Codec Toolbox

Name: Codec Toolbox
Price: 52.97 USD
Author: Sonnox

by Sonnox · Utility · Codec audition and encoder

Not rated yet

Codec Toolbox lets you hear how a mix will sound as MP3, AAC or iTunes+ in real time, then batch-encode the files.

It has Clip Safe protection, metadata and loudness monitoring, and costs £39.99 (about $52.97).

Best for: Mix Bus, Mastering. Genres: all genres.

Keywords: metering, mastering, full mix, standalone app, beginner-friendly, bus processing, lo-fi, mix bus, mixing, simple, utility.

What it does

Codec Toolbox is Sonnox's tool for hearing what lossy encoding does to a mix before you deliver it. It was developed with Fraunhofer and pairs a plugin for real-time audition with a standalone manager for batch encoding.

Codecs: MP3, AAC and iTunes+ (Apple AAC). The 2014 Sound On Sound review also listed HE-AAC, HE-AAC v2 and MPEG Surround.
Real-time audition: switch between the source and the encoded-then-decoded version while you mix or master, at different bitrates.
Clip Safe: adjusts gain so the decoded file doesn't clip.
Metering: level and loudness meters, a noise-to-mask display (nine frequency-band LEDs) that shows where the codec degrades the sound, and an OVERS meter for clipping on decode.
Codec Toolbox Manager: a standalone app that batch-encodes many files to several formats at once.
Metadata: add and edit tags and cover art as part of the encode.

Source: Sonnox product page

When to use it

Codec Toolbox is the pick when the question is how a master survives MP3 or AAC, not how loud it is. Unlike Insight 2 or Youlean Loudness Meter 2, it is not a full loudness suite; its meters focus on codec noise and decoding overs. Where REFERENCE 3 compares your mix with reference tracks, Codec Toolbox compares your mix with its own encoded version. Its batch Manager also handles the actual encoding and tagging, which none of those meters do.

Best for: mastering for lossy formats, checking codec artefacts and clipping, and batch MP3/AAC delivery with metadata.
Genres: any; also podcasts and spoken word.
Look elsewhere if: you mainly need loudness metering for streaming targets (Youlean Loudness Meter 2 or Insight 2), or blind ABX tests between codecs, which Sonnox's Pro-Codec offers and this does not.
Tip: watch the noise-to-mask and OVERS meters early in the mix, not just at the end, to catch codec problems while they are easy to fix (MusicTech).

What producers say

Reviewers at launch saw it as a cheap, practical tool, with a basic interface the main complaint.

Sound On Sound (Sam Inglis, January 2014) called it "highly affordable" and easy to use, and praised the batch, metadata and fast encoding; it found the interface "a little basic in some respects".
MusicTech (February 2014) gave it Choice and Value awards and found it "hard not to recommend", noting only that it is not the most exciting tool.
Criticisms: a fixed codec list, no way to audition several codecs at once, and no blind ABX testing (SOS).

Where to buy

Sonnox: $52.97 (£39.99 converted to USD (ECB rate, 29 Sep 2026))

Tutorials and reviews

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