SICA LP459.75/1790T-4
Best box: 522.8 L bass reflex tuned to 27.5 Hz · F3 25.2 Hz
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Comparable 18.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the SICA LP459.75/1790T-4 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
- Large enclosure volume (522.8 L) requires extensive internal matrix bracing to prevent panel resonance.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 522.8 Liters |
| Tuning Frequency (Fb) | 27.5 Hz |
| F3 (-3 dB Cutoff) | 25.2 Hz |
| F6 / F10 Extension | 22.9 Hz / 20.5 Hz |
| Port Inner Diameter | Ø 15.0 cm |
| Port Physical Length | 2.7 cm |
| First Pipe Resonance | 6436.0 Hz |
| Estimated MOL @ F3 | 115.2 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 230.6 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 46.8 Hz |
| F3 (-3 dB Cutoff) | 49.3 Hz |
| F6 / F10 Extension | 36.6 Hz / 27.4 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 30.6 Hz |
| Total Q (Qts) | 0.43 |
| Electrical Q (Qes) | 0.455 |
| Mechanical Q (Qms) | 7.69 |
| Equivalent Volume (Vas) | 392.8 Liters |
| Diaphragm Area (Sd) | 1164.2 cm² |
| DC Resistance (Re) | 3.1 Ω |
| Efficiency Bandwidth Product (EBP) | 67.2 |
| Linear Excursion (Xmax) | 5.0 mm |
| Thermal Power (Pe) | 400.0 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 LP459.75/1790T-4?
Load Forge's calculated alignment puts SICA LP459.75/1790T-4 in a 522.8 liter vented enclosure tuned to 27.5 Hz, reaching an F3 cutoff of approximately 25.2 Hz.
Can SICA LP459.75/1790T-4 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 230.6 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 49.3 Hz.
What port dimensions should be used for SICA LP459.75/1790T-4 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 15.0 cm with a length of 2.7 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
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.
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