Goldwood GW-S650/4 6-1/2" Poly Cone Woofer 4 Ohm
Best box: 12.5 L bass reflex tuned to 46.8 Hz · F3 67.0 Hz
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Comparable 6.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Goldwood GW-S650/4 6-1/2" Poly Cone Woofer 4 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: 2.5 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) | 12.5 Liters |
| Tuning Frequency (Fb) | 46.8 Hz |
| F3 (-3 dB Cutoff) | 67.0 Hz |
| F6 / F10 Extension | 55.5 Hz / 42.6 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 17.9 cm |
| First Pipe Resonance | 960.0 Hz |
| Estimated MOL @ F3 | 101.0 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.71 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.004; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 15.6 Liters |
| System Q (Qtc) | 1.004 (above Butterworth: Qtc cannot fall below Qts (0.71)) |
| System Resonance (Fc) | 77.8 Hz |
| F3 (-3 dB Cutoff) | 65.2 Hz |
| F6 / F10 Extension | 53.7 Hz / 43.0 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 55.0 Hz |
| Total Q (Qts) | 0.71 |
| Electrical Q (Qes) | 0.874 |
| Mechanical Q (Qms) | 3.79 |
| Equivalent Volume (Vas) | 15.6 Liters |
| Diaphragm Area (Sd) | 139.7 cm² |
| DC Resistance (Re) | 3.7 Ω |
| Efficiency Bandwidth Product (EBP) | 63.0 |
| Linear Excursion (Xmax) | 2.5 mm |
| Thermal Power (Pe) | 80.0 W |
| Nominal Diameter | 6.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Goldwood GW-S650/4 6-1/2" Poly Cone Woofer 4 Ohm?
Load Forge's calculated alignment puts Goldwood GW-S650/4 6-1/2" Poly Cone Woofer 4 Ohm in a 12.5 liter vented enclosure tuned to 46.8 Hz, reaching an F3 cutoff of approximately 67.0 Hz.
Can Goldwood GW-S650/4 6-1/2" Poly Cone Woofer 4 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 15.6 liters with a Qtc of 1.004 (above Butterworth: Qtc cannot fall below Qts (0.71)), the system exhibits an F3 of 65.2 Hz.
What port dimensions should be used for Goldwood GW-S650/4 6-1/2" Poly Cone Woofer 4 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 17.9 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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