Coast Buyouts EAS1212D131D 3" X 5" Full-Range Speaker 8 Ohm
Best box: 4.0 L bass reflex tuned to 104.8 Hz · F3 122.8 Hz
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Comparable 3.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Coast Buyouts EAS1212D131D 3" X 5" Full-Range 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
- The textbook alignment (2.0 L at 116.4 Hz) would need a 18.1 cm port; the recommendation is retuned to 4.0 L at 104.8 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) | 4.0 Liters |
| Tuning Frequency (Fb) | 104.8 Hz |
| F3 (-3 dB Cutoff) | 122.8 Hz |
| F6 / F10 Extension | 87.8 Hz / 79.4 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 9.8 cm |
| First Pipe Resonance | 1751.0 Hz |
| Estimated MOL @ F3 | 97.8 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 1.334 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.887; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 2.5 Liters |
| System Q (Qtc) | 1.887 (above Butterworth: Qtc cannot fall below Qts (1.33)) |
| System Resonance (Fc) | 193.6 Hz |
| F3 (-3 dB Cutoff) | 140.3 Hz |
| F6 / F10 Extension | 122.6 Hz / 103.1 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 136.9 Hz |
| Total Q (Qts) | 1.334 |
| Electrical Q (Qes) | 2.002 |
| Mechanical Q (Qms) | 4.0 |
| Equivalent Volume (Vas) | 2.5 Liters |
| Diaphragm Area (Sd) | 40.7 cm² |
| DC Resistance (Re) | 6.37 Ω |
| Efficiency Bandwidth Product (EBP) | 68.4 |
| Linear Excursion (Xmax) | 1.0 mm |
| Thermal Power (Pe) | 10.0 W |
| Nominal Diameter | 3.0" |
| 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 EAS1212D131D 3" X 5" Full-Range Speaker 8 Ohm?
Load Forge's calculated alignment puts Coast Buyouts EAS1212D131D 3" X 5" Full-Range Speaker 8 Ohm in a 4.0 liter vented enclosure tuned to 104.8 Hz, reaching an F3 cutoff of approximately 122.8 Hz.
Can Coast Buyouts EAS1212D131D 3" X 5" Full-Range Speaker 8 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 2.5 liters with a Qtc of 1.887 (above Butterworth: Qtc cannot fall below Qts (1.33)), the system exhibits an F3 of 140.3 Hz.
What port dimensions should be used for Coast Buyouts EAS1212D131D 3" X 5" Full-Range Speaker 8 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 9.8 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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