Visaton SL 87 WP 4 OHM
Best box: 1.9 L bass reflex tuned to 137.7 Hz · F3 232.1 Hz
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Comparable 3.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Visaton SL 87 WP 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 (1.5 L at 229.5 Hz) would need a 3.9 cm port; the recommendation is retuned to 1.9 L at 137.7 Hz so the port can be built.
- Xmax is not published, so the port size is an empirical estimate (area ≥ 12 in² per ft³ of net volume, minimum by driver size), not a displacement calculation. Check air velocity in Load Forge Studio.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 1.9 Liters |
| Tuning Frequency (Fb) | 137.7 Hz |
| F3 (-3 dB Cutoff) | 232.1 Hz |
| F6 / F10 Extension | 121.6 Hz / 114.0 Hz |
| Port Inner Diameter ESTIMATED | Ø 5.0 cm |
| Port Physical Length | 12.8 cm |
| First Pipe Resonance | 1348.0 Hz |
| Estimated MOL @ F3 | 103.7 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 2.16 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 3.055; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 0.37 Liters |
| System Q (Qtc) | 3.055 (above Butterworth: Qtc cannot fall below Qts (2.16)) |
| System Resonance (Fc) | 381.8 Hz |
| F3 (-3 dB Cutoff) | 321.4 Hz |
| F6 / F10 Extension | 286.0 Hz / 244.9 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 270.0 Hz |
| Total Q (Qts) | 2.16 |
| Electrical Q (Qes) | 3.142 |
| Mechanical Q (Qms) | 6.91 |
| Equivalent Volume (Vas) | 0.4 Liters |
| Diaphragm Area (Sd) | 41.0 cm² |
| DC Resistance (Re) | 3.8 Ω |
| Efficiency Bandwidth Product (EBP) | 85.9 |
| Linear Excursion (Xmax) | N/A mm |
| Thermal Power (Pe) | 20.0 W |
| Nominal Diameter | 3.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Visaton SL 87 WP 4 OHM?
Load Forge's calculated alignment puts Visaton SL 87 WP 4 OHM in a 1.9 liter vented enclosure tuned to 137.7 Hz, reaching an F3 cutoff of approximately 232.1 Hz.
Can Visaton SL 87 WP 4 OHM be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.37 liters with a Qtc of 3.055 (above Butterworth: Qtc cannot fall below Qts (2.16)), the system exhibits an F3 of 321.4 Hz.
What port dimensions should be used for Visaton SL 87 WP 4 OHM to avoid port chuffing?
Xmax is not published for Visaton SL 87 WP 4 OHM, so the port is an empirical estimate: a 5.0 cm diameter with a length of 12.8 cm (area at least 12 in² per ft³ of net volume). Check the air velocity at your power level in Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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