Seas Prestige MR18REX_XF-1699-08_06
Best box: 3.6 L bass reflex tuned to 107.1 Hz · F3 122.8 Hz
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Comparable 6.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Seas Prestige MR18REX_XF-1699-08_06 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 (2.4 L at 107.1 Hz) would need a 17.8 cm port; the recommendation is retuned to 3.6 L at 107.1 Hz so the port can be built.
- Limited linear excursion (Xmax: 3.0 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) | 3.6 Liters |
| Tuning Frequency (Fb) | 107.1 Hz |
| F3 (-3 dB Cutoff) | 122.8 Hz |
| F6 / F10 Extension | 98.8 Hz / 81.7 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 10.7 cm |
| First Pipe Resonance | 1611.0 Hz |
| Estimated MOL @ F3 | 113.4 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.69 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 0.976; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 3.0 Liters |
| System Q (Qtc) | 0.976 (above Butterworth) |
| System Resonance (Fc) | 178.2 Hz |
| F3 (-3 dB Cutoff) | 153.4 Hz |
| F6 / F10 Extension | 123.6 Hz / 97.3 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 126.0 Hz |
| Total Q (Qts) | 0.69 |
| Electrical Q (Qes) | 0.954 |
| Mechanical Q (Qms) | 2.49 |
| Equivalent Volume (Vas) | 3.0 Liters |
| Diaphragm Area (Sd) | 126.0 cm² |
| DC Resistance (Re) | 6.2 Ω |
| Efficiency Bandwidth Product (EBP) | 132.0 |
| Linear Excursion (Xmax) | 3.0 mm |
| Thermal Power (Pe) | 250.0 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 Seas Prestige MR18REX_XF-1699-08_06?
Load Forge's calculated alignment puts Seas Prestige MR18REX_XF-1699-08_06 in a 3.6 liter vented enclosure tuned to 107.1 Hz, reaching an F3 cutoff of approximately 122.8 Hz.
Can Seas Prestige MR18REX_XF-1699-08_06 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 3.0 liters with a Qtc of 0.976 (above Butterworth), the system exhibits an F3 of 153.4 Hz.
What port dimensions should be used for Seas Prestige MR18REX_XF-1699-08_06 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 10.7 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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