glossary
07

Glossary

A working reference of frequency, resonance, and vibration terminology used across Frequency theory, research, and hardware.

Categories
01Fundamentals02Resonance & Vibration03Acoustics & Sound04Electromagnetic Spectrum05Biological & Bioresonance06Signal Theory & Analysis
01

Fundamentals

Base vocabulary for describing any oscillating signal — the units, shapes, and measurements used throughout the site.

Frequency
Cycles per second, measured in Hertz (Hz).
The number of complete oscillations of a wave that occur in one second. 1 Hz equals one cycle per second; 1 kHz equals one thousand cycles per second. Frequency is the reciprocal of the period (f = 1 / T).
Wavelength
Spatial length of one full cycle.
The physical distance a wave travels during one complete oscillation. For a sound wave in air at 20 °C, λ = 343 m/s ÷ f. Higher frequencies produce shorter wavelengths.
Amplitude
Peak magnitude of the oscillation.
The maximum displacement from the equilibrium position. In acoustics amplitude relates to perceived loudness; in electromagnetism it relates to field strength.
Phase
Position within a cycle at time t.
Expressed in degrees or radians. Two waves of the same frequency are in phase (0°) or out of phase (180°). Phase relationships determine constructive vs. destructive interference.
Waveform
The shape of the oscillation over time.
Common shapes include sine, square, triangle, and sawtooth. Any complex waveform can be decomposed into a sum of sines via Fourier analysis.
Harmonic
Integer multiple of a fundamental frequency.
The 2nd harmonic of 100 Hz is 200 Hz. Harmonics define the timbre of an instrument, voice, or resonating system.
02

Resonance & Vibration

Terms describing how systems store, exchange, and amplify vibrational energy at preferred frequencies.

Resonance
Amplification at a system's natural frequency.
When a driving oscillation matches a system's natural frequency, energy transfer becomes maximally efficient and amplitude grows dramatically. The basis for musical instruments, MRI, and Frequency's hardware.
Natural Frequency
The frequency a system oscillates at freely.
Determined by mass, stiffness, and geometry. A tuning fork, a wine glass, and a bridge each have distinctive natural frequencies.
Standing Wave
Stationary interference pattern.
Formed when two waves of equal frequency travel in opposite directions and superpose, creating fixed nodes (no motion) and antinodes (maximum motion).
Chladni Pattern
Visible node geometry on a vibrating plate.
Sand placed on a plate driven at a resonant frequency collects along the nodal lines, making the standing-wave geometry visible. Named after Ernst Chladni (1787).
Q Factor
Sharpness of a resonance peak.
Quality factor: the ratio of energy stored to energy dissipated per cycle. High-Q resonators are narrowly tuned and ring for a long time; low-Q resonators are broad and damped.
Entrainment
Synchronization of coupled oscillators.
Two oscillators exchanging energy tend to lock into a shared frequency or phase relationship. Observed in pendulum clocks, firefly flashes, and neural rhythms.
03

Acoustics & Sound

Vocabulary specific to pressure waves in air, water, and solids — including audibility ranges relevant to our sonic hardware.

Infrasound
Below 20 Hz — below human hearing.
Produced by weather, earthquakes, and large machinery. Can be felt as pressure or vibration even when not heard.
Audible Range
20 Hz – 20 kHz for young adult humans.
The typical range of frequencies perceived by the human ear. Upper limit decreases with age.
Ultrasound
Above 20 kHz — above human hearing.
Used in medical imaging, cleaning, distance sensing, and cellular stimulation. The Sonic Wand S1 operates in this range.
Decibel (dB)
Logarithmic ratio of two intensities.
A tenfold power increase equals +10 dB. Sound pressure level (SPL) is referenced to 20 μPa in air.
Cymatics
The study of visible sound.
Coined by Hans Jenny (1967). The discipline of making sound and vibration visible in media such as water, sand, or ferrofluid.
04

Electromagnetic Spectrum

Frequencies of light and radio, from the extremely-low-frequency Schumann band up through visible light.

ELF
Extremely Low Frequency: 3 – 30 Hz.
Includes the Schumann resonances and biological brainwave bands. Penetrates deep into water and rock.
Schumann Resonance
Earth-ionosphere cavity resonance, ~7.83 Hz.
The fundamental resonant frequency of the space between Earth's surface and the ionosphere, excited by global lightning activity. Higher modes at 14.3, 20.8, 27.3, and 33.8 Hz.
Radio Frequency (RF)
3 kHz – 300 GHz electromagnetic waves.
Used for broadcasting, wireless communication, and radar. Subdivided into VLF, LF, MF, HF, VHF, UHF, SHF, and EHF.
Terahertz
10¹² Hz — between microwaves and infrared.
Non-ionizing radiation increasingly used in imaging and spectroscopy. Many molecular vibrations occur in this range.
Visible Light
~430 – 770 THz (700 – 380 nm).
The narrow band of electromagnetic radiation detectable by the human eye.
05

Biological & Bioresonance

Frequencies observed in living systems and terms used in bioresonance research contexts.

Brainwave Bands
Delta, Theta, Alpha, Beta, Gamma.
Delta (0.5–4 Hz, deep sleep), Theta (4–8 Hz, meditation), Alpha (8–13 Hz, relaxed wakefulness), Beta (13–30 Hz, active thought), Gamma (30–100 Hz, high-level processing).
Heart Rate Variability
Beat-to-beat variation, measured in ms.
A frequency-domain marker of autonomic nervous system balance. Coherence peaks appear around 0.1 Hz during paced breathing.
Solfeggio Frequencies
A set of tones cited in sound therapy.
A six-tone scale — 396, 417, 528, 639, 741, 852 Hz — popularised in modern sound-healing practice. Studied but not medically established.
Piezoelectric Effect in Tissue
Charge generated by mechanical stress.
Bone, collagen, and DNA exhibit weak piezoelectric behavior, allowing mechanical vibration to induce electrical signaling at the cellular level.
Bioresonance
Interaction of external oscillations with tissue.
The premise that biological structures have characteristic resonant frequencies which can be probed or influenced by matched external fields.
06

Signal Theory & Analysis

Mathematical tools used to decompose, measure, and shape signals in our lab work.

Fourier Transform
Decomposition of a signal into sinusoids.
Converts a time-domain waveform into its constituent frequency components. The Fast Fourier Transform (FFT) is the standard algorithmic implementation.
Spectrum
Distribution of amplitude across frequency.
A frequency-domain view of a signal. A pure sine has a single spectral line; noise fills the spectrum.
Bandwidth
Width of a frequency range.
The difference between the highest and lowest frequencies of interest, or the span across which a filter or resonator responds.
Nyquist Frequency
Half the sampling rate.
The maximum frequency that can be unambiguously represented by a discrete sampled signal. Above it, aliasing occurs.
Modulation
Varying a carrier by an information signal.
AM varies amplitude; FM varies frequency; PM varies phase. Foundational to broadcasting and to shaping therapeutic waveforms.