Sealed Specialist

Stereo Integrity HT-18 v3 D2

Best box: 423.0 L bass reflex tuned to 15.1 Hz · F3 14.4 Hz

Predicted SPL response of the Stereo Integrity HT-18 v3 D2 in the recommended 423.0 L bass reflex box versus the alternative — open it in the simulator Open and tweak this box live ↗

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⚠️ Engineering Notice for Builders

  • Large enclosure volume (423.0 L) requires extensive internal matrix bracing to prevent panel resonance.

Recommended Bass Reflex (Vented)

PORT BUILDABLE
Net Box Volume (Vb) 423.0 Liters
Tuning Frequency (Fb) 15.1 Hz
F3 (-3 dB Cutoff) 14.4 Hz
F6 / F10 Extension 12.8 Hz / 11.4 Hz
Port Inner Diameter Ø 15.0 cm
Port Physical Length 44.2 cm
First Pipe Resonance 389.0 Hz
Estimated MOL @ F3 112.7 dB SPL
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Recommended Sealed (Acoustic Suspension)

MAX TRANSIENT DAMPING
Net Box Volume (Vb) 185.4 Liters
System Q (Qtc) 0.707 (Butterworth)
System Resonance (Fc) 27.3 Hz
F3 (-3 dB Cutoff) 28.1 Hz
F6 / F10 Extension 21.1 Hz / 15.9 Hz
Air Spring Linearity High (Zero port compression)
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Thiele/Small Parameters

Resonance (Fs) 16.5 Hz
Total Q (Qts) 0.42
Electrical Q (Qes) 0.451
Mechanical Q (Qms) 6.2
Equivalent Volume (Vas) 340.0 Liters
Diaphragm Area (Sd) 1210.0 cm²
DC Resistance (Re) 3.6 Ω
Efficiency Bandwidth Product (EBP) 36.6
Linear Excursion (Xmax) 22.0 mm
Thermal Power (Pe) 750.0 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 Stereo Integrity HT-18 v3 D2?

Load Forge's calculated alignment puts Stereo Integrity HT-18 v3 D2 in a 423.0 liter vented enclosure tuned to 15.1 Hz, reaching an F3 cutoff of approximately 14.4 Hz.

Can Stereo Integrity HT-18 v3 D2 be used in a sealed box?

Yes. In a sealed (acoustic suspension) enclosure of 185.4 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 28.1 Hz.

What port dimensions should be used for Stereo Integrity HT-18 v3 D2 to avoid port chuffing?

Sized from cone displacement (Sd × Xmax), a minimum port diameter of 15.0 cm with a length of 44.2 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.

Stereo Integrity HT-18 v3 D2 Enclosure Card
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