Online Tone & Frequency Generator
Synthesize pure acoustic frequencies from 20 Hz to 20,000 Hz. Test hearing limits, calibrate studio monitors, experience stereo binaural beats, and generate Solfeggio harmonics in real time.
Automated 15-second acoustic sweep to test your speaker tweeters and biological ear frequency limits.
🎧 Stereo Binaural Beats
Requires stereo headphones
Acoustic & Solfeggio Presets
📊Human Audio Frequency Spectrum & Solfeggio Harmonics Guide
Standard acoustic frequency divisions and their physical, physiological, and musical characteristics.
| Frequency Band | Hertz (Hz) Range | Auditory Perception | Typical Sound Sources |
|---|---|---|---|
| Sub-Bass | 20 Hz – 60 Hz | Felt more than heard; tactile deep vibrations and chest thumps. | Subwoofers, pipe organs, kick drum sub-boom. |
| Bass | 60 Hz – 250 Hz | Foundation of harmony, fullness, and rhythm weight. | Bass guitar, cello, lower male speech fundamentals. |
| Low-Midrange | 250 Hz – 500 Hz | Warmth and body; too much causes acoustic muddiness. | A4 Concert pitch (440 Hz), acoustic guitar resonance. |
| Midrange | 500 Hz – 2,000 Hz | Horn-like presence; area where human hearing is most sensitive. | Human speech intelligibility, telephone audio band. |
| Upper Midrange | 2 kHz – 6 kHz | Clarity and vocal attack; can cause harshness or ear fatigue. | Snare drum crack, speech consonants (s, t, k). |
| High Treble / Brilliance | 6 kHz – 20 kHz | Air, sparkle, and ambient realism; naturally fades with age. | Cymbals, acoustic air, mosquito tones. |
Frequently Asked Questions: Audio Frequency Generation
Why use a pure Sine wave versus Square or Sawtooth?
A sine wave contains only a single fundamental frequency with zero harmonic overtones, making it ideal for clinical hearing checks and acoustic measurements. Square and sawtooth waves contain infinite odd or all harmonics, resulting in a buzzing synthesizer tone rich in timbre.
Why can’t I hear frequencies above 15,000 Hz or below 30 Hz?
Sub-bass below 30 Hz requires physical subwoofers capable of moving significant air volume, which laptop or phone speakers physically cannot reproduce. High treble above 15 kHz declines naturally with adult age and depends heavily on headphone tweeter fidelity.
How does 432 Hz compare to standard 440 Hz?
440 Hz is the universally accepted standard concert pitch adopted by ISO in 1955. 432 Hz is approximately 31.8 cents flatter and favored by enthusiasts for meditation and organic physical resonance with natural mathematical ratios.
How do stereo binaural beats stimulate brainwaves?
When distinct frequencies are delivered independently to each ear via stereo headphones, the superior olivary complex in the brainstem integrates the signals and entrains brainwave oscillations to match the difference frequency (such as 10 Hz for Alpha state relaxation).