B312-1 — Video & podcast production — The largest room in the facility, with a high 340cm ceiling and the Study-B HYBRID backdrop: hard chroma cyc + dual white/black curtain tracks (4 acoustic states)
Use Cases
Video production, multi-cam podcast, chroma-key shoots on the hard cyc, white/black curtain looks, product demos — and, in the bare-cyc S1 state, choir and instrument recording: S1's mid-band RT of 0.332s sits deliberately in the music-friendly upper half of the window, so small ensembles record in this room and are mixed in Control via the SNK-2 stagebox. The largest room at 19.78 m² with a high 340cm clear ceiling (compact decoupled build) and a 4.00m camera throw. The two former east-zone rooms are merged into this single room.
Floor Plan Position
Video/Podcast occupies the entire east zone (the former east-zone footprints, now merged), east of the buffer spine. Width is 479 cm × 413 cm deep — locked SSOT values.
Acoustic Treatment
| Element | Qty | Specification |
|---|
| Absorption panels | 6 | Rockwool RWA45 50mm, 1200×600mm, NRC 0.90 — distributed on South + West + East-south walls (not clustered, not on the curtain zone) |
| Superchunk bass traps | 6 | DEEP superchunk, 400–600mm, floor-to-ceiling — SE + SW wall corners + 4 at COL-W re-entrant angles (NOT NW; north wall is curtain) |
| 125Hz membrane traps | 4 | 4mm ply + 100mm cavity + 50mm RWA45, 1200×600, tuned ≈123Hz |
| BT-08 membrane traps (S1 fix) | 2 | Same build family retuned to f₀≈250Hz, 1200×600 (1.44 m² wall) — cures the S1 bare-cyc 250Hz build-up (0.405→0.392s); on FREE wall faces, never the cyc/backdrop walls; PROTOTYPE-FIRST |
| Deep bass soffit | 1 | Perimeter MEP bulkhead built as a bass device — ≥300mm mineral-wool fill + sealed cavity, α₁₂₅≈0.55 |
| QRD diffusers | 0 | — |
| Ceiling cloud | 28% | Rockfon RWA45 cloud, 28% floor-area coverage (kept lean to preserve the tall 340cm look) |
| Hard chroma CYC (Layer 1) | 1 | Framed cove cyclorama — North wall (full 479) + East wall north-half (206), floor cove + NE corner radius. Raft-mounted independent framing (never fixed through the isolation leaves) + Knauf 12.5mm flats ×2 + Knauf Herform 6.5mm flexible board coves + Rosco Chroma Key Green #5711 + Roscoflamex PA additive (ASTM E84 Class A route). Green = ONLY the painted cyc. |
| Dual curtain tracks (Layer 2) | 2 | Motorised tracks IN FRONT of the cyc — WHITE heavyweight molton ≥300 g/m² IFR at ~25cm + BLACK molton/velour ≥300 g/m² IFR at ~35cm off the cyc face (Gerriets JOKER 95 + TRAC-DRIVE / ShowTex Rail H100), slab-hung on isolated neoprene hangers. Deployed curtains are the primary variable mid/high absorber (S2/S3). |
| Chroma floor sweep | 1 | Rosco Chroma Floor green ramped sweep at the cyc base (infinity curve, anti-trip ramped edges) — deployed for full-body/floor shots only; installed LAST |
| In-shot area rug | 1 | ≈6 m² rug — breaks the vertical floor/ceiling flutter left by the lean cloud |
| Isolated lighting grid | 1 | Unistrut pipe grid, clamp-on fixtures, hung on isolated hangers (NOT on the decoupled ceiling) |
| Column wrap | 1 | COL-W free-standing absorptive wrap |
The 3-look concept: one room, three shooting looks — chroma GREEN on the bare painted cyc (S1), WHITE on the front curtain (S2), BLACK on the rear-look curtain (S3) — plus partial mixed sets (S4). Each look is also an acoustic state: S1 0.332s (music upper half — a FEATURE for choir/instruments), S2/S3 0.242s (speech class, marginally dry — disclosed), S4 0.262s. 125 Hz ≈0.56s in every state (geometry-driven LF tail, disclosed); the S1 250Hz build-up is cured by the 2× BT-08 retuned membranes.
RT60 Analysis — 4-State HYBRID
| State | Configuration | Use | RT60 mid (s) | Window (s) | Status |
|---|
| S1 | Bare cyc — both curtains retracted | Chroma keying + CHOIR / INSTRUMENTS | 0.332 | 0.325–0.42 (music upper) | ✓ Pass |
| S2 | WHITE molton deployed (cyc occluded) | Bright non-chroma video | 0.242 | 0.25–0.325 (speech low) | Marginal (dry) |
| S3 | BLACK molton deployed | Dark looks / interviews | 0.242 | 0.25–0.325 (speech low) | Marginal (dry) |
| S4 | PARTIAL — north deployed, east bare | Mixed sets | 0.262 | 0.25–0.42 (intermediate) | ✓ Pass |
| Band (Hz) | 125 | 250 | 500 | 1k | 2k | 4k |
|---|
| S1 bare cyc (BT-08 in) | 0.558 | 0.392 | 0.338 | 0.326 | 0.331 | 0.339 |
| S2 / S3 curtains | 0.560 | 0.324 | 0.252 | 0.232 | 0.229 | 0.233 |
| S4 partial | 0.559 | 0.340 | 0.272 | 0.253 | 0.251 | 0.256 |
State switching is an operational act, not a rebuild: the motorised tracks move the room between a live music space (S1), a dry speech studio (S2/S3) and mixed sets (S4) in under a minute. Retracted curtains still read acoustically — their stacked bundles at the track ends are modelled as 2×≈1.5 m² residual absorbers in S1.
Honest disclosures: S2/S3 at 0.242s sit just under the 0.25s speech floor — slightly dry, favoured over an over-live room on camera. 125 Hz ≈0.56s in EVERY state (geometry-driven; the deep soffit + superchunks already carry it). The S1 250 Hz build-up (0.405s no-fix) is cured to 0.392s by the 2× BT-08 membranes retuned ~250 Hz — the alternative (ceiling clouds 28→40%) was REJECTED because it drags S1 mid below the 0.325s music floor.
Boundary Build-ups
| Wall | Type | Lab STC | Field | Assembly |
|---|
| North perimeter | Concrete (street — the only concrete wall) | 65 | 58–62 | 300mm concrete + RSIC-1 + 50mm RW + 2×gyp |
| South perimeter | Gypsum stud (existing) | ~50 | 44–48 | Existing gypsum partition lined/rebuilt to STC 50 class (PW-03); D1 entry hosted here as a FRAMED opening on a steel subframe — no concrete cutting, no lintel |
| East perimeter | Gypsum leaf (existing) + new stud leaf | 62 | 55–59 | Existing gypsum leaf + ~100mm air gap (KEPT UNFILLED) + NEW decoupled stud leaf (PW-04) — B313 SERVER ROOM behind runs 24/7; never bridge the gap |
| West (W5) | Buffer spine (NEW BUILD) | 55 | 49–53 | NEW-BUILD double leaf (W-07): 2×12.5mm gyp+GG + 100mm studs+RW + 2×12.5mm gyp+GG; head sealed to slab; only sleeved SN-03 crossings penetrate it |
| Ceiling | Compact decoupled | — | — | RSIC-1 slab-hugging compact build (11cm), 2×12.5 gyp + 50mm RW; 28% Rockfon cloud, 340cm AFF |
| Floor | Float | — | — | Vinyl finish + 15cm Sylomer buildup |
Height chain: 366.4cm slab-to-slab − 15cm float floor − 11cm compact decoupled ceiling = 340cm clear (HIGH). The hanging MEP (HVAC unit / black pipe) is boxed into a perimeter bulkhead with an HVAC service hatch — the same bulkhead is built as the deep perimeter bass soffit.