Vented Specialist

B & C BAC4CXN36AB

Best box: 1.5 L bass reflex tuned to 92.5 Hz · F3 123.6 Hz

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Comparable 4.0" Drivers

Drivers with similar piston area, resonance and Qts — useful alternatives when the B & C BAC4CXN36AB does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.

B & C

BAC4CXN36BB

4.0" · Fs 99.0 Hz · Qts 0.72 · Vas 1.9 L

FaitalPRO

4FE35 4" Professional Woofer 4 Ohm

4.0" · Fs 100.0 Hz · Qts 0.73 · Vas 2.0 L

SICA

4E11CS-8

4.0" · Fs 98.0 Hz · Qts 0.7 · Vas 2.1 L

FaitalPRO

4FE35-4F

4.0" · Fs 100.0 Hz · Qts 0.73 · Vas 2.4 L

FaitalPRO

4FE32 4" Neodymium Professional Woofer 16 Ohm

4.0" · Fs 100.0 Hz · Qts 0.8 · Vas 1.7 L

B&C Speakers

B&C 4CXN36 4" Professional Coaxial Speaker 70 x 70 8 Ohm

4.0" · Fs 94.0 Hz · Qts 0.76 · Vas 2.0 L

Compare them in the same box → Browse all 4.0" drivers → All B & C drivers →

⚠️ Engineering Notice for Builders

The textbook alignment (1.5 L at 84.1 Hz) would need a 51.9 cm port; the recommendation is retuned to 1.5 L at 92.5 Hz so the port can be built.

Recommended Bass Reflex (Vented)

PORT BUILDABLE

Net Box Volume (Vb)	1.5 Liters
Tuning Frequency (Fb)	92.5 Hz
F3 (-3 dB Cutoff)	123.6 Hz
F6 / F10 Extension	103.4 Hz / 81.0 Hz
Port Inner Diameter	Ø 5.0 cm
Port Physical Length	42.3 cm
First Pipe Resonance	407.0 Hz
Estimated MOL @ F3	106.4 dB SPL

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Sealed (Acoustic Suspension) — compromise

SUITS INFINITE / OPEN BAFFLE

With Qts 0.72 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.018; for a flat response this driver is better used on an infinite (IB) or open baffle.

Net Box Volume (Vb)	1.9 Liters
System Q (Qtc)	1.018 (above Butterworth: Qtc cannot fall below Qts (0.72))
System Resonance (Fc)	140.0 Hz
F3 (-3 dB Cutoff)	117.8 Hz
F6 / F10 Extension	97.1 Hz / 77.7 Hz
Air Spring Linearity	High (Zero port compression)

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Thiele/Small Parameters

Resonance (Fs)	99.0 Hz
Total Q (Qts)	0.72
Electrical Q (Qes)	0.761
Mechanical Q (Qms)	13.5

Equivalent Volume (Vas)	1.9 Liters
Diaphragm Area (Sd)	56.0 cm²
DC Resistance (Re)	5.5 Ω
Efficiency Bandwidth Product (EBP)	130.2

Linear Excursion (Xmax)	4.0 mm
Thermal Power (Pe)	100.0 W
Nominal Diameter	4.0"
Catalog Source	Load Forge catalog (manufacturer datasheets and retailer listings)

Frequently Asked Questions

What is the recommended ported (bass reflex) box volume for B & C BAC4CXN36AB?

Load Forge's calculated alignment puts B & C BAC4CXN36AB in a 1.5 liter vented enclosure tuned to 92.5 Hz, reaching an F3 cutoff of approximately 123.6 Hz.

Can B & C BAC4CXN36AB be used in a sealed box?

Yes. In a sealed (acoustic suspension) enclosure of 1.9 liters with a Qtc of 1.018 (above Butterworth: Qtc cannot fall below Qts (0.72)), the system exhibits an F3 of 117.8 Hz.

What port dimensions should be used for B & C BAC4CXN36AB to avoid port chuffing?

Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 42.3 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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