subsim
21" Tapped Horn
Specifications
| Topology | tapped horn |
|---|---|
| Build complexity | complex |
| Net volume | 280 L |
| Dimensions (H×W×D) | 1120 × 700 × 780 mm |
| Footprint | 5460 cm² |
| Weight | 78 kg |
| F3 | 30 Hz |
| F6 | 23 Hz |
| Max SPL | 141 dB |
| Impedance minimum | 4.9 Ω |
| Recommended crossover | 85 Hz |
| Recommended power | 1500 W |
| Power handling (AES) | 1700 W |
| Power handling (program) | 3400 W |
| Max port velocity | 22 m/s |
| Output density | 116.5 dB/size |
| Plywood sheets | 3× 2440×1220 mm |
| Connectors | speakON NL4 |
Drivers (1)
| Model | Format | Impedance | Fs | Detail | Pe | Sensitivity |
|---|---|---|---|---|---|---|
| B&C 21DS115 | 21" | 8 Ω | 34 Hz | Qts 0.27 · Vas 204 L · Xmax 16.5 mm | 1700 W | 99 dB |
Measurements / Simulations
Images
Sources
- design.txt · hornresp
Notes
Build notes
Sample data: values are illustrative, not measured.
Large-format 21“ tapped horn achieving sub-30 Hz extension at very high output levels. The folded horn path keeps depth manageable given the cabinet volume.
Key design choices
- Horn mouth area: ~4000 cm²
- Horn throat area matched to driver Sd (1620 cm²)
- Horn expansion ratio: ~1.45
- 18 mm birch ply throughout; 21 mm for baffle
- Internal bracing every 280 mm
Tuning
Optimised for flat response from 30 Hz upward. Low-pass at 80-100 Hz recommended. This box is heavy. Budget for a dolly or two-person carry.