Wolfram Audio CU-6.5
Best box: 3.1 L bass reflex tuned to 58.0 Hz · F3 54.1 Hz
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Comparable 6.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Wolfram Audio CU-6.5 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 (1.8 L at 58.0 Hz) would need a 174.9 cm port; the recommendation is retuned to 3.1 L at 58.0 Hz so the port can be built.
- Port length (99.5 cm) exceeds a straight internal run; use an elbow bend, slotted vent or 3D folded duct to fit the enclosure.
Recommended Bass Reflex (Vented)
PORT NEEDS ELBOW / 3D| Net Box Volume (Vb) | 3.1 Liters |
| Tuning Frequency (Fb) | 58.0 Hz |
| F3 (-3 dB Cutoff) | 54.1 Hz |
| F6 / F10 Extension | 49.6 Hz / 44.6 Hz |
| Port Inner Diameter | Ø 6.8 cm |
| Port Physical Length | 99.5 cm |
| First Pipe Resonance | 173.0 Hz |
| Estimated MOL @ F3 | 106.5 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 0.8 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 108.8 Hz |
| F3 (-3 dB Cutoff) | 106.4 Hz |
| F6 / F10 Extension | 81.3 Hz / 61.6 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 49.5 Hz |
| Total Q (Qts) | 0.32 |
| Electrical Q (Qes) | 0.358 |
| Mechanical Q (Qms) | 3.0 |
| Equivalent Volume (Vas) | 3.1 Liters |
| Diaphragm Area (Sd) | 132.0 cm² |
| DC Resistance (Re) | 2.0 Ω |
| Efficiency Bandwidth Product (EBP) | 138.2 |
| Linear Excursion (Xmax) | 12.0 mm |
| Thermal Power (Pe) | 500.0 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 Wolfram Audio CU-6.5?
Load Forge's calculated alignment puts Wolfram Audio CU-6.5 in a 3.1 liter vented enclosure tuned to 58.0 Hz, reaching an F3 cutoff of approximately 54.1 Hz.
Can Wolfram Audio CU-6.5 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.8 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 106.4 Hz.
What port dimensions should be used for Wolfram Audio CU-6.5 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 6.8 cm with a length of 99.5 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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