About

Professional audio mastering usually requires expensive outboard gear or CPU-heavy Digital Audio Workstations (DAWs). For the average user, simply adjusting the tonal balance of a recording or calibrating headphones is a complex hurdle. Standard operating system equalizers are often hidden, limited to 3 bands, or induce phase distortion. This tool solves the accessibility gap in high-fidelity audio processing. It provides a studio-grade signal chain directly in the browser, utilizing 32-bit floating-point math for transparent sound manipulation.

Accuracy is critical when correcting audio. A blind boost at 60 Hz might add power, but without a compressor, it introduces digital clipping (distortion). This application features an integrated Dynamics Compressor at the end of the chain, ensuring that even aggressive EQ moves remain within the safe 0 dBFS limit. Furthermore, the Privacy-First Architecture processes 100% of data locally via the Web Audio API. Whether you are a podcaster cleaning up a voice track, a gamer enhancing footsteps, or an audiophile calibrating flat headphones, this tool provides the mathematical precision required for the job.

Formulas

The equalizer uses a series of Biquad IIR (Infinite Impulse Response) filters. The magnitude response H(f) for a peaking filter is determined by the center frequency f_c, the gain G, and the Quality Factor Q.

H(s) = s² + sQ + 1s² + sQ ⋅ A + 1

Where A = 10^G/40. To prevent digital clipping when G > 0, the output is passed through a Dynamics Compressor which reduces the dynamic range if the amplitude exceeds the threshold T.

y(t) =

{

x(t) if x ≤ TT + x(t) − TRatio if x > T

Reference Data

Frequency Band (f_c)	Audio Role	Target Instruments	Correction Strategy
31 Hz	Sub-Bass / Rumble	Synth Sub, Kick Drum decay	+ Boost for cinema shake. − Cut to clean headroom.
62 Hz	Bass Foundation	Kick Drum punch, Bass Guitar	+ Adds "thump". − Removes boominess.
125 Hz	Body / Warmth	Male Vocals, Snare weight	− Cut to fix "muddy" mixes.
250 Hz	Resonance	Acoustic Guitars, Pianos	− Cut to reduce "boxiness" in small rooms.
500 Hz	Mid-Range Texture	Background vocals, Horns	+ Adds forwardness. − Creates a "hollow" sound.
1 kHz	Attack / Clarity	Percussion snap, Guitar strings	+ Improves intelligibility.
2 kHz	Definition	Lead Vocals, Synths	Critical for human hearing. Adjust gently.
4 kHz	Presence	Vocal consonants, Tom drums	+ brings sound "closer" to the ear.
8 kHz	Brilliance / Sibilance	Cymbals, "S" sounds	− Cut to De-ess (remove harshness).
16 kHz	Air / Atmosphere	Reverb tails, Hi-Hats	+ Adds expensive "sheen" or "sparkle".

Frequently Asked Questions

System volume controls the amplifier power sent to your speakers. The "Preamp" in this tool controls the digital gain of the file *before* it hits the equalizer. If your file is too quiet, boosting the Preamp gives the EQ more signal to work with. If you are boosting bass heavily, lowering the Preamp creates "headroom" to prevent distortion.

Stereo Width uses Mid-Side (M/S) processing. It separates the audio into "Center" (Mono) and "Side" (Stereo) information. By increasing the volume of the Side channel relative to the Center, the soundstage feels wider and more immersive. However, overusing this can cause phase cancellation when played back on mono devices.

Currently, this tool is optimized for file processing (Mastering). While the Web Audio API supports microphone input, this interface focuses on high-quality rendering of pre-recorded material to ensure the export is bit-perfect.

Yes. The "Headphone Calibration" presets attempt to flatten the frequency response curve of popular models (like Sony XM4 or AirPods). Manufacturers often boost bass and treble (V-shape). These presets invert that curve to give you a neutral, reference-grade sound.

Yes. The browser's decoding engine converts all input audio into an internal 32-bit floating-point buffer. This allows you to manipulate high-resolution audio without losing dynamic range, even if the exported file is downsampled to 16-bit for compatibility.