producing a degree of brainwave synchronisation between the two hemispheres of the brain. Binaural beats, working on the basis of the difference between two frequencies, are not best suited to entrain high brainwave frequencies, such as HyperGamma (100Hz) or Lamba (200Hz) as the difference is too great.
Monaural BeatsSource: DPic http://en.wikipedia.org/wiki/Monaural_beats
Monaural beats are similar to binaural beats, except that the interference pattern is heard outside of the brain rather than inside it. This is achieved by playing both frequencies in each speaker, rather than a dedicated frequency in each speaker. Thus each speaker pumps out two frequencies, resulting in a sine wave pulse over the top of the output frequencies. If one listens to binaural beats on a HiFi using external speakers, then even when one is sat in between the speakers, one will hear some degree of monaural interference pattern. One does not have to use headphones with monaural beats. Monaural beats may be more effective than binaural beats in brainwave entrainment but because there is no processing by the brain, the pulse being heard outside the brain/body, then it does not provide the brainwave synchronisation effect between left and right hemispheres. In a 1973 issue of Scientific American, Dr Gerald Oster noted that Monaural waves create a far greater entrainment effect than binaurals. The benefit of listening to monaural beats is that the body can absorb the sound (up to a certain depth), whereas binaural beats listened to only with headphones are only 'heard' by the brain.
Isochronic Tones are regular beats or pulses of sound of the same tone, with silence in between each pulse or beat. Similar to monaural beats, the beat is heard outside the brain, but it is not the result of an interference pattern between two different sounds. The same freuqency of tones is output in each speaker and headphones are not required. Isochronic tones are more pronounced than binaural or monaural beats, and as such produce arguably the strongest brainwave entrainment benefit. However, similarly to monaural beats, they provide no brain synchronisation benefit. Some people do not like isochronic tones because they can be tiring or distracting to listen to. This need not be the case. In some instances, the beats are disguised by ambient music, which may lessen the actual effect of the isochronic tones slightly. Also, by their very nature, they cannot produce very low frequencies, as the spacing between the tones/pulses is too long, i.e. they can only be used effectively over 4Hz. I am aware of pulsed brainwave entrainment CDs, e.g. by Jeffrey Thompson, that are able to stimulate brainwaves all the way down to Epsilon (0-0.5Hz), using some manner of pulsed tones, although I am unable to confirm whether they are monaural, isochronic or both.
Brainwave entrainment audio designed for open air listening can incorporate both Isochronic Tones and Monaural Beats. Some packages use all three, and can be alternately listened to with external speakers and headphones (every other session), one benefitting from the isochronic and monaural beats in the former scenario and the binaural beats in the latter scenario.
Brainwave Entrainment Frequencies
The brain waves that are targetted for entrainment are usually Alpha, Theta and Delta. These are present in the brain, but often very faintly and in only certain isolated pockets of the brain, so the idea is to induce a specific brain wave more strongly into the brain. This may well result in increased blood flow in the brain, and with regular entrainment, the brain is said to recall these frequencies more easily and more strongly, with improved synchronisation between hemispheres, as it is supposed to do/can be trained to do/can achieve in ideal circumstances. The brain does not merely produce one type of brainwave at any one time but, a multitude of brainwave types in different parts of the brain. Entrainment is the practice of strengthening each type of brainwave frequency.
- Gamma (40Hz+) - burst of insight and high-level information processing
- Beta (13-40Hz) - heightened sense of alertness and focussed concentration
- Alpha (8-12Hz) - relaxed mental awareness, reflection, visualisation & creativity - Serotonin production.
- Theta (4-8Hz) - stress relief, deep relaxation, meditation, light sleep & dreaming
- Delta (0.5-4Hz) - deep dreamless sleep, healing and rejuvenation - Human Growth Hormone and natural opiate release.
Some brainwave frequencies are very hard to entrain, for example, anything below 2 Hz (i.e. low Delta and Epsilon (0-0.5Hz)) and in the Gamma range or above (HyperGamma (100-200Hz) or Lambda (200Hz)), although listening to them may still have beneficial effects on the body or interesting temporary effects in terms of altered states of consciousness. Gamma and above brainwave states are said to be useful for healing, feeeling compassion and personal transformation and breakthroughs. Epsilon is useful for deep relaxation, stillness, calming of the body and physical healing. Most entrainment is focussed on light Delta through to Alpha, and sometimes Beta as well.
The Schumann Resonance is 7.83Hz. This is sometimes called the 'Earth Frequency' as it is the frequency produced when light travels around the globe and reaches its original starting point (i.e. 7.83 compete circles of the earth in one second). Some repute that entraining the brain on this frequency can help to protect the body from the effects of Electromagnetic Smog, or rather restore the natural background frequencies of the earth that may be overriden by electrical and electronic devices and fields. Audio products that use the Schumann Frequency include The Holographic Mind's Deep Meditation and Into the Light CDs, and also Project Meditation's Lifeflow CD 7. Of course it is possible to create a binaural/monaural/isochronic track yourself using binaural beat generation software. The same frequency is used in Philip Stein watches and wristbands, approaching this from a different angle. To what extent this is true, I cannot say, but the brain does seem to benefit from the frequency which is high Theta, close to Alpha; and indeed from Philip Stein products (if it is what the body requires).
Gamma,Beta and Alpha binaural beats can be listened to whilst performing tasks, but Theta and Delta binaural beats should only be listened to whilst relaxing, reclining, lying down or meditating. Alpha can also be used for meditation or breathing exercises. Some CD programmes state what frequencies they target, which is useful whereas others do not. I have found Delta wave entrainment before bed useful to assist in falling asleep, and Alpha and particularly Theta wave entrainment for relaxation, stress relief and meditation. Delta meditation can also be helpful to rest, if one is deficient in sleep, even if one does not actually fall asleep. The more one entrains these frequencies, the more the brain will be effective in achieving them itself, i.e. in the case of Delta, inducing dreamless, restful sleep at night, which is often lacking in people with certain environment illnesses or suffering from fatigue. Also if one is regularly entraining Theta and Delta in the evenings, then one may be satiating some of the brain's requirements for Delta and Theta mind states, providing a sort of rejuvenating nap or rest, so that it requires less deep sleep and REM sleep during the night, meaning that one may well wake up feeling that one has got enough Delta and Theta sleep - as opposed to waking up feeling very tired (usually the result of insufficient Delta and REM sleep and too much shallow sleep in each sleep cycle one has).
In general, it is most helpful to use Delta wave binaural beats before going to bed in the evening, rather than during the day, as otherwise it may disrupt one's normal Circadian Rhythm (when the brain is trying to move away from Delta waves and produce other wave states). It may depend on whether you nap during the day and exactly what your cycle is like. Similarly, using Alpha or worse still Beta wave entrainment last thing at night may result in one feeling too awake and disrupting the Circadian Rhythm also.
Exposure to light or watching television is noted to promote alpha wave release (assuming the subject is relaxing!), the latter occurring because of the light emission. Television is of course not the recommended means of stimulating alpha waves but it can work. Other means of promoting alpha wave production include the precursors to Serotonin production and GABA production. And herbs containing some of these precursors or compounds that stimulate their production.
Measurements using EEG machines on Buddhist monks have shown a variety of different frequencies of brainwaves that appear during deep meditation, but predominantly alpha and theta waves. It has been noted that those monks participating in special types of meditation, to slow down the heart rate and to go into states of slow bodily function, for special religious purposes, use a combination of epsilon (lower Delta, specifically in the range 0-0.5Hz) and hyper-Gamma (100-200Hz) and lambda (200Hz). These are the lowest and highest frequency brainwaves, and the hyper-gamma and lambda waves seem to ride on the epsilon waves. Both are said to represent similar states of consciousness. Exploring such binaural beat programmes is probably best suited to those who have been entraining the four main frequencies for some time.
It is said that the actual volume of the carrier frequencies is not important, as the brain will detect them as long as they are at least faintly audible. Some binaural beats programmes have binaural beats in the foreground, and others have them in the background, behind ambient sounds or music, and cannot be noticed (which is much less annoying!). Some programmes use the actual music or sounds as the carrier frequencies, rather than a tone generator, and play the same sound/music at different frequencies in each ear (or parts of it in this way) to generate the binaural beat. They may also use phasing of the music/sounds to create a pulsing effect which may also correspond to the desired frequency (although this is technically not a binaural beat), and often 'swishing' the sound from one ear piece to the other.
Binaural Beat Audio Programs
Brain entrainment CD programmes tend to be extremely expensive for what they are, if you look at the total number of CDs and total price paid. Most brain entrainment programmes claim to require a period of adjustment, prior to listening to all tracks or going to the next 'level' CD. For programmes with multiple tracks, it is typically claimed to require 5 to 10 consecutive days of listening to the first track before proceeding to the second. Multi-level programmes may claim to require the user to stay on one level for 100 days before progressing to the next level. A next 'level' need not imply more advanced or better but is just a different frequency or set of frequencies, and the logic is likely just getting more benefit by focussing on one at a time.
Some argue that level-based programmes hold the user back unnecessarily, wheresas others swear they are the best method of progressing with brain wave entrainment. Advancing too soon may it is claimed result in headaches, as the brain is 'overloaded', i.e. more advanced entrainment is not effective. Part of this 'headache' sensation some claim to be overstraining one's nervous system. But if a real phenomenon, perhaps part of it is on account of increased blood circulation to areas not used to it, and possibly increased liberation of toxins from the brain cells. A number of manufacturers simply sell various different CDs or downloads, each with a slightly different remit, and it is up to the user to choose when to listen to them, e.g. time of day or mood.
On CDs with multiple tracks, if one is quite used to the programme, and wishes for a longer session or more intensive session, one may elect to play the last track twice for example. The order and sequence of tracks varies from CD to CD:
- Insight by Immrama Institute (now discontinued) - contains 3 tracks, and starts off with 24 minute Delta track. The second track is an Theta track, and third track is an Alpha track. In other words, the frequencies become higher as the CD progresses. Was available in rain or sea shore versions. Insight is a more traditional binaural beat programme and uses layering, but requires the use of headphones. Of course one can position oneself in between a pair of stereo speakers.
- Brainwave Suite by Jeffrey Thompson - the Alpha CD for example, the first 21 minute track is light to mid alpha (higher frequency, closer to beta?) and the second 21 minute track is mid to deep alpha (lower frequency, closer to theta?). After 'warming up' with the first track, the brain is claimed to be ready to listen to the second track and the deeper alpha waves. This if one elects to play the second track twice, and does not experience any adverse effects or headaches when doing so, then one may work on entraining deeper alpha frequencies. Dr Jeffrey Thompson's Brainwave Suite, and indeed his other audio programmes, can be listened to without headphones, so likely use isochronic tones in addition to binaural beats. Brainwave Suite is said to incorporate phase modulation, acoustic pacing primordial sounds and 3D recording and have been clinically proven. Whether this is better than some of the binaural beats CDs on the market is another question entirely and I have not formulated an opinion on this at this time. However, for those concerned with the health implications of wearing headphones, in terms of EM smog, then playing Thompson's programmes using stereo speakers is probably a better option. The music is rather cheesy and depressing arguably.
Individuals who are generally healthy report far more impressive results in the short term with binaural beats usage, compared with those with Chronic Fatigue Syndrome or related conditions. A friend of mine reported amazing results from using a few different programmes. When I tried these myself I was slightly disappointed as the results were 'slight' but was not really that surprised. This is probably because of the neurotransmitter imbalances (less calming neurotransmitters such as serotonin or GABA for example) in those individuals with neurological conditions, who require more entrainment in order to mimmick those of normal and healthy individuals. However, this is not to say that such individuals should not bother with binaural beats. Quite the opposite, they probably need to commit much more to such a programme, in order to get the various brain centres working properly again and to improve blood circulation in the brain generally. I have noticed that better results seems to come with increased durations, i.e. selecting a longer programme or repeating tracks (probably the latter tracks on multi-track CDs or whichever corresponds to the frequency that one wishes to focus on entraining). In this way, a person with neurological impairment of various kinds may experience 'similar' results to someone who is healthy but working the binaural beats CD much longer per session. This is something you will have to experiment with yourself to find how much is required and what the optimal listening time per programme is, of course building up to it with time over several sessions (or a headache may ensue).
Most brainwave entrainment CDs utilise multiple frequencies per session. However, a few products utilise only one frequency per session, claiming that it produces more effective brainwave entrainment results. An example of such a product is Project Meditation's 10 level LifeFlow programme, which also uses all 3 types of brainwave entrainment technology.
It is said that more brainwave entrainment occurs when one is sitting upright, e.g. on a chair or in a meditative posture, than when one is lieing down on one's back. The neurological system is more active when in an awake but relaxed meditate posture. I have tried various types of posture and has found less brainwave entrainment seems to occur when lieing on one's back. If one is sat upright, when combined with deep, diaphragm breathing, this seems to produce the best results. Diaphragm breathing is reputed to encourage more alpha waves in the brain.
Binaural beats programmes can be broadly classified into those with ambient sound/music only and those with ambient music or sound that also also include affirmations, subliminal messages and/or guided meditation. I personally did not want to hear a person's voice on the CD. One can purchase self-hypnosis CDs or downloads for that purpose as well, which may be equally or more effective, and only use them occasionally when one is in the mood.
Consider with repeated listens, certain types of audio may drive you nuts after a time, even if it sounds pleasing at first listen. Many companies do not employ talent ambient artists and create their own music or synthesised effects. Jeffrey Thompson CDs are in my opinion good but the Alpha CD sounds so cheesy, I cannot bring myself to listen to it. The Theta and Delta CDs are not as bad but still are far from enjoyable, but at least it is continuously changing. Lifeflow 2.0 uses a loop and whilst it sounds inoffensive and more background sound type effects, it can get wearing over the full 40 or 60 minutes, especially with repeated listens. Most of the 10 CDs are quite pleasing to listen to for the duration, whereas 2 of the levels were rather grating, one being thunder sound repeating over which made me feel anxious at the time (likely not so much now), and another just had an annoying chiming sound. One could argue that looping might help achieve a trance-like state if the audio is agreeable or inoffensive. Some audio CDs are pure tones, perhaps made with a tone generator software programme mixed in with some ambient sound effects in the background. Perfect Meditation is an expensive 13 level programme, and I only bought the first level, however the sound is in the form of chanting Tibetan Monks and Gongs, which is a nice touch. It may be better to opt for natural sounds with a least a long enough sample duration not to notice looping. Whilst most programmes recommend daily listens of the same CD, it may suit you better to play a different CD each time.
If you buy physical CD media, it is a good idea to rip a back up copy onto your computer as with repeated listens, especially daily, the CD will become heavily scratched and may become unplayable for a couple of years, and just because you have purchased it once and have a licence does not mean the supplier will offer you a replacement for free or even at a discount.
If you decide to convert your binaural beats audio CDs to your mobile phone or mp3 player (to listen to whilst on a train or on the beach, if you do not have a portable CD player), it is best to convert them without any loss, e.g. to WAV or FLAC format, as mp3 format may result in losses in the binaural beat production which may render the audio tracks slightly less effective. The less loss the better, and best still no loss at all.
There are many products on the market, and many make claims to be the best, however, I have trawled through numerous reviews and found that no one product performs consistently better than any other, or at least not all the time, with all subjects, and it depends on the individual as to which programme might suit one best (at a particular point in time perhaps also). It is perhaps best to experiment with a few different programmes until you find what works best for you. Some manufacturers and indeed users make various 'new age' claims about the effect of certain products, and one may wish to take these with a pinch of salt if one is not that way inclined, or until one has directly experienced them oneself. If nothing else, the marketing speak should not detract from the scientifically proven effectiveness and validity of these techniques.
Multi-level audio programmes have an ordered and sequential programme for frequency entrainment, and may well cover a wide variety of frequencies in each level. Products such as Brainwave Suite and Insight include separate CDs/tracks for each type of brain wave, and so allow the user to choose what type of brainwave to entrain. Whilst many users like to use Delta prior to going to sleep, one can also choose Alpha or Theta to entrain at other times. I have found that regular daily entrainment of Alpha, without doing any Theta entrainment, gradually contributed to insomnia, which was rectified when focussing more on Theta (Delta being run every day prior to going to bed in any case). When you can choose yourself, one has to exercise self-discipline to choose what is right for oneself and to balance it out properly if necessary. Multi-level programmes are supposed to do this 'thinking' for you. However this is no one size fits all, and some people get on better with some programmes than others, and clearly entraining certain types of brainwave frequency maybe beneficial for one person and detrimental to another, depending on brain chemistry and neuro-endocrine system issues.
Binaural beats based products are said to accelerate the rate at which meditation practice progresses, and also to boost one's hormone levels and endocrine system, and result in better emotional balance. Some programmes claim to be geared more towards entertainment, and out of body type experiences, but whether they actually do what they claim is another matter, and I've yet to have experienced 'out of body experiences' by meditating to such a CD. Pure entrainment is a much more worthwhile goal initially. I have to date tried Perfect Meditation, Insight, Focus, Dr Jeffrey Thompson's Brainwave Suite, Dr Jeffrey Thompson's Epsilon CD, Ultra Meditation's (MindTek) X-Series, Binaural Beats' Chakra Cleansing and Power Siesta, and The Holographic Mind's Into the Light, as well as the Procyon AVS mind machine, and has been reasonably happy with all of them, with the exception of the Binaural Beats' CDs and the Procyon (described below) which are merely 'OK'. I have been particularly impressed with the Brainwave Suite series and Epsilon CD, which have yielded phenomenal results and states of wellbeing in conjunction with either Standing Qi Gong or meditation whilst having an Epsom Salts foot bath.
Please note that whilst binaural beat brainwave entrainment and brain synchronisation can be a very powerful meditation, personal development and entertainment tool, it should be used in conjunction with a full Neuro Linguistic Programming (NLP), Neuro-Associative Conditioning (NAC) or other personal development programme that requires reflection, analysis and/or changing of mental associations, retraining neuro-responses and stimulus interpretation, rather than just using brainwave entrainment as a psychological fix for your psychological problems.
Binaural beats with ambient sound/music
Below are a few selected manufacturers of binaural beats CDs.
- Center for Neuroacoustic Research, founded by Dr Jeffrey D. Thompson, D.C.
- Perfect Meditation
- LifeFlow Meditation 2.0 by Project Meditation
- Optamind Meditation
Offer 3 products Optamind Awakening Meditation (Beta, Alpha, Theta & Delta), Gamma Meditation and Study Buddy. Each is contained on one CD and there are no additional levels.
- Quantum Mind Power Program with TMM (The Morry Method) by Morry Zelcovitch
supply individual CDs with tones heavy in the foreground
A range of binaural beat CDs by Monroe Products, incorporating binaural beats over musical or sound backgrounds (most interesting sounding of above).
- Brain Evolution System
Binaural beats including Affirmations/Subliminal Messages/Guided Meditation
- Holosync by Centerpointe Research Institute
Awakening Prologue is the first part of the programme, with subsequent parts using your actual voice recordings to create custom affirmation in subsequent CDs for you. 13 levels in total.
Self-hypnosis CDs to trigger meditative states using sounds that correspond to various brain wave frequencies.
A variety of guided meditations and pure sound mp3s for a variety of goals. One includes the Extra Energy mp3 which is based on an 18Hz frequency, which was trialled (the frequency not Extra Energy) on CFS sufferers in 1998.
Mind Machines, also known as Brain Machines or AVS, combine binaural beats with flashing LEDs that flash at the same frequency as the 'binaural beat' (i.e. the difference between the carrier frequencies), to further assist in entrainment. The LEDs are housed inside pair of goggles or sunglasses which are plugged into the AVS unit and when in use the eyelids must be closed. In this context, the brightness of the LEDs is proportionate to the amount of entrainment that occurs, but of course one does not want to set the LEDs too bright or it may irritate the eyes or cause damage to the retinas.
It may take one a week or two to get used to the LEDs and one may find oneself gradually increasing the brightness of the LEDs with time. It is helpful to try to relax the eyes. Some may wish to focus the eyes on the flashing lights (from behind the eyelids) and others may wish to relax the eyes and go to long distance focus.
Blue light is most suitable for alert relaxation (and can help to arouse one in the mornings and reduce melatonin production), whereas red light tends to be more stimulating, energising and even stressful (perhaps working more on the adrenal hormone and neurotransmitter production, particularly in conjunction with Beta frequencies). Theta and Delta programmes are therefore best used with a predominantly blue or green light/LEDs. As bright lights, particularly at the blue end of the visible spectrum, are known to reduce melatonin production, it may be well not to set the brightness of the LEDs too high if using a Theta or Delta programme in the late evening or immediately before going to bed. However, in most cases, because of the audio and visual brainwave entrainment, the overriding effect is that of sleep or deep relaxation induction, and perhaps increased melatonin production (in the case of Delta programmes), rather than decreased.
On a low setting, less light probably enters the eye than it would with the eyes closed in daylight or standing near a light source. One may alternatively elect to use a binaural beat CD or mind machine with goggles switched off/unplugged for such late evening/night applications. Try and experiment. It perhaps depends on the individual to some extent.
Mind machines that provide both binaural beats and flashing LEDs are of course dearer than simply CDs, but usually contain a number of different programmes, so are more comparable to an entire programme of CDs. The quality of programmes in mind machines is debatable compared with some of the more cutting edge audio programmes, although it depends on the unit. Some units may allow the user to make custom programmes. AVS devices' range of possible frequencies may be limited compared with audio CDs, mainly at the upper end. e.g. the Procyon AVS is only capable of frequencies between 0.1 Hz and 75 Hz and so is not able to produce frequencies in the higher end of Gamma, nor Hypergamma or Lambda.
One should bear in mind that the brain does not generally respond to very low frequency binaural beats according to some (e.g. less than 2Hz), and that mind machines are not really suited to anything less than around 2Hz as the long space in between flashes becomes increasingly irritating the lower the frequency. Using a mind machine with audio only, or simply purchasing a low Delta or Epsilon CD Programme may be a better bet if one wants to entrain these low frequencies.
One thing one can say about mind machines is that they are likely to produce worse headaches in some people who are sensitive to electronic devices, particularly as they use LEDs immediately adjacent to the eye as well as headphones. Brainwave entrainment CDs can be used if one is sat between two speakers at a reasonable distance apart, particuarly if they utilise isochronic tones.
Another consideration is that mind machines, although supplied with headphones, are usually supplied with very cheap headphones, and it may be worth buying a high quality set of headphones. This is presumably to keep costs down. The market for AVS is quite limited and the devices are often made to a budget in China. Whilst the Procyon AVS I had was functional, the case and button action felt cheap. They are often bereft of features and expensive for what they are, compared with other portable electronics products for the mass market.
I spent 6 months using my Mind Place Procyon (an older model), after which time I noticed I was developing headaches with each usage (similar with headphones only usage), and proceeded to listen to brainwave entrainment audio on my stereo instead and sold my Procyon. Procyon Audio Visual Synthesizer (AVS) by MindPlace is a mind machine (incorporating binaural beats and LED goggles). The goggles have LEDs of 3 different colours, and each coloured LED has 255 different levels of brightness, so many colour combinations are possible. The device comes with 50 preset programmes. Frequencies possible: 0.1 - 75.0 Hz. Auxiliary input for external audio input to 'mix' with binaural beats. A (basic) PC interface only for customisable sessions (will work on a Mac if you have Parallels Virtual Machine or similar and a copy of Windows but requires configuration of the COM ports). Proteus is the cheaper version with red LED goggles only (probably not so suitable for evening use and deep relaxation use.) Mind Place have a support forum but I personally found it of limited use.
Brainwave Entrainment DVDs
An alternative to mind machines are brainwave entrainment DVDs or videos. These may well rely on isochronic or monaural tones more than binaural beats (depending on whether they are designed for use with headphones or not) and also utilised strobed flashes. Some mind machines produce a background hiss, which worsens when the batteries become low. This affects the Procyon in particular. This can be solved by using a pair of in line headphones or an in line volume control lead that plugs into the end of your headphones lead. Unfortunately this means having two sets of volume controls to contend with, one on the device and one on the headphones lead. The idea is to turn the device volume up to maximum and the headphones volume down to a low, comfortable setting.
Brainwave Entrainment Software
There are also binaural beat generation programs available, almost entirely for Windows, but of course they can be run on a Mac with the correct Virtual Machine software and a copy of Windows (if you can get it to work!). Some are sound only, i.e. for generating sound files that can be burnt to CD or otherwise, whereas others are designed to actual play binaural beats tracks in conjunction with a flashing strobe on the screen, synchronised. Some products allow the user to mix the binaural beats with music. One example is Neuro Programmer 2 (NP2) by the Transparent Corporation. However, in my opinion, music/ambient music professionally layered with binaural beats (as to be imperceptible), even though they can become slightly annoying when listening to the same track 50-100 times (!), are preferable to pulsing tones which are akin to a form of torture, even if mixed in with music (they would still be very annoying). However, it is clearly personal preference.