B2 Audio 39556
Best box: 62.1 L bass reflex tuned to 27.9 Hz · F3 24.3 Hz
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Comparable 12.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the B2 Audio 39556 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 (35.5 L at 22.3 Hz) would need a 199.4 cm port; the recommendation is retuned to 62.1 L at 27.9 Hz so the port can be built.
- Xmax is not published, so the port size is an empirical estimate (area ≥ 12 in² per ft³ of net volume, minimum by driver size), not a displacement calculation. Check air velocity in Load Forge Studio.
- Port length (98.9 cm) exceeds a straight internal run; use an elbow bend, slotted vent or 3D folded duct to fit the enclosure.
Recommended Bass Reflex (Vented)
PORT NEEDS ELBOW / 3D| Net Box Volume (Vb) | 62.1 Liters |
| Tuning Frequency (Fb) | 27.9 Hz |
| F3 (-3 dB Cutoff) | 24.3 Hz |
| F6 / F10 Extension | 22.7 Hz / 20.7 Hz |
| Port Inner Diameter ESTIMATED | Ø 15.0 cm |
| Port Physical Length | 98.9 cm |
| First Pipe Resonance | 174.0 Hz |
| Estimated MOL @ F3 | 120.8 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 21.9 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 40.1 Hz |
| F3 (-3 dB Cutoff) | 41.2 Hz |
| F6 / F10 Extension | 31.2 Hz / 23.6 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 28.0 Hz |
| Total Q (Qts) | 0.49 |
| Electrical Q (Qes) | 0.539 |
| Mechanical Q (Qms) | 5.38 |
| Equivalent Volume (Vas) | 23.7 Liters |
| Diaphragm Area (Sd) | 472.6 cm² |
| DC Resistance (Re) | 0.75 Ω |
| Efficiency Bandwidth Product (EBP) | 51.9 |
| Linear Excursion (Xmax) | N/A mm |
| Thermal Power (Pe) | 10000.0 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 B2 Audio 39556?
Load Forge's calculated alignment puts B2 Audio 39556 in a 62.1 liter vented enclosure tuned to 27.9 Hz, reaching an F3 cutoff of approximately 24.3 Hz.
Can B2 Audio 39556 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 21.9 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 41.2 Hz.
What port dimensions should be used for B2 Audio 39556 to avoid port chuffing?
Xmax is not published for B2 Audio 39556, so the port is an empirical estimate: a 15.0 cm diameter with a length of 98.9 cm (area at least 12 in² per ft³ of net volume). Check the air velocity at your power level in Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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