GRS 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8
Best box: 9.3 L bass reflex tuned to 48.4 Hz · F3 44.6 Hz
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Comparable 5.25" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the GRS 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8 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: 2.0 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) | 9.3 Liters |
| Tuning Frequency (Fb) | 48.4 Hz |
| F3 (-3 dB Cutoff) | 44.6 Hz |
| F6 / F10 Extension | 40.3 Hz / 36.1 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 23.4 cm |
| First Pipe Resonance | 734.0 Hz |
| Estimated MOL @ F3 | 94.4 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 4.1 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 87.1 Hz |
| F3 (-3 dB Cutoff) | 87.6 Hz |
| F6 / F10 Extension | 65.9 Hz / 49.6 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 55.0 Hz |
| Total Q (Qts) | 0.44 |
| Electrical Q (Qes) | 0.509 |
| Mechanical Q (Qms) | 3.26 |
| Equivalent Volume (Vas) | 6.5 Liters |
| Diaphragm Area (Sd) | 80.0 cm² |
| DC Resistance (Re) | 6.0 Ω |
| Efficiency Bandwidth Product (EBP) | 108.1 |
| Linear Excursion (Xmax) | 2.0 mm |
| Thermal Power (Pe) | 35.0 W |
| Nominal Diameter | 5.25" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for GRS 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8?
Load Forge's calculated alignment puts GRS 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8 in a 9.3 liter vented enclosure tuned to 48.4 Hz, reaching an F3 cutoff of approximately 44.6 Hz.
Can GRS 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 4.1 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 87.6 Hz.
What port dimensions should be used for GRS 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 23.4 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
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Not sure if 5-1/4" Woofer Surface Mount Poly Cone 8 Ohm 5SMP-8 fits your physical space?
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