Magic Master 3.9: Honest Dynamics, Quiet Pauses, AI Agents

Version 3.9 is about sound. Four changes to the processing chain, each of which
came out of a specific complaint and each measured before it was switched on.
Plus a new door for people who work through AI assistants.

Peaks are no longer clipped mid-chain

The main change of this release, and you can hear it.

Mastering is a chain: loudness normalisation, EQ, dynamics, saturation, final
limiter. Between modules the signal is kept with headroom and its peaks legally
exceed unity — that is normal, the ceiling is set by the limiter at the end. Yet
dozens of places in the chain clipped those peaks flat, just in case.

Investigating a complaint about the bass preset, we walked the chain measuring at
every step and found where the attack was lost: the very first clip flattened the
subharmonic, so every kick reached the limiter already damaged. Not compressed —
clipped, which is a different thing, and it sounds dirty.

Hot peaks now reach the final limiter intact, and loudness is set by it alone.
Measured on the file from the complaint:

crest       11.41 → 12.41 dB   (+1.0)
loudness    −12.05 LUFS        against a −12 target
True Peak   −1.01 dBTP         against a −1 ceiling

The track did not get louder or quieter — what changed is how loudness is
reached. Nothing to adjust, and it works for every preset.

The unlimiter got more precise

The "AI Unlimiter" preset restores dynamics in over-compressed tracks. It used to
decide by an absolute threshold — the same one for a quiet recording and for a
brickwalled master. The threshold is now relative, derived from the material.

Tested on a corpus of six real tracks: dynamics improved on all six, with zero
regressions. This is the rare change with no trade-off.

Pauses after stem separation are quiet now

A complaint named the defect precisely: "artefacts and bubbling" in the pauses
after separation. The investigation showed we had been fixing the wrong thing:
only 8.2% of the residual energy matches the "isolated peak" criterion, and the
old cleanup removed 1.6% of that. The other 92% is floating residue of other
instruments — and that is what bubbles.

The residual gate works on that class:

deep pauses         −15.0 dB
phrase boundaries   −0.2 dB     (no clicks)
vocals              −0.125 dB   (essentially untouched)

Tone correction leaves dense material alone

Automatic tone correction had an honest problem: on dense, saturated material it
made things worse — all four user ratings of that feature were one star. It now
steps aside on such input and works as before where it helps.

A door for AI agents

If you work through an assistant — Claude, ChatGPT or another — Magic Master is
now available to it directly: an MCP server at /mcp, OAuth 2.1 sign-in and
trial tokens without payment. The assistant sends a track for mastering and
returns the quality passport as a card inside your chat.

The public API grew too: registration and sign-in are open, there is a limits
endpoint GET /api/v2/limits, machine-readable errors and an OpenAPI
description. None of this is needed to use the website.

Small things you can see

• On laptop screens narrower than 1402 pixels the "Master for free" button no
  longer ran off the edge of the menu — and that is one in five of our desktop
  visitors.
• The "What's new" dialog no longer mixes up versions: heading, text and link
  now describe the same release.
• The key finder gained a section on tempo: how it is computed, why key and BPM
  fail independently of each other, and how to catch the doubling error in ten
  seconds when 140 BPM arrives as 70.
• Album mastering got its own page, with anchor loudness and a quality passport
  for every track.

What comes next

We are watching bass dynamics and any complaints about a "dirty top end"
separately: the chain change also affects what comes after it — the exciter and
imager now receive a hot signal. If you hear a difference, better or worse, the
rating under your mastering result reaches us and gets read.