Scan-Speak 18W/4545-03
Best box: 12.4 L bass reflex tuned to 43.7 Hz · F3 46.6 Hz
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Comparable 7.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Scan-Speak 18W/4545-03 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
- The textbook alignment (12.4 L at 41.6 Hz) would need a 45.9 cm port; the recommendation is retuned to 12.4 L at 43.7 Hz so the port can be built.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 12.4 Liters |
| Tuning Frequency (Fb) | 43.7 Hz |
| F3 (-3 dB Cutoff) | 46.6 Hz |
| F6 / F10 Extension | 40.6 Hz / 35.1 Hz |
| Port Inner Diameter | Ø 6.8 cm |
| Port Physical Length | 41.1 cm |
| First Pipe Resonance | 418.0 Hz |
| Estimated MOL @ F3 | 102.5 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 6.0 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 78.4 Hz |
| F3 (-3 dB Cutoff) | 80.2 Hz |
| F6 / F10 Extension | 60.2 Hz / 45.3 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 30.5 Hz |
| Total Q (Qts) | 0.27 |
| Electrical Q (Qes) | 0.318 |
| Mechanical Q (Qms) | 1.8 |
| Equivalent Volume (Vas) | 35.4 Liters |
| Diaphragm Area (Sd) | 150.0 cm² |
| DC Resistance (Re) | 3.5 Ω |
| Efficiency Bandwidth Product (EBP) | 96.0 |
| Linear Excursion (Xmax) | 10.0 mm |
| Thermal Power (Pe) | 80.0 W |
| Nominal Diameter | 7.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Scan-Speak 18W/4545-03?
Load Forge's calculated alignment puts Scan-Speak 18W/4545-03 in a 12.4 liter vented enclosure tuned to 43.7 Hz, reaching an F3 cutoff of approximately 46.6 Hz.
Can Scan-Speak 18W/4545-03 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 6.0 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 80.2 Hz.
What port dimensions should be used for Scan-Speak 18W/4545-03 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 6.8 cm with a length of 41.1 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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