Coast Buyouts 132141B 4" Paper Cone Speaker 8 Ohm
Best box: 0.48 L sealed · Fc 435.7 Hz · F3 379.6 Hz
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Comparable 4.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Coast Buyouts 132141B 4" Paper Cone Speaker 8 Ohm 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
- Limited linear excursion (Xmax: 1.0 mm); set a high-pass subsonic filter at 25–30 Hz when driven with high power.
Textbook Bass Reflex — not recommended (22.1 dB bass hump)
PORT BUILDABLE| Net Box Volume (Vb) | 1.5 Liters |
| Tuning Frequency (Fb) | 261.9 Hz |
| F3 (-3 dB Cutoff) | 333.4 Hz |
| F6 / F10 Extension | 303.5 Hz / 201.4 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 2.1 cm |
| First Pipe Resonance | 8017.0 Hz |
| Estimated MOL @ F3 | 104.6 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 3.375 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 4.773; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 0.48 Liters |
| System Q (Qtc) | 4.773 (above Butterworth: Qtc cannot fall below Qts (3.38)) |
| System Resonance (Fc) | 435.7 Hz |
| F3 (-3 dB Cutoff) | 379.6 Hz |
| F6 / F10 Extension | 354.7 Hz / 320.9 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 308.1 Hz |
| Total Q (Qts) | 3.375 |
| Electrical Q (Qes) | 4.755 |
| Mechanical Q (Qms) | 11.63 |
| Equivalent Volume (Vas) | 0.5 Liters |
| Diaphragm Area (Sd) | 56.8 cm² |
| DC Resistance (Re) | 7.33 Ω |
| Efficiency Bandwidth Product (EBP) | 64.8 |
| Linear Excursion (Xmax) | 1.0 mm |
| Thermal Power (Pe) | 4.0 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 Coast Buyouts 132141B 4" Paper Cone Speaker 8 Ohm?
A simple ported box is not recommended for Coast Buyouts 132141B 4" Paper Cone Speaker 8 Ohm: the textbook alignment (1.5 liters tuned to 261.9 Hz) needs a 2.1 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 Coast Buyouts 132141B 4" Paper Cone Speaker 8 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.48 liters with a Qtc of 4.773 (above Butterworth: Qtc cannot fall below Qts (3.38)), the system exhibits an F3 of 379.6 Hz.
What port dimensions should be used for Coast Buyouts 132141B 4" Paper Cone Speaker 8 Ohm to avoid port chuffing?
A straight 5.0 cm port would need 2.1 cm of length, which does not fit a practical cabinet. Use a passive radiator or a folded/3D duct instead of a straight tube.
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