Dominant Frequency Finder

Use this dominant frequency finder and real-time spectrum analyzer to identify the single strongest frequency in any sound. See energy dominance %, frequency band, nearest musical note, and 10-band octave analysis. Four analysis modes: General, Room Resonance, Hum/Noise Identifier, and Tinnitus Matcher. 100% browser-based, no downloads, no audio uploaded.

Dominant Frequency Finder Tool

Understanding Your Results

Dominant Frequency vs. Fundamental Frequency

The dominant frequency is the frequency with the highest energy (loudest amplitude) in the spectrum at this moment — not necessarily the lowest one. A guitar string playing A2 (110 Hz) may have its dominant energy at 220 Hz (the octave harmonic) if the body resonates more strongly there. This is different from the fundamental frequency (the true lowest pitch) which requires harmonic analysis. Use the Fundamental Frequency Finder if you need F0.

Energy Dominance %

The Energy Dominance bar shows what percentage of the total spectral power is concentrated in the dominant peak's neighborhood. 70%+ means a very pure, strong single-frequency sound (sine wave, tuning fork, steady hum). 30–60% is typical for instruments and voices. Below 20% means the sound is broadband noise or has many competing frequencies — no single frequency clearly dominates.

Frequency Band Labels

The colored badge classifies the dominant frequency into one of seven standard audio bands: Sub-bass (20–60 Hz) — felt more than heard, bass rumble, HVAC. Bass (60–250 Hz) — kick drum, bass guitar, male voice fundamental. Low-mid (250–500 Hz) — warmth of instruments, muddiness zone. Mid (500 Hz–2 kHz) — presence of most instruments and voices. High-mid (2–4 kHz) — attack, consonants, harshness zone. Presence (4–6 kHz) — clarity, cut-through, breath sounds. Air (6–20 kHz) — shimmer, sibilance, high harmonics.

Octave Band Analyzer

The 10-band analyzer follows standard acoustic measurement practice (ISO 266), showing peak energy in each 1-octave band centered at 31.5 Hz, 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz. The band containing the dominant frequency is highlighted. This is the same standard used in professional noise measurement and room acoustic analysis.

Secondary Peaks

The Secondary Peaks list shows the next three strongest frequencies after the dominant. This is valuable for harmonic series analysis — if the dominant is 100 Hz and you see 200 Hz, 300 Hz as runners-up, the source is likely a 100 Hz fundamental with its overtones, producing the characteristic inharmonic distortion pattern of a motor or transformer. In Hum mode, runners-up often reveal whether the noise source belongs to the 50 Hz or 60 Hz family based on which interharmonic sequence appears most consistently. For deeper analysis of harmonic relationships in musical instruments or voice, the Fundamental Frequency Finder applies harmonic product spectrum analysis to extract the true F0.

Analysis Modes

General — flat response across 20–20,000 Hz. Best for music, voice, and unknown sources. Room Resonance — narrows to 20–800 Hz and draws harmonic markers (×2, ×3, ×4…) of the dominant peak to help identify room modes and standing waves. Hum/Noise ID — narrows to 20–600 Hz and draws the 50 Hz family (purple: 50, 100, 150, 200 Hz) and the 60 Hz family (orange: 60, 120, 180, 240 Hz) as reference gridlines so you can immediately identify power line interference. Tinnitus — restricts search to 2–16 kHz where tinnitus most commonly occurs and enables the Fine-tune slider (±200 Hz) for precise frequency matching with the tone playback.

Tone Match & Fine-Tune

The Play Tone button generates a pure sine wave at the detected dominant frequency. As the dominant frequency updates, the tone tracks it in real time. In Tinnitus mode, the Fine-tune slider lets you offset the playback frequency by up to ±200 Hz to match the exact pitch you hear — useful for identifying tinnitus frequency for audiologist documentation. Keep the tone volume low to avoid feedback with the microphone.

FFT Resolution & Averaging

The FFT Size setting controls frequency resolution: 8192 bins at 44.1 kHz gives ~5.4 Hz per bin; 32768 gives ~1.3 Hz. Larger FFT = better frequency precision but slightly slower response. The Averaging setting controls temporal smoothing: Fast shows every frame (noisy but responsive), Normal averages 4 frames, Smooth averages 10 frames. For steady hum identification use Smooth; for transient sound bursts use Fast.

Frequency Stability Indicator

Below the main Hz reading, a stability indicator shows variance over the last 10 readings: ● STABLE ±N Hz — the dominant frequency is holding steady (pure tone, steady hum, room mode). ◐ DRIFTING — slight pitch variation (instrument, voice, variable-speed fan). ○ UNSTABLE — frequency is changing rapidly (transient sound, broadband noise). Always wait for a STABLE reading before recording a tinnitus or hum frequency for documentation.

Keyboard Shortcuts

Space — Start / Stop. H — Hold / Resume the display. C — Auto-calibrate noise floor (stay silent for 1.5 s). T — Toggle tone playback on / off. 1 — General mode. 2 — Room mode. 3 — Hum/Noise mode. 4 — Tinnitus mode. All shortcuts are disabled while typing in input fields.

Identifying Hum & Noise Sources

Electrical and mechanical hum follows predictable harmonic patterns based on the power line frequency in your region. For accurate audio hum diagnosis, use the quick-reference table below to identify which harmonic family your hum belongs to:

Room Resonance & Standing Waves

Every room has natural resonant frequencies — called room modes or standing waves — where sound is reinforced by reflections between parallel walls. These cause excessive bass buildup at certain spots in the room.

How to Find Room Modes

Switch to Room Resonance mode, play a bass sweep (20–300 Hz) or white noise through a speaker, and watch the dominant frequency display. Move around the room — the dominant Hz will change as you enter different mode patterns. The harmonic markers on the spectrum (×2, ×3, ×4) show the modal series: if the room resonates at 60 Hz, you'll also see energy at 120 and 180 Hz.

Calculating Room Modes

The fundamental axial room mode frequency for a dimension L is: f = 343 / (2L) (speed of sound ÷ twice the dimension). A 3-metre wall has f = 343/6 ≈ 57 Hz. Three dimensions (length, width, height) each produce a mode series. Use the dominant frequency you find to work backwards: L = 343 / (2f).

What to Do About Room Modes

Bass traps placed in corners (where modes are strongest) absorb low-frequency energy. Parametric EQ on your speaker output can cut the dominant room mode frequency with a narrow Q to avoid affecting neighbouring bands. Asymmetric room layouts and diffusers reduce flutter echo and standing wave buildup. The Dominant Frequency Finder gives you the exact frequency to target — and you can verify the cut is working by re-measuring with the tool after adjusting. To generate a precise test tone at the problem frequency for measurement, use the online tone generator.

Matching Tinnitus Frequency

Tinnitus is a phantom sound perception — typically a ringing, buzzing, or hissing — heard in one or both ears in the absence of an external source. This tool's Tinnitus mode works as a tinnitus frequency matcher: play a reference tone and fine-tune it until it matches what you hear, giving you a documented Hz value for audiologist evaluation or therapeutic approaches.

How to Use Tinnitus Mode

1. Switch to Tinnitus Mode

   Click Tinnitus in the mode switcher. This constrains the search to 2–16 kHz (where most tinnitus occurs) and enables the Fine-tune slider for precise matching.

2. Enable Tone Playback

   Click Play Tone. You'll hear a sine wave. Use the Fine-tune slider to adjust the frequency up or down until the external tone sounds as close as possible to the tinnitus you perceive.

3. Record the Frequency

   Once matched, the displayed Hz value is your tinnitus frequency. Click Copy Reading or Export CSV to save it for your audiologist. Most tinnitus falls between 4–8 kHz; pure-tone average frequencies correlate with hearing loss patterns.

Note: This tool is for informational and self-assessment purposes only. It is not a medical device and cannot diagnose tinnitus or hearing loss. Consult a licensed audiologist for clinical evaluation and treatment.