---
title: "Discussion on \"Building an IEC 61672 Compliant A-Weighting Decibel Filter with the Web Audio API\" | Hashnode"
description: "Discussion on \"Building an IEC 61672 Compliant A-Weighting Decibel Filter with the Web Audio API\". How to translate analog acoustic transfer functions into digital biquad filters, handle browser AGC distortion, and measure sound levels in real-time."
url: "https://hashnode.com/posts/web-audio-api-decibel-meter-dsp/6ad85cb8026d1ca495946257"
---

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# [Building an IEC 61672 Compliant A-Weighting Decibel Filter with the Web Audio API](https://soundleveltest.hashnode.dev/web-audio-api-decibel-meter-dsp?utm_source=hashnode&utm_medium=feed)

How to translate analog acoustic transfer functions into digital biquad filters, handle browser AGC distortion, and measure sound levels in real-time.

Oct 21 · 6 min read · soundleveltest.hashnode.dev  
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## Written by

[Nayeem SoundTest](https://hashnode.com/@nayeemsoundengg)

@nayeemsoundengg · Los Angeles, USA

  
[View profile](https://hashnode.com/@nayeemsoundengg)

Online sound level meter | Measure noise in decibels.

Hi, I'm Nayeem, the software developer behind SoundLevelTest.com. I built the site to provide simple, browser-based tools that help people test and understand sound using devices they already have.

## Responses 1

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[Indie Ship Log](https://hashnode.com/@indieshiplog)

[Oct 21](https://hashnode.com/posts/web-audio-api-decibel-meter-dsp/6ad85cb8026d1ca495946257/comment/6ad881aa87b2f60f680ca776)

The AGC note is the part I would have missed. I build small browser tools on my own, and I keep treating getUserMedia audio as the raw mic when the browser has already flattened it for calls. Turning echo cancellation, noise suppression, and auto gain off before the filters is the unglamorous step that makes the reading mean anything.