Processing Settings Print

A recipe is the quickest way to a good sound (see Choosing Your Sound: Recipes and Processors). This article explains each setting on a stream's Edit page, for when you want to fine-tune.

The strip at the top of the page shows the processing chain in order: Source ? Pre-EQ ? master_me ? Autogain ? Broadcast ? Stereo Tool ? Loudness / limiter ? Encoders. Stages that are switched off are greyed out.

Pre-processing

• Rumble / high-pass filter: removes low rumble that wastes loudness. 20 to 30 Hz for music, 70 to 90 Hz for speech.
• Bass shelf (100 Hz) and Treble shelf (8 kHz): gentle tone correction. Plus or minus 2 dB is usually enough.
• Stereo width: below 100% narrows, above widens. Above 120% costs codec bits, so keep it near 100% for low bitrates.
• Sum to mono: turns the stream into mono.
• Dynamic level normaliser (simple AGC): only use it when you aren't using master_me, Broadcast or Stereo Tool, which level the audio themselves.

master_me

• Preset: the starting sound, including our own Broadcast loud, Talk radio / live DJ, Gentle, Bass-heavy, Rock / live and Low bitrate presets.
• Mode: Full mastering on its own, or Leveler only to feed Stereo Tool an even level.
• Target loudness: -14 LUFS for music, -16 for talk.
• Brickwall ceiling: the highest peak level.

Autogain

Measures loudness and smoothly moves the gain towards the target, without compressing the sound.

• Target loudness: about -16 LUFS on its own, about -18 in front of Stereo Tool.
• Reference: how fast it reacts. The default (geometric mean) is a good balance.
• Silence threshold: below this level the gain is held, so pauses and fades aren't pumped up.
• Maximum boost and Integrated history: how far and over how long it may raise the level.

Broadcast processor

• Style: Gentle (about -14 LUFS), Balanced (about -11) or Loud (about -9 to -10).
• Extra loudness (limiter drive): each +1 dB is about 1 LU louder, with more limiting. Back off if it sounds squashed.
• Bass weight (below 120 Hz) and Presence & air (above 2.5 kHz): tone to taste. Keep Presence at or below 0 for low-bitrate outputs.
• Ceiling: the highest peak level.

Use the Broadcast processor instead of Stereo Tool, never together.

Stereo Tool

Covered in Using Stereo Tool: Licence Keys, Presets and Live Tuning.

Final loudness & safety limiter

• EBU R128 loudness normalisation: transparent loudness matching to a LUFS target.
• True-peak safety limiter: a final ceiling. -1 dB stops MP3 and AAC players from clipping; use -1.5 dB for 64k and below. Stereo Tool already limits its own output, so this is mainly for the free processors and plain streams.

Saving

Click Save & apply. The stream restarts with the new settings (a 2 to 5 second gap). Use the A/B listen bar to compare the result with your original.