Some Resonance Basics

Resonance is a vibration caused by another vibration. Vibrations happen at virtually all conceivable frequencies, and in all energetic realms. Another way to think about it: resonance is the cyclic interaction between two entities.

The main elements of resonance are (1) source amplitude, (2) source frequency, (3) target damping, and (4) target tuning. I'll talk about a fifth element, intention, in a later post.

Power is the amplitude of the source vibration. In a sound context, it's how far the air moves in each cycle of the sound wave. While this has much to do with perceived loudness, it's not the same thing, since our perception of loudness depends on a combination of amplitude, pitch, and subjectivity. The energy contained in a source vibration is proportional to the square of the amplitude of the wave. So if you increase the amplitude by a factor of two, the energy increases by a factor of 4. In addition, if you have two soundwaves with the same amplitude, one at a higher pitch, the one with the higher pitch has more energy.

Source Frequency, again in the context of music, is pitch. More generally, it's the number of cycles per given unit of time of a given vibration. So our brain's Alpha wave frequencies range between 8 and 12 cycles per second, or Hz. The lowest A on the piano is 26 Hz. Pluto's orbital cycle is .004032 revolutions per Earth year (one orbit around the sun every 248 years).

So we have a source that is vibrating at given frequencies and amplitudes, creating energy. The amount of that energy depends on the amplitude and frequency of those vibrations. The extent to which we get resonance from that energy depends on the target.

Target Damping is the degree to which the target is free to vibrate in response to energy from the source. If the target is heavily damped, it will have a very small and undifferentiated reaction to the cyclic energy of the source. As damping decreases, the target vibrates more. When damping passes through zero and goes into the negative, it is energy that essentially amplifies the source. So a target can either reduce or increase the energy from the source.

Target Tuning is the degree to which the target can "hear" the vibrations of the source. In the simple case of a tuning fork tuned to A440, it will only resonate to the same source frequency of 440Hz (Actually, it will also resonate to certain lower frequencies, but more on that in a later post). Jonathan Goldman calls this "free" resonance. The soundboards and air columns of musical instruments, on the other hand, are designed to resonate at a variety of frequencies. Indeed, the quality of that resonance in musical instruments is the foundation of the quality of the instrument itself. Johathan Goldman calls this second type of resonance "forced" resonance, and it is by far the most common type of resonance that we encounter in our day-to-day lives.

So to summarize: Resonance is the cyclic interaction between two entities. The degree of resonance depends on the amplitude and frequency (energy) of the source, combined with the damping and tuning of the target. This definition applies to all frequencies, from the planetary to the super-atomic, and in all energy realms, from the gross to the subtle and causal.