Vented Specialist

Eighteen Sound 15NLW9401

Best box: 32.0 L bass reflex tuned to 73.1 Hz · F3 73.4 Hz

Predicted SPL response of the Eighteen Sound 15NLW9401 in the recommended 32.0 L bass reflex box versus the alternative — open it in the simulator Open and tweak this box live ↗

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Estimated retail 376.00 EUR · Check price & availability ↗

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⚠️ Engineering Notice for Builders

  • The textbook alignment (32.0 L at 58.5 Hz) would need a 71.7 cm port; the recommendation is retuned to 32.0 L at 73.1 Hz so the port can be built.

Recommended Bass Reflex (Vented)

PORT BUILDABLE
Net Box Volume (Vb) 32.0 Liters
Tuning Frequency (Fb) 73.1 Hz
F3 (-3 dB Cutoff) 73.4 Hz
F6 / F10 Extension 66.0 Hz / 58.1 Hz
Port Inner Diameter Ø 20.0 cm
Port Physical Length 40.8 cm
First Pipe Resonance 422.0 Hz
Estimated MOL @ F3 124.8 dB SPL
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Recommended Sealed (Acoustic Suspension)

MAX TRANSIENT DAMPING
Net Box Volume (Vb) 16.3 Liters
System Q (Qtc) 0.707 (Butterworth)
System Resonance (Fc) 108.6 Hz
F3 (-3 dB Cutoff) 104.5 Hz
F6 / F10 Extension 79.3 Hz / 59.8 Hz
Air Spring Linearity High (Zero port compression)
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Thiele/Small Parameters

Resonance (Fs) 40.0 Hz
Total Q (Qts) 0.25
Electrical Q (Qes) 0.261
Mechanical Q (Qms) 6.14
Equivalent Volume (Vas) 114.0 Liters
Diaphragm Area (Sd) 850.0 cm²
DC Resistance (Re) 2.8 Ω
Efficiency Bandwidth Product (EBP) 153.5
Linear Excursion (Xmax) 10.0 mm
Thermal Power (Pe) 1200.0 W
Nominal Diameter 15.0"
Catalog Source Load Forge catalog (manufacturer datasheets and retailer listings)

Frequently Asked Questions

What is the recommended ported (bass reflex) box volume for Eighteen Sound 15NLW9401?

Load Forge's calculated alignment puts Eighteen Sound 15NLW9401 in a 32.0 liter vented enclosure tuned to 73.1 Hz, reaching an F3 cutoff of approximately 73.4 Hz.

Can Eighteen Sound 15NLW9401 be used in a sealed box?

Yes. In a sealed (acoustic suspension) enclosure of 16.3 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 104.5 Hz.

What port dimensions should be used for Eighteen Sound 15NLW9401 to avoid port chuffing?

Sized from cone displacement (Sd × Xmax), a minimum port diameter of 20.0 cm with a length of 40.8 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.

Eighteen Sound 15NLW9401 Enclosure Card
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