Coast Buyouts O-14 3-1/2" Paper Cone Full-Range Speaker 8 Ohms
Best box: 3.0 L bass reflex tuned to 82.1 Hz · F3 131.4 Hz
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Comparable 3.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Coast Buyouts O-14 3-1/2" Paper Cone Full-Range Speaker 8 Ohms 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 (1.5 L at 117.3 Hz) would need a 24.9 cm port; the recommendation is retuned to 3.0 L at 82.1 Hz so the port can be built.
- Limited linear excursion (Xmax: 1.0 mm); set a high-pass subsonic filter at 25–30 Hz when driven with high power.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 3.0 Liters |
| Tuning Frequency (Fb) | 82.1 Hz |
| F3 (-3 dB Cutoff) | 131.4 Hz |
| F6 / F10 Extension | 110.1 Hz / 64.7 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 25.5 cm |
| First Pipe Resonance | 674.0 Hz |
| Estimated MOL @ F3 | 92.1 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 1.46 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 2.065; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 1.2 Liters |
| System Q (Qtc) | 2.065 (above Butterworth: Qtc cannot fall below Qts (1.46)) |
| System Resonance (Fc) | 195.2 Hz |
| F3 (-3 dB Cutoff) | 161.5 Hz |
| F6 / F10 Extension | 143.4 Hz / 122.5 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 138.0 Hz |
| Total Q (Qts) | 1.46 |
| Electrical Q (Qes) | 1.98 |
| Mechanical Q (Qms) | 5.56 |
| Equivalent Volume (Vas) | 1.2 Liters |
| Diaphragm Area (Sd) | 38.4 cm² |
| DC Resistance (Re) | 7.2 Ω |
| Efficiency Bandwidth Product (EBP) | 69.7 |
| Linear Excursion (Xmax) | 1.0 mm |
| Thermal Power (Pe) | 5.0 W |
| Nominal Diameter | 3.5" |
| 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 O-14 3-1/2" Paper Cone Full-Range Speaker 8 Ohms?
Load Forge's calculated alignment puts Coast Buyouts O-14 3-1/2" Paper Cone Full-Range Speaker 8 Ohms in a 3.0 liter vented enclosure tuned to 82.1 Hz, reaching an F3 cutoff of approximately 131.4 Hz.
Can Coast Buyouts O-14 3-1/2" Paper Cone Full-Range Speaker 8 Ohms be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 1.2 liters with a Qtc of 2.065 (above Butterworth: Qtc cannot fall below Qts (1.46)), the system exhibits an F3 of 161.5 Hz.
What port dimensions should be used for Coast Buyouts O-14 3-1/2" Paper Cone Full-Range Speaker 8 Ohms to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 25.5 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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