Passive Radiator / Folded Port

JBL 2203A

Best box: 16.3 L sealed · Fc 78.4 Hz · F3 79.6 Hz

Predicted SPL response of the JBL 2203A in the recommended 16.3 L sealed box versus the alternative — open it in the simulator Open and tweak this box live ↗

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⚠️ Engineering Notice for Builders

  • Straight vent would be 866.2 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.

Textbook Bass Reflex — not recommended

PORT NOT BUILDABLE
Net Box Volume (Vb) 21.2 Liters
Tuning Frequency (Fb) 39.4 Hz
F3 (-3 dB Cutoff) 61.0 Hz
F6 / F10 Extension 48.4 Hz / 39.2 Hz
Port Inner Diameter Ø 35.3 cm
Port Physical Length 866.2 cm
First Pipe Resonance 20.0 Hz
Estimated MOL @ F3 108.8 dB SPL
⚠️ Port feasibility: a straight tube would need 866.2 cm and cannot fit in a practical cabinet, and no nearby retune stays buildable without a bass hump. Prefer the sealed alignment, a passive radiator, or a 3D folded duct in Load Forge Studio.
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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) 78.4 Hz
F3 (-3 dB Cutoff) 79.6 Hz
F6 / F10 Extension 59.5 Hz / 44.6 Hz
Air Spring Linearity High (Zero port compression)
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Thiele/Small Parameters

Resonance (Fs) 16.0 Hz
Total Q (Qts) 0.14
Electrical Q (Qes) 0.143
Mechanical Q (Qms) 6.0
Equivalent Volume (Vas) 399.3 Liters
Diaphragm Area (Sd) 527.0 cm²
DC Resistance (Re) 6.3 Ω
Efficiency Bandwidth Product (EBP) 111.6
Linear Excursion (Xmax) 129.0 mm
Thermal Power (Pe) 100.0 W
Nominal Diameter 12.0"
Catalog Source Load Forge catalog (manufacturer datasheets and retailer listings)

Frequently Asked Questions

What is the recommended ported (bass reflex) box volume for JBL 2203A?

A simple ported box is not recommended for JBL 2203A: the textbook alignment (21.2 liters tuned to 39.4 Hz) needs a 866.2 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 JBL 2203A 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 79.6 Hz.

What port dimensions should be used for JBL 2203A to avoid port chuffing?

A straight 35.3 cm port would need 866.2 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.

JBL 2203A Enclosure Card
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