Albatross Stereo Widener

Width — the main spread control

Width is a gain on the Side channel: 0–200%, default 100%. Since the Side is exactly what cancels in a mono sum, changing Width alters the stereo image without ever touching the mono fold-down.

• 0% — The Side is silenced. The track collapses to pure mono.
• 100% — Unchanged. The image passes through as it entered.
• 100–150% — A natural widening. Good on buses and masters where you want more spread without artefacts.
• 150–200% — Aggressive. The sides are boosted hard; watch the correlation meter and check mono.

Width only scales existing Side content, so on a fully mono source (no Side to begin with) it does nothing — use Depth for that instead.

Depth — width from mono

Depth (0–100%, default 0%) disperses a copy of the Mid through a cascade of eight fixed all-pass filters and injects it into the Side. A mono or dead-centre source gains a wide, phasey, moving stereo image that Width alone can't create.

• 0% — Off. No decorrelation. The Side is only the natural stereo content.
• 20–50% — Subtle to moderate. A mono synth or bass gains believable width without an obvious effect.
• 50–100% — Strong. A big, enveloping spread. Best on sustained textures, pads and leads.

Because the injected copy lands in the Side, it too cancels in mono — no comb-filtering of the fold-down. Depth is safe to push hard on bass-friendly material as long as Bass Mono is set above your sub.

Bass Mono — the crossover mono-maker

Bass Mono (20–400 Hz, default 110 Hz) is a true Linkwitz-Riley crossover, not a shelf. The Side gets a 48 dB/oct high-pass and the Mid gets the crossover's matching all-pass, so the two stay phase-aligned. Everything below the cutoff folds cleanly to the centre.

The number is where the image is genuinely mono. That's worth spelling out, because most mono-makers label the crossover corner instead — and a corner is only 6 dB down, meaning half the Side is still there at the frequency on the dial. Albatross puts the corner 1.5× above the dial, so at the number itself the Side is already ~28 dB down (4% of the Mid) and the transition spans the octave above. Dial 110 Hz and you get −28 dB of Side at 110 Hz, −48 dB at 82 Hz, −76 dB at 55 Hz. Set it to where you want mono, not an octave or two higher to compensate.

• 20 Hz — Effectively off. The whole spectrum can be widened.
• 80–120 Hz — Typical for full mixes and masters. Locks the sub while leaving the low-mids free to spread.
• 120–200 Hz — For bass music. Keeps sub, kick and the body of a bassline dead-centre and mono-solid.

The crossover runs last, after the Mix, so "mono below fc" holds even for a partial dry/wet blend. The cutoff sweeps click-free. Set it just above the fundamentals you want to keep centred.

Tilt & Center — shaping the balance

Tilt (−100 to +100%, default 0%) is a ±6 dB shelf about a 700 Hz pivot on the Side — it decides where the width lives. Center (−6 to +6 dB, default 0 dB) trims the Mid.

• Tilt negative — Widens the lows and tightens the highs. A broad, weighty spread.
• Tilt positive — Widens the highs (air and shimmer) while keeping the low-mids focused.
• Center up (+dB) — Pushes the vocal / kick / bass forward through a wide mix.
• Center down (−dB) — Pulls the centre back so the sides breathe wider around it.

Tilt and Center are the fine-tune pair after Width and Depth. Raise Width and lower Center for an airy, spacious feel; reverse them for a focused, upfront one.

Metering — goniometer & correlation

The hero display is a live goniometer (vectorscope) with a −1 · 0 · +1 correlation bar beneath it. The point cloud plots Mid vertically and Side horizontally, and both the cloud and the needle are coloured by correlation — green, amber, red.

• Tall, narrow cloud — Mono-leaning. Little stereo content.
• Wide, round cloud — A healthy, big stereo image.
• Horizontal smear — Out-of-phase content. Check the correlation and your mono fold-down.
• Correlation ›fc Hz — The meter is banded above the Bass Mono cutoff (the label tracks the knob), because the mono lows would otherwise pin a full-band meter near +1 and hide the real image.

Green is mono-safe, amber is very wide, red is phase risk. A little amber on a wide bus is fine; sustained red means partial cancellation in mono.

Monitor, Mix & Output

The Monitor switch (Stereo / Mono / Side, default Stereo) sets what reaches the output. The audition modes force full wet — they ignore Mix — and keep the correlation meter live.

• Stereo — Normal output. This is what you render.
• Mono — The true fold-down. Flip here to hear exactly what a club, phone or vinyl cut hears, and confirm the sub holds.
• Side — Solos only what's being widened. Useful for hearing what Depth and Tilt are adding.
• Mix (0–100%, default 100%) — Dry/wet blend for subtle parallel enhancement, especially on a master.
• Output (−24 to +24 dB, default 0 dB) — Final trim after the crossover; level-match for an honest bypass A/B.

Albatross adds zero latency and is fully parallel and sub-safe, so it's safe to place anywhere in the chain.