VAS Audio VAS-18-1700FC
Best box: 81.7 L bass reflex tuned to 45.8 Hz · F3 45.9 Hz
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Comparable 18.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the VAS Audio VAS-18-1700FC 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 (81.7 L at 41.6 Hz) would need a 52.3 cm port; the recommendation is retuned to 81.7 L at 45.8 Hz so the port can be built.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 81.7 Liters |
| Tuning Frequency (Fb) | 45.8 Hz |
| F3 (-3 dB Cutoff) | 45.9 Hz |
| F6 / F10 Extension | 40.8 Hz / 35.8 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | 40.6 cm |
| First Pipe Resonance | 423.0 Hz |
| Estimated MOL @ F3 | 124.2 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 38.2 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 76.1 Hz |
| F3 (-3 dB Cutoff) | 77.5 Hz |
| F6 / F10 Extension | 58.5 Hz / 44.1 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 33.0 Hz |
| Total Q (Qts) | 0.295 |
| Electrical Q (Qes) | 0.301 |
| Mechanical Q (Qms) | 14.3 |
| Equivalent Volume (Vas) | 181.0 Liters |
| Diaphragm Area (Sd) | 1225.0 cm² |
| DC Resistance (Re) | 5.4 Ω |
| Efficiency Bandwidth Product (EBP) | 109.6 |
| Linear Excursion (Xmax) | 13.5 mm |
| Thermal Power (Pe) | 1700.0 W |
| Nominal Diameter | 18.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for VAS Audio VAS-18-1700FC?
Load Forge's calculated alignment puts VAS Audio VAS-18-1700FC in a 81.7 liter vented enclosure tuned to 45.8 Hz, reaching an F3 cutoff of approximately 45.9 Hz.
Can VAS Audio VAS-18-1700FC be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 38.2 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 77.5 Hz.
What port dimensions should be used for VAS Audio VAS-18-1700FC to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 20.0 cm with a length of 40.6 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
Embed this design card on DIYAudio, AVSForum, Reddit, or Facebook. It shows the calculated F3, MOL (when the power rating is published) and box parameters.
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