PURIFI PTT5.25M04-NFA-02
Best box: 1.6 L bass reflex tuned to 89.9 Hz · F3 98.1 Hz
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Comparable 5.25" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the PURIFI PTT5.25M04-NFA-02 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 (1.6 L at 74.9 Hz) would need a 62.0 cm port; the recommendation is retuned to 1.6 L at 89.9 Hz so the port can be built.
- Limited linear excursion (Xmax: 2.9 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) | 1.6 Liters |
| Tuning Frequency (Fb) | 89.9 Hz |
| F3 (-3 dB Cutoff) | 98.1 Hz |
| F6 / F10 Extension | 85.9 Hz / 74.2 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 41.9 cm |
| First Pipe Resonance | 410.0 Hz |
| Estimated MOL @ F3 | 112.9 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 0.98 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 146.6 Hz |
| F3 (-3 dB Cutoff) | 130.9 Hz |
| F6 / F10 Extension | 101.5 Hz / 77.0 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 40.0 Hz |
| Total Q (Qts) | 0.19 |
| Electrical Q (Qes) | 0.195 |
| Mechanical Q (Qms) | 6.9 |
| Equivalent Volume (Vas) | 12.6 Liters |
| Diaphragm Area (Sd) | 85.0 cm² |
| DC Resistance (Re) | 3.8 Ω |
| Efficiency Bandwidth Product (EBP) | 204.7 |
| Linear Excursion (Xmax) | 2.9 mm |
| Thermal Power (Pe) | N/A W |
| Nominal Diameter | 5.25" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for PURIFI PTT5.25M04-NFA-02?
Load Forge's calculated alignment puts PURIFI PTT5.25M04-NFA-02 in a 1.6 liter vented enclosure tuned to 89.9 Hz, reaching an F3 cutoff of approximately 98.1 Hz.
Can PURIFI PTT5.25M04-NFA-02 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.98 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 130.9 Hz.
What port dimensions should be used for PURIFI PTT5.25M04-NFA-02 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 41.9 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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