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Text File | 1992-05-28 | 10KB | 171 lines

COMPARING LIGHT AND SOUND "MIND MACHINES"

On the surface of it, a light and sound mind machine sounds like a pretty
simple gadget, just a flashing light.  What could be so difficult about
building one, and why are they so expensive?  Actually, the best light and
sound mind machines have more features than just a blinking light.  Let's
start with the essential features.

PRECISION FREQUENCY CONTROL:  The single most important feature of a light
and sound mind machine is the ability to specify the precise frequency that
you desire.  At a bare minimum, you should be able to specify this to the
nearest half Hertz; accuracy to the nearest hundreth of a Hz is to be
preferred.  It should handling blinking down to at least 4.0 Hz, and
preferably down to 0.5 Hz.  It should handle blinking up to at least 18 Hz,
and preferably 25 Hz or more.

EVENLY LIGHTED FIELD:  The more light sources per eye, the better the
effect overall.  The original Synchro Energizer uses four bulbs per eye,
plus one for the "third eye" placed on the bridge of the nose.  The Mind
Gear Innervision PR-1 and PR-2 also have four LEDs or four bulbs per eye.
Several machines have three; some cheaper machines have only two. Having
only a single bulb or LED per eye is a warning sign that the machine is
almost certainly a piece of crap.  Look for a good brightness control, too.

FREQUENCY FOLLOWING RESPONSE (FFR):  These machines modify your brainwaves
by starting at you current dominant frequency and gradually transitioning
you to another frequency.  To do that, a light and sound mind machine must
have some kind of timer, and an ability to specify starting and ending
frequencies.

BASIC SOUND FEATURES:  To have a true light and sound mind machine, you
have to have some kind of tone generator pumping tones into a pair of
headphones.  The tones will beep for the entire time that the lights are
lit.  At bare minimum, the machine should produce comfortable simple beeps,
and give you control over the pitch and volume.  And it really ought to
generate binaural beat frequencies, where the difference in pitch between
the left and right speakers is equal to the beat frequency in Hz.

WARRANTY AND SERVICE:  Find out how long the warranty lasts, what it
covers, what escape clauses they give themselves, and what you have to pay
to get a covered repair.  (Watch out, or you'll end up having to pay
insured overnight international airfare both ways.)
    _____

The next tier of features are all very important, but not essential.  I can
imagine getting some use out of a machine that didn't have them.

GENTLE FADE OUT:  At the end of a timed session, the light intensity and
sound volume should fade out gradually.  This feels much better than being
dumped out abruptly.

BEAT FREQUENCY TRICKS:  You can do a lot more with a light and sound mind
machine if it can play seperate frequencies into seperate hemispheres of
your brain (left eye with right ear, then vice versa).  Interestingly,
small differences in frequency, 0.5 to 1.0 Hz, can make a big difference in
the quality of the visuals.  Also nice is the ability to set the left and
right hemisphere to the same frequency but 180 degrees out of phase; this
has the same entrainment effect but feels different.  (Switching from one
to the other and back during a session can help keep you attentive, and
keep your mind from drifting off of the frequency.)

BETTER AUDIO:  Look for the ability to plug in an external audio source and
have it mix with the audio beats.  This lets you use mind altering tapes,
like HPP, Paraliminal, or subliminal hypnosis tapes while running a mind
machine session.  Sound effects are nice, too, particularly the ability to
generate "pink noise" (gentle, pleasant static) and a simulated (or
digitized) heartbeat, but these are luxuries.

GOOD HEADPHONES:  Most units ship with dime-a-dozen terribly cheap stereo
headphones.  That's OK, you can replace them with better ones yourself. But
if one of the machines you're looking at offers much better headphones,
remember to figure that into the price of the cheaper one.

GANZFIELD EFFECT:  Some people like the ganzfield effect (continuously on,
lighted but blank field) for itself, as a meditation aid.  I hear rave
reviews about using it with sensory deprivation.  If you do intend to use
the ganzfield effect, then consider two other optional features. First of
all, audio sound effects like pink noise, a "wave generator," and/or a
heartbeat may add a great deal.  Secondly, consider getting a unit with
incandescent bulbs so you can use gel filters to change the color of the
lighted field.  (This is the only known reason to prefer white incandescent
bulbs to LEDs.)

LOTS OF USEFUL PREDEFINED SESSIONS:  It can save you some work if the unit
has a simple way of picking a predefined session off of a menu or list,
saving you the effort of remembering and specifying the target frequency
and duration (as well as any other effects; see below).  If a unit has
preprogrammed sessions, there should be at least one beta, several each for
different levels of alpha and theta, and at least one delta.  More variety
is better, of course.  It's also nicer if some of the preprogrammed
sessions can make more than one "ramp" from frequency to frequency.

PORTABILITY:  It turns out to be very handy to have a unit that you can
take with you.  You may not think so, but if you have a portable unit,
you'll find that you have more uses for it, as you take it places. How big
does that mean?  Unless the features were very, very outstanding or the
unit was being purchased to be installed in a permanent "mind spa", I
personally would avoid any unit that was bigger than a hardcover book or
weighed more than 3 pounds.  Smaller and lighter is better.  Different
people will have different limits, but you should set yours.  Also consider
the power source.  Units with built-in rechargeable batteries and built-in
chargers are the most convenient.  Anything that runs on batteries can be
run on rechargeable batteries, of course.  Units that have to plug into the
wall are less convenient.
    _____

The next tier of features are all true luxuries; things that can add to the
enjoyment of the experience of the flexibility of the unit, but you can get
a lot out of a unit that doesn't have them.  Look really hard at these
features only if you're outfitting a mind spa, or can afford to be a real
experimenter.

PULSE SHAPE AND WIDTH CONTROL:  Most machines use a 50% on, 50% off square
wave for light intensity and sound volume.  Some companies claim that at
low beat frequencies, a sine wave or triangular wave would be better. Also,
if you are using a square wave, the percentage of each cycle that the light
is lit can make a big difference in the visuals.  (This is the only known
reason, except maybe battery life, to prefer LEDs over incandescent bulbs.
Light bulbs can't go much below 40%, and some companies report best results
down around 15%.)

USER PROGRAMMABILITY:  The ability to progam your own sessions is very,
very nice, particularly since all of the research isn't in yet.  When
comparing programmability, don't just ask how many sessions you can
program.  Equally important, find out which variables can be programmed per
step, and what is the maximum number of steps per session.  It's worth
getting a copy of the manual (if possible) and looking at the user
interface, too, to figure out if YOU can program it.

PC COMPATIBILITY:  The ultimate in user programmability is to buy a light
and sound mind machine that plugs into your brand of computer, and lets you
program all the session parameters in a programming language that you
already speak.  (If, in fact, you own a personal computer and speak a
programming language.)  Of course, this completely eliminates the
possibility of portability, unless it's an external unit that can be
controlled via serial port, and plugged into a laptop.  (So far, none of
them are.)

COMPATIBILITY WITH ELECTRICAL STIMULATION:  Strictly speaking, ever since
the Light & Sound Turbocharger became available, all light and sound mind
machines are electro-stim capable.  But there are several units that
combine the a light and sound machine with an electro-stim machine.  If the
features that you want are there, the price may be right.

BIOFEEDBACK:  So far, none of the regular light and sound machines doubles
as a lucid dreaming reinforcement device, with their ability to detect REM
sleep.  They have enough hardware in common, though, that I have to think
that sooner or later one will.  In the meantime, though, both of AlphaLabs
units can be connected to an EEG that reads your dominant frequency and
adjusts the light frequencies to "lead" it gradually in the right
direction, which should make for much more accurate entrainment. Look for
other manufacturers to follow suit.

BRAND NAMES:  Synchro Energize, Comptronic Devices (makers of the DAVID
line), and InnerQuest have been building light and sound mind machines for
a long time.  (On the other hand, InnerQuest has recently built at least
one unit that doesn't meet the minimum specs above, so you can get burned.)
AlphaLabs (the Shaman and the DreamWave II) has been in the market for
almost as long.  If you buy a unit from one of those four companies, you
can have a pretty good idea that it'll be solidly built and will last. With
other companies, you might want to ask around, or wait until you see one,
or try to buy it from a distributor with a good return policy.


Ken Pedrotti
Rockwell Science Center