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SPIRAL by GLENDER - Free Online Audio Mastering Engine
SPIRAL by GLENDER SPIRAL BY GLENDER Local mastering / analysis / export
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Features How it works Formats Free FAQ Blog VS Help Open SPIRAL
TRACK · ANALYSIS · MASTER · EXPORT — BUILT BY GLENDER

MASTER A TRACK
PEOPLE feel —
AND A SYSTEM
THAT MAKES IT hit.

A focused local mastering workspace for fast decisions, clean monitoring, and export-ready audio without cloud storage or unnecessary noise.

See how it works
100% LOCAL NO UPLOADS FREE · NO ACCOUNT WAV EXPORT

SPIRAL INTO SOUND.

LOCAL AUDIO ENGINE0 uploads

ANALYZE

Read level, spectrum, dynamics, phase, and true peak.

SHAPE

Apply a controlled mastering chain with restrained defaults.

EXPORT

Render WAV locally with the selected precision.

+
DROP YOUR MIX HERE
or click to select
MP3 / WAV / FLAC / AAC / OGG / M4A
LUFS · TRUE PEAK · SPECTRUM · DYNAMICS · CORRELATION · CLIPPING · HPF · CORRECTIVE EQ · SATURATION · COMPRESSION · TONAL EQ · M/S CONTROL · BRICKWALL LIMITER · A/B LEVEL MATCH · REFERENCE TRACK · WAV 16/24/32F ·
LUFS · TRUE PEAK · SPECTRUM · DYNAMICS · CORRELATION · CLIPPING · HPF · CORRECTIVE EQ · SATURATION · COMPRESSION · TONAL EQ · M/S CONTROL · BRICKWALL LIMITER · A/B LEVEL MATCH · REFERENCE TRACK · WAV 16/24/32F ·

The difference is decided before the render.

Mastering by feel with no reference costs takes. SPIRAL puts the readouts, the chain and the comparison in front of you first.

WITHOUT A SPIRAL PASS
The export is committed on feel by ear
LUFS and true peak checked after release too late
No reference — comparison comes from memory no target
Every session starts from zero no recall
1take you commit to
0targets measured first
0references compared
0settings remembered
Uploads, subscriptions and cloud storage — none of it runs before the judgement call.

The render decides for you.

WITH SPIRAL
Six readouts measured before you touch a knob
A/B against the original, level matched
A reference track sets the target for loudness and tone
The chain is visible, adjustable and restrained by default
6analysis readouts in real time
7chain modules from HPF to limiter
100%processing on your machine
0uploads, accounts or storage
$0 — free engine, no account. Your mix stays on your machine.

One local workspace instead of a render button.

One local engine for fast mastering decisions.

Analyze the mix, shape the chain, compare loudness, and export without uploading the track anywhere.

ANALYZE — read before you decide
LUFS True peak Spectrum Dynamics Phase Clipping
SHAPE — the mastering chain
HPF Corrective EQ Saturation Compression Tonal EQ M/S control Limiting Smart presets
COMPARE — original against mastered
A/B switch Level match Loop sections Reference target LUFS delta Spectrum match
ASSIST — the mastering intelligence
Ask the assistant Track context Specific advice Real-time guidance Reference-aware Plain language
0uploads — the mix never leaves the browser
6load formats, decoded locally
7chain modules from HPF to brickwall
100%of the processing runs on your machine

How a session runs. Four moves, one workspace.

Drop the mix once. Everything after that — analysis, chain, comparison, render — happens in the same local window.

Read the mix before you touch it.

SPIRAL decodes the track locally and reports what actually matters for the master: loudness, peaks, dynamics, tone and stereo behaviour.

  • LUFS integrated and short-term, against your target.
  • True peak and inter-sample clipping, before it reaches the renderer.
  • Spectrum, dynamics and stereo correlation in real time.
LUFS-8.4
TRUE PK-0.8
DYN7.2
CORR+0.81
ANALYSIS · LIVE READOUTS, LOCAL DECODE

Shape with restraint, not guesswork.

The chain opens at sensible defaults: HPF, corrective EQ, saturation, compression, tonal EQ, M/S control and brickwall limiting — every module visible and adjustable.

  • Curated presets for transparent, punchy or vintage starting points.
  • Every move is audible and reversible — nothing hidden behind an auto button.
  • The limiter holds the ceiling you set; the assistant explains the rest.
HPF24 Hz
LIMITER-0.8 dB
CHAIN · HPF → EQ → SAT → COMP → M/S → LIMIT

Decide by hearing, not by louder.

Switch between original and mastered at matched loudness. Load a reference track and SPIRAL measures both, so the target is data — not nostalgia.

  • A/B switch with level match, so louder never wins by default.
  • Loop sections and judge the low end, the vocal or the top separately.
  • Reference analysis: LUFS, spectrum and dynamics side by side.
ORIGINAL-14.2 LUFS
MASTERED-8.4 LUFS
REFERENCE-8.1 LUFS
TARGET-8.4
COMPARE · LEVEL MATCHED · REFERENCE AWARE

Render WAV locally, at release precision.

When the decisions are made, export the master straight from the browser — 16-bit, 24-bit or 32-bit float. The file never leaves your machine to exist.

  • Selected precision, rendered offline for accuracy.
  • True-peak safe ceiling you control.
  • Drop another track and the next session starts clean.
EXPORT · WAV 16 / 24 / 32F · LOCAL RENDER
THE DESK RULE
“Nothing gets exported before the readouts, the chain and the comparison agree. That is the whole method.”
Read the help guide →

Look inside the studio.

ANALYSIS · WAVEFORM / SPECTRUM
CHAIN · CORRECTIVE & TONAL EQ
M-8.6
S-9.1
GR-2.4
MONITOR · M/S LEVELS & LIMITER GR
A · ORIGINALLOOP 16
B · MASTEREDLOOP 16
COMPARE · MATCHED A/B LOOP
FORMATWAV 24
CEILING-0.8 dB
EXPORT · LOCAL RENDER
ATO 01 · LOCAL FIRST

Your mix stays on your machine.

SPIRAL runs on the browser's Web Audio engine. The track is decoded, analysed and rendered locally — no upload, no account, no storage. That is also why monitoring is honest: what you hear is the file you have.

Close the tab and nothing of your music remains anywhere else.

Read the privacy page → About the engine →
UPLOADS0
ACCOUNTS0
LOCAL100%
LOCAL · NO CLOUD AUDIO, EVER
ATO 02 · DECISIONS FIRST

Decisions over knobs. Every move explained.

The defaults are restrained on purpose, and the built-in assistant reads your analysis and reference before it says anything. The goal is a master you can defend in one sentence — not a preset roulette.

Compare, listen, adjust. Nothing is applied behind your back.

See the chain → How it compares →
PRESETBALANCED
ASSISTANTCONTEXT READY
HPF24 Hz
SAT34%
COMP-2.4
CHAIN · RESTRAINED DEFAULTS, VISIBLE MOVES
ATO 03 · RELEASE READY

Export once. Ship everywhere.

Render the master as WAV at the precision your distribution asks for, with a true-peak safe ceiling. The same session keeps the original for comparison and the analysis for the notes that follow.

Every format → Read the mastering desk →
MASTERWAV 24 · -8.4
CEILING-0.8 dBTP
STREAMING · CLUB · ARCHIVE
EXPORT · ONE PASS, RELEASE READY

Load anything. Export the master.

Six audio formats in, professional WAV out. No plug-in, no installer, no conversion step first.

MP3 LOAD

The everyday reference. Decoded locally in seconds.

WAV LOAD · EXPORT

The studio format — read, mastered and rendered at precision.

FLAC LOAD

Lossless source, no conversion step.

AAC / M4A LOAD

Apple-friendly mixes load straight from the session.

OGG LOAD

Open format sources for the archive.

WAV 16 / 24 / 32F EXPORT

Pick the precision and render offline, true-peak safe.

Start with your mix → DROP A TRACK · FREE · NO ACCOUNT

One session. Everything in the chain.

Nothing hidden, nothing auto-magic. The full signal path is visible from the first readout to the final ceiling.

HPFCORRECTIVE EQSATURATIONCOMPRESSIONTONAL EQM/S CONTROLBRICKWALL LIMITERLUFSTRUE PEAKSPECTRUMPHASESMART PRESETS
FREE LOCAL MASTERING TOOL

Free to use. No uploads. No account wall.

SPIRAL runs in your browser using the Web Audio engine. Your track stays on your machine while you analyze, master and export.

FREE
QUESTIONS

Good to know, before you drop a track.

No. The audio is decoded and processed inside your browser with the Web Audio engine. Nothing is uploaded, stored or shared — not even for analysis.

Yes. The engine is free to use and needs no account. There is no export paywall: you can analyze, master and render WAV without paying or signing up.

MP3, WAV, FLAC, AAC, OGG and M4A. The file is decoded locally when you drop it on the engine.

A mastered WAV rendered locally, at 16-bit, 24-bit or 32-bit float precision, with the ceiling you set on the limiter.

Loudness (LUFS), true peak and clipping, dynamics, spectrum, stereo correlation and phase — the six readouts that decide a master before anything is rendered.

It is a fast, honest first pass and a decision workspace: it shows you what the mix needs and renders a solid master locally. For a full release you still decide how far to push it.

No. SPIRAL is the website. A modern browser with Web Audio support is the only requirement.

From the mastering desk.

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Start mastering in your browser.

FROM THE DESK

Weekly LUFS targets, EQ workflows & mastering techniques.

Short notes on loudness, mix prep, A/B decisions and release-ready exports. No spam, just useful audio workflow ideas.

RUNS LOCALLY · FREE · NO ACCOUNT NEEDED

SPIRAL
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Get the complete SPIRAL Glender Afro House Production Blueprint — free.

Arrangement Layering Mix Master
SPIRAL BY GLENDER · LOCAL MASTERING / ANALYSIS / EXPORT
SPIRAL by GLENDER SPIRAL BY GLENDER Local mastering / analysis / export

Free audio mastering engine. Runs locally. No data stored. Built by GLENDER, for producers who want honest decisions before release.

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