Online Audio Equalizer
Upload any audio file and shape it with a professional 10-band parametric EQ. Boost bass, add vocal presence, cut harshness — all in your browser. No uploads to servers, no account required.
Upload a file · Boost, EQ, export · 100% in your browser
Equalization is the single most powerful tool in audio engineering. Before compression, before limiting, before any effect — EQ shapes the fundamental tonal character of a recording. A muddy podcast becomes clear with a 300 Hz cut. A thin guitar recording gains warmth with a 200 Hz shelf boost. Dull vocals snap to life with 3 dB at 3 kHz. Yet most free online audio tools either skip EQ entirely or offer a crude 3-band bass/mid/treble control that lacks the precision to solve real problems. Hearably Studio provides a full 10-band parametric equalizer with professional-grade control, running entirely in your browser.
The 10 bands are spaced at standard ISO frequencies: 31 Hz, 62 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz. Each band uses a biquad peaking filter (also called a bell filter) with adjustable gain from -12 dB to +12 dB. This gives you surgical control over every region of the frequency spectrum — from the deepest sub-bass rumble that you feel more than hear, through the critical midrange where vocals and instruments live, up to the highest treble frequencies that add "air" and sparkle to a mix.
Understanding what each frequency range does is the key to effective equalization. The sub-bass region (31-62 Hz) controls the physical rumble and weight — boost here for chest-thumping bass in electronic music, or cut to reduce low-frequency noise from air conditioning and traffic. The bass region (125-250 Hz) is where warmth and body live, but also where "muddiness" accumulates if too much energy builds up. The low midrange (500 Hz-1 kHz) is the "boxy" zone — cutting 500 Hz by 2-3 dB can open up a congested mix dramatically. The upper midrange (2-4 kHz) is the "presence" band where speech intelligibility is determined and where guitars and vocals cut through a mix. And the treble region (8-16 kHz) controls "air," sibilance, and the perception of detail.
Hearably Studio's EQ uses BiquadFilterNode peaking filters from the Web Audio API — the same filter topology used in professional DAWs like Pro Tools, Logic Pro, and Ableton Live. Each filter computes second-order IIR (Infinite Impulse Response) coefficients that shape the frequency response curve with mathematical precision. The Q factor (bandwidth) is preset to musically useful values that provide broad, natural-sounding curves rather than the narrow surgical notches used in feedback elimination. This means you can boost or cut freely without creating harsh resonances or unnatural-sounding artifacts.
The tool supports every common audio format — MP3, WAV, FLAC, OGG, AAC, and M4A. You can drag and drop a file or click to browse, adjust the EQ bands visually, preview the result in real time, and download the processed audio. Everything runs client-side via the Web Audio API's OfflineAudioContext for final rendering. No audio data leaves your machine. Free users get full 10-band EQ control with WAV export. Pro users unlock MP3 export, batch processing to EQ multiple files with identical curves, A/B preview to toggle between original and processed audio, and preset EQ curves optimized for common scenarios like vocal clarity, bass boost, and vinyl warmth.
How Digital Parametric EQ Works — Biquad Filters Explained
Every band in Hearably Studio's EQ is implemented as a BiquadFilterNode configured in "peaking" mode — a second-order IIR (Infinite Impulse Response) filter that boosts or cuts a bell-shaped region of the frequency spectrum. The filter is defined by three parameters: center frequency (where the bell peaks), gain (how much boost or cut in dB), and Q factor (how wide or narrow the bell is). A higher Q means a narrower band — useful for surgical removal of problem frequencies — while a lower Q creates a broad, gentle curve that sounds more musical and natural.
Mathematically, the biquad filter computes six coefficients (b0, b1, b2, a0, a1, a2) derived from the center frequency, Q, gain, and sample rate using Robert Bristow-Johnson's Audio EQ Cookbook formulas. These coefficients define a transfer function H(z) that the Web Audio API evaluates for every audio sample in real time. The frequency response — the characteristic curve showing which frequencies are boosted and which are cut — is determined entirely by these coefficients. When you adjust a slider in the studio UI, the coefficients are recalculated and applied to the filter node with a smooth parameter ramp to avoid clicks.
Ten bands of peaking EQ at standard ISO 1/3-octave centers (31 Hz to 16 kHz) provide complete coverage of the audible spectrum with musically useful spacing. The curves overlap slightly between adjacent bands, which means boosting two neighboring bands creates a broader combined boost — the same additive behavior you'd see in any professional parametric EQ. The combined frequency response of all 10 filters cascaded in series gives you a virtually unlimited range of tonal shapes, from subtle presence lifts to dramatic spectral reshaping. All processing renders through the OfflineAudioContext at faster-than-real-time speed for the final export.
How to get the best audio on Online Audio Equalizer
Cut before you boost — the golden rule of EQ
If something sounds muddy, cut the offending frequency rather than boosting everything else. Cutting 250-500 Hz by 2-3 dB often does more for clarity than boosting the highs. Subtractive EQ sounds more natural and leaves more headroom for the limiter.
Boost 2-4 kHz for vocal presence and clarity
The 2-4 kHz range is where human speech is most intelligible. If a podcast or voice recording sounds distant or buried, add 2-3 dB at 2 kHz and 4 kHz. This is the single most effective EQ move for making voices cut through.
Cut 500 Hz to reduce boxiness
The 500 Hz region is where "boxy" and "nasal" qualities live. Recordings made in small rooms, cheap microphones, and phones often have excessive energy here. A 2-3 dB cut at 500 Hz opens up the sound dramatically.
Add air with a gentle 16 kHz boost
Boosting 16 kHz by 1-2 dB adds a sense of "air" and openness to any recording. This works especially well on vocal recordings, acoustic instruments, and anything that sounds dull or lifeless. Be subtle — a little goes a long way.
Use bass boost for flat-sounding phone recordings
Phone microphones and laptop mics typically roll off below 100 Hz due to their small diaphragm size. Adding 3-4 dB at 62 Hz and 125 Hz restores the warmth and body that the recording hardware removed.
Preview in real time before committing
Use the real-time preview to audition your EQ changes on the actual audio before rendering the final file. Toggle individual bands on and off to hear exactly what each adjustment contributes. This prevents over-EQing.
Combine EQ with volume boost for best results
EQ alone doesn't increase overall loudness — it redistributes energy across the spectrum. For maximum impact, shape the tone with EQ first, then apply volume boost. The look-ahead limiter ensures the combined processing stays distortion-free.
Built for this exact use case
10-Band Parametric EQ
Professional biquad peaking filters at 31 Hz, 62 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz, and 16 kHz. Full ±12 dB range per band for surgical or broad tonal shaping.
Visual Frequency Display
See your EQ curve in real time as you adjust sliders. The visual display shows the combined frequency response of all 10 bands, so you can see exactly how your adjustments shape the audio spectrum.
Real-Time Audio Preview
Hear your EQ changes instantly on the actual audio file. Toggle the EQ on and off, compare before and after, and dial in the perfect tone without waiting for a full render.
All Major Formats Supported
Drop in MP3, WAV, FLAC, OGG, AAC, or M4A files. The browser decodes any format to raw PCM for processing. Export as WAV (free) or MP3 (Pro). No format conversion tools needed.
Choose your method
Different situations call for different tools. Hearably gives you both.
Chrome Extension
Enhance audio live while you stream. The extension intercepts your tab's audio and processes it in real-time — volume boost, EQ, presets — without downloading anything.
- Streaming on Online Audio Equalizer, Netflix, Spotify
- Video calls on Zoom, Meet, Teams
- Any website with audio
- When you want instant, always-on enhancement
Free Online Studio
Upload an audio or video file, apply volume boost + 10-band EQ, preview in real-time, then download the enhanced WAV. Your file never leaves your browser.
- Downloaded videos or music files
- Podcast episodes you want to boost before sharing
- Voice recordings, lectures, interviews
- When you need a permanently enhanced file
Pro tip: Use a YouTube-to-MP3 tool to download the audio, then enhance it in Hearably Studio with EQ + volume boost. Perfect for offline listening, DJ sets, or sharing on social media.
Three clicks to better audio
Install
Add Hearably from the Chrome Web Store. Under 300KB, installs in seconds.
Enhance
Click the Hearably icon and tap "Enhance." Boost kicks in instantly.
Enjoy
Adjust volume, EQ, and presets. Works on any website with audio.
Frequently asked questions
What is a parametric EQ and why is it better than bass/treble controls?
A parametric EQ gives you independent control over multiple specific frequency bands — in this case, 10 bands from 31 Hz to 16 kHz. Simple bass/treble controls only split the spectrum into 2-3 broad regions, making it impossible to target specific problems like boxiness at 500 Hz or vocal presence at 3 kHz. Parametric EQ is what professional audio engineers use.
Is this online EQ tool really free?
Yes. The full 10-band parametric EQ, volume boost, multiband compressor, look-ahead limiter, and WAV export are completely free with no account required. Pro adds MP3 export, batch processing, A/B preview, and manual compressor controls.
Do my audio files get uploaded to a server?
No. All EQ processing runs in your browser via the Web Audio API. Your audio files are decoded, processed, and re-encoded entirely on your device. Nothing is transmitted to any server. The tool works offline after the page loads.
What frequencies should I boost for better vocal clarity?
For speech and vocal clarity, boost 2 kHz and 4 kHz by 2-3 dB. This targets the frequency range where human speech consonants are most prominent. Also consider cutting 250-500 Hz by 1-2 dB to reduce muddiness that masks vocal detail.
Can I use preset EQ curves instead of adjusting manually?
Yes. Hearably Studio includes preset EQ curves for common scenarios — vocal clarity, bass boost, treble sparkle, vinyl warmth, and flat (bypass). Select a preset as a starting point, then fine-tune individual bands to taste.
What audio formats are supported?
The tool accepts MP3, WAV, FLAC, OGG Vorbis, AAC, M4A, and WebM audio. The browser handles decoding for all formats. Free users export as WAV; Pro users can also export as MP3.
Will EQ changes cause distortion?
Not in Hearably Studio. Boosting EQ bands increases amplitude at those frequencies, which could cause clipping. The look-ahead limiter in the processing chain catches any peaks that would exceed the digital ceiling and smoothly reduces gain to prevent distortion. You can boost aggressively without worrying about clipping.
How does this compare to EQ in Audacity or a DAW?
The filter math is identical — Hearably Studio uses the same biquad IIR filter topology as Audacity, Logic Pro, and Pro Tools. The difference is convenience: no software to install, no learning curve, no project setup. Drop a file, adjust sliders, download. For quick EQ jobs, it is significantly faster than opening a full DAW.