SICA 18 S 4 CP (Copy)
Best box: 73.0 L sealed · Fc 63.5 Hz · F3 64.6 Hz
Open and tweak this box live ↗
Will it fit your requirements?
Check the SICA 18 S 4 CP (Copy) against your space and targets — instant, no sign-up.
Free, no sign-up to simulate · a free account saves your design
Comparable 18.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the SICA 18 S 4 CP (Copy) does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- Straight vent would be 928.8 cm long: not physically buildable as a simple tube. Use a passive radiator, a folded slot port or model a 3D folded duct in Load Forge Studio.
- Large enclosure volume (165.9 L) requires extensive internal matrix bracing to prevent panel resonance.
Textbook Bass Reflex — not recommended
PORT NOT BUILDABLE| Net Box Volume (Vb) | 165.9 Liters |
| Tuning Frequency (Fb) | 35.7 Hz |
| F3 (-3 dB Cutoff) | 35.1 Hz |
| F6 / F10 Extension | 31.1 Hz / 27.3 Hz |
| Port Inner Diameter | Ø 94.6 cm |
| Port Physical Length | 928.8 cm |
| First Pipe Resonance | 19.0 Hz |
| Estimated MOL @ F3 | 122.1 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 73.0 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 63.5 Hz |
| F3 (-3 dB Cutoff) | 64.6 Hz |
| F6 / F10 Extension | 48.6 Hz / 36.6 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 33.0 Hz |
| Total Q (Qts) | 0.35 |
| Electrical Q (Qes) | 0.384 |
| Mechanical Q (Qms) | 3.94 |
| Equivalent Volume (Vas) | 225.0 Liters |
| Diaphragm Area (Sd) | 1164.2 cm² |
| DC Resistance (Re) | 5.2 Ω |
| Efficiency Bandwidth Product (EBP) | 85.9 |
| Linear Excursion (Xmax) | 463.0 mm |
| Thermal Power (Pe) | 1200.0 W |
| Nominal Diameter | 18.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for SICA 18 S 4 CP (Copy)?
A simple ported box is not recommended for SICA 18 S 4 CP (Copy): the textbook alignment (165.9 liters tuned to 35.7 Hz) needs a 928.8 cm port, and no nearby retune stays buildable without a bass hump. A sealed box, a passive radiator or a folded duct is the practical choice.
Can SICA 18 S 4 CP (Copy) be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 73.0 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 64.6 Hz.
What port dimensions should be used for SICA 18 S 4 CP (Copy) to avoid port chuffing?
A straight 94.6 cm port would need 928.8 cm of length, which does not fit a practical cabinet. Use a passive radiator or a folded/3D duct instead of a straight tube.
Shareable Acoustic Card for Forums & Social Media
Embed this design card on DIYAudio, AVSForum, Reddit, or Facebook. It shows the calculated F3, MOL (when the power rating is published) and box parameters.
Not sure if 18 S 4 CP (Copy) fits your physical space?
Don't force a driver into the wrong box. Use Bass Match to calculate which of 8,000+ catalog drivers delivers the highest SPL, lowest F3, and cleanest port air velocity for your exact trunk or room dimensions.
Run Bass Match for Your Space