Visaton FR 9.15 - 4 Ohm
Best box: 4.6 L bass reflex tuned to 61.2 Hz · F3 133.5 Hz
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Comparable 5.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Visaton FR 9.15 - 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
- The textbook alignment (2.3 L at 102.0 Hz) would need a 21.0 cm port; the recommendation is retuned to 4.6 L at 61.2 Hz so the port can be built.
- Limited linear excursion (Xmax: 1.5 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) | 4.6 Liters |
| Tuning Frequency (Fb) | 61.2 Hz |
| F3 (-3 dB Cutoff) | 133.5 Hz |
| F6 / F10 Extension | 118.5 Hz / 99.7 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 30.6 cm |
| First Pipe Resonance | 562.0 Hz |
| Estimated MOL @ F3 | 99.9 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 1.82 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 2.574; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 2.9 Liters |
| System Q (Qtc) | 2.574 (above Butterworth: Qtc cannot fall below Qts (1.82)) |
| System Resonance (Fc) | 169.7 Hz |
| F3 (-3 dB Cutoff) | 147.7 Hz |
| F6 / F10 Extension | 133.5 Hz / 116.3 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 120.0 Hz |
| Total Q (Qts) | 1.82 |
| Electrical Q (Qes) | 2.288 |
| Mechanical Q (Qms) | 8.9 |
| Equivalent Volume (Vas) | 2.9 Liters |
| Diaphragm Area (Sd) | 79.0 cm² |
| DC Resistance (Re) | 3.5 Ω |
| Efficiency Bandwidth Product (EBP) | 52.5 |
| Linear Excursion (Xmax) | 1.5 mm |
| Thermal Power (Pe) | 15.0 W |
| Nominal Diameter | 5.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Visaton FR 9.15 - 4 Ohm?
Load Forge's calculated alignment puts Visaton FR 9.15 - 4 Ohm in a 4.6 liter vented enclosure tuned to 61.2 Hz, reaching an F3 cutoff of approximately 133.5 Hz.
Can Visaton FR 9.15 - 4 Ohm be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 2.9 liters with a Qtc of 2.574 (above Butterworth: Qtc cannot fall below Qts (1.82)), the system exhibits an F3 of 147.7 Hz.
What port dimensions should be used for Visaton FR 9.15 - 4 Ohm to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 30.6 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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