By Bruce Murison
Look back at our history, and you'll see it's full of sexual devices that predate the Romans. We wasted no time inventing the vibrator as soon as electricity became available to the masses in the 1800s.
Compressed air, vacuums, steam, and wind-up springs have powered orgasm-inducing contraptions, but electricity has come out on top. Not much has changed from the original vibrator design. Plug-in and battery-operated vibrators still work using the same principles from 135 years ago: Most sex toys spin an off-center weight to create vibration.
Still, there are several other types of electricity-driven systems that produce pleasing sensations.
Electromagnets excited with 120 VAC vibrate flexible steel to produce a linear, up-and-down motion. These "coil-operated" massagers all buzz with that familiar 60-cycle hum. The alternating current in our outlets happens to have a frequency of 60 hertz (cycles per second), the sweet spot for a gentle, low-speed orgasm.
A plug-in electromagnetic massager is inexpensive to manufacture because it's just a wire wrapped around a piece of steel; no electronics are required to produce motion directly from electricity. The drawback of coil-operated massagers, the type found in drugstores, is that most don't have variable speed and they quickly lose power under load.
These devices are never battery-operated because they are very inefficient and consume huge amounts of electricity. Some early-model clitoral stimulators were five pounds of steel and got so hot that users commonly held them with oven mitts. We've made some progress since then.
Also running at 60 hertz are the oscillating stimulators that move back and forth like a toothbrush. The high and low settings don't actually change the vibration "speed," which remains constant at 60 hertz, or 3600 revolutions per minute. The low setting has less travel, or fewer degrees of rotation, and therefore gives less vibration energy to the user.
Oscillating vibrators can be very powerful, but the theory is that their twisting motion is less jarring and causes less impact. Less impact means more power can get closer to the clitoris without being overwhelming.
I am not aware of any data comparing linear, rotational, and oscillating motion for pleasure ratings. Each of the three types of devices would have to have the same shape, texture, frequency and power in order to compare how they feel. In my experience, what matters most are the frequency and power of the vibration, not its direction.
An oscillator conceivably could have a smoother vibration than a coil-operated massager, but I don't see how anything can top the perfect sine-wave vibration most vibes produce by spinning an off-center weight in the grand sex-toy tradition.
Electric motor-driven massagers are much more powerful and efficient than their coil-operated cousins. Motors can be used to drive a crankshaft and produce linear motion with variable speed and lots of power. Massagers driven by motors shake large muscles slowly with huge amounts of power. The massage head moves up and down, and the reciprocal motion often is as much as a quarter of an inch.
Power is most influenced by the amplitude of the vibration. Think of as a vibration as a sine wave. The height of the wave is the power and the length of the wave is the speed, or frequency. A faster or higher frequency has a shorter wavelength.
A small vibe does not have much power because it does not move much. It may have a high speed of 7,000 rpm, but it has low power. If you put a vibe on a table, it will buzz around while the vibrations bounce off the hard table surface.
If you place a high-end sports massager face-down on a table, set it to a low speed of 600 rpm and turn it on, it immediately will leap into the air and smack you upside your head. It has a lot of movement and may be powerful enough to bruise an unsuspecting victim.
Most stimulating vibrators use electric motors to spin an off-center weight and produce a 360- degree circular vibration pattern.
The main advantage of the off-center-weight method is that it is an easy, efficient way to create smooth vibration patterns. But it has a downside: The fewer revolutions per minute, the less power the vibrator provides. Ideally, you want the same or more power at a lower rpm level.
The slower the weight spins, the less g-force it creates. The larger the weight's diameter and mass are, the more g-force, or power, is created for a given number of revolutions per minute. Your typical vibrator motor is efficient enough to produce strong stimulation, even though it runs on batteries, so most don't need a 120 VAC cord.
There are two basic types of DC electric motors used for vibes: coreless and cored.
Coreless motors are more expensive, produce less power for their size and get hotter, but they can last thousands of hours. Cored motors put out reasonable power, are less expensive and a few hundred hours of life can be expected from a quality toy. On the other hand, many coreless motors have life expectancies that fall short of 100 hours. You get what you pay for, since the best cored and coreless motors contain gold and other exotic metals.
Modern technology has brought us small bullets and micro-vibes smaller than a quarter of an inch across. Small-diameter vibrators tend to have higher rpm levels and very little power. Larger vibes certainly can provide enough power across a large frequency range, and medium motors about half an inch across are a good compromise. In the end, off-center-weight vibrators have completely dominated the toy market.
The ideal vibration tends to be different for each individual, but there seems to be some agreement that 3,300 rpm and 5,000 rpm are ideal for gentle and climactic orgasms, respectively. A reasonable portion of the population likes up to about 7,000 rpm under the right conditions.
The desired duration of stimulation seems to reduce as the rpm count goes up. Lower rpm levels are easier to endure. Going above 9,000 rpm leaves many numb after only a few minutes.
Because changing the frequency-power combination is pleasing, toys with five or more modes are popular. These toys ramp their speeds up and down in various repeating cycles. People tend to enjoy small amounts of fancy computer-driven patterns, but when it comes to having an orgasm, many appear to like a fairly constant, non-distracting vibration.
Although technological advances have made it possible to create smaller and more powerful motors cheaply, the laws of physics limit us just as they did the 19th-century electrical engineer whose work led to the first vibrator. That's fine: It looks like he got it right.
Bruce Murison, president of Standard Innovation Corp., has 25 years of experience in applications-engineering research and development with a focus on cutting-edge electromechanical products. He has invented a line of adult toys that includes the We-Vibe, which combines patent-pending concepts and space-age technology.
