# Church Active Mid Speaker — Manufacturing Package

**Product:** CAMS-1 (Church Active Mid Speaker, Rev A)  
**Use case:** Speech / worship vocals / mid-band fill for sanctuaries ≈ **300 people**  
**Architecture:** Sealed 2-way **bi-amped** active loudspeaker + heavy-duty stand  
**Quality tier:** Audiophile-grade drivers + Class-AB amplification (LM3886 ×2)

---

## System overview

```
Mic / mixer / DSP line out (XLR)
        │
        ▼
  Input buffer + limiter
        │
   Active LR4 XO @ 2.5 kHz
     ┌──┴──┐
     ▼     ▼
  MID     HF
 LM3886  LM3886
  ~50W    ~30W (padded)
     │     │
     ▼     ▼
  8″ mid  1″ soft-dome
   sealed cabinet (~22 L net)
        │
   35 mm pole → weighted stand
```

### Why this design for a 300-person church

| Need | Design choice |
|------|----------------|
| Speech intelligibility | Sealed 8″ midbass, flat 120 Hz–2.5 kHz; soft-dome HF for smooth consonants |
| Enough level | ~93 dB/W mid + ~50 W → ≈110 dB peak @1 m; place 1–2 units covering congregation |
| Reliability | Class-AB, conservative rails, thermal protection, Speakon + XLR, steel stand |
| “Super quality” | Scan-Speak / Seas-class mid & soft dome (or B&C pro option in BOM alt), film caps, metal-film R |
| Single cabinet | One powered box on stand — no passive XO losses |

**Coverage note:** For a full 300-seat main system, plan **two CAMS-1** (L/R) or one CAMS-1 as center vocal fill under a main PA. One unit alone is excellent for chapels / mid-size halls when placed properly (see `docs/placement-spl.md`).

---

## Folder map

| Path | Contents |
|------|----------|
| [`bom/MASTER_BOM.csv`](bom/MASTER_BOM.csv) | Every part to order (electronics + wood + stand + hardware) |
| [`bom/BOM_electronics.csv`](bom/BOM_electronics.csv) | Amps, XO, PSU, connectors |
| [`electronics/COMPONENTS_COMPLETE.csv`](electronics/COMPONENTS_COMPLETE.csv) | **Exact PCB parts with MPNs** (like lm3886 mid BOM) |
| [`kicad/`](kicad/) | **KiCad schematics** — root, XO@2.5k, dual LM3886, input/PSU |
| [`spice/cams1_full_chain.cir`](spice/cams1_full_chain.cir) | Full bi-amp AC simulation |
| [`electronics/pcb/PCB_DESIGN_NOTES.md`](electronics/pcb/PCB_DESIGN_NOTES.md) | Gerber / layout rules |
| [`enclosure/`](enclosure/) | Cut list, drawings, CNC notes |
| [`stand/`](stand/) | Stand fabrication drawings & weld notes |
| [`docs/`](docs/) | Assembly SOP, QC, placement, safety |
| [`qc/`](qc/) | Factory test checklist & burn-in |

---

## Key specifications (Rev A target)

| Parameter | Value |
|-----------|--------|
| Type | Active 2-way, sealed, bi-amped |
| Drivers | 8″ midbass + 1″ silk dome |
| Crossover | LR4 electrical @ **2.5 kHz** (active) |
| Amp mid | LM3886, gain 21 (26 dB), ±28 V max / **±25 V** used |
| Amp HF | LM3886, gain 21 with −6 dB pad / level pot |
| Bandwidth (−6 dB) | ≈ 90 Hz – 18 kHz (sealed alignment) |
| Max SPL (1 m, peak) | ≈ **108–112 dB** (driver/amp limited) |
| Input | XLR / 6.35 mm combo, balanced |
| Mains | 100–240 V IEC with fused inlet (use correct transformer tap) |
| Cabinet (ext.) | **300 × 500 × 320 mm** (W×H×D), 18–25 mm birch ply |
| Weight (speaker) | ≈ 14–16 kg |
| Stand height | 1200–1800 mm adjustable |
| Stand base | Ø450 mm weighted plate or tripod, tip-resistant |

**VERIFY** all driver cutouts, transformer VA, and mains wiring against datasheets and local electrical code before production.

---

## Manufacturing sequence (summary)

1. Order BOM (long-lead: drivers, transformer, Speakon, heatsinks).  
2. Cut / CNC enclosure panels; machine stand steel.  
3. Assemble / wire electronics (XO + dual LM3886 + PSU) on rear amp plate.  
4. Glue cabinet; install drivers, damping, grille.  
5. Mount amp plate; QC electrical (see `qc/`).  
6. Powder-coat stand; assemble pole + base.  
7. System burn-in + FR / THD spot check.  
8. Pack speaker + stand + IEC cable + manual.

Detail SOPs: [`docs/assembly-sop.md`](docs/assembly-sop.md).

---

## Related project modules (reuse)

- Mid amp topology: [`../lm3886-poweramp/`](../lm3886-poweramp/)  
- Active XO calculator: [`../active-crossover/calculator/calculator.py`](../active-crossover/calculator/calculator.py) — use `2500` Hz for this product  
- Measurement: [`../measurement/`](../measurement/)  
- Generic single-mid notes: [`../single-mid/`](../single-mid/)
