Unknown XT25SC90-04
Best box: 0.007 L sealed · Fc 1173.8 Hz · F3 986.2 Hz
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Comparable 1.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Unknown XT25SC90-04 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
- Straight vent would be -1.7 cm long: not physically buildable as a simple tube. Use a passive radiator, a folded slot port or model a 3D folded duct in Load Forge Studio.
- Limited linear excursion (Xmax: 0.867 mm); set a high-pass subsonic filter at 25–30 Hz when driven with high power.
Textbook Bass Reflex — not recommended
PORT NOT BUILDABLE| Net Box Volume (Vb) | 1.5 Liters |
| Tuning Frequency (Fb) | 705.5 Hz |
| F3 (-3 dB Cutoff) | 671.2 Hz |
| F6 / F10 Extension | 648.0 Hz / 617.1 Hz |
| Port Inner Diameter | Ø 20.0 cm |
| Port Physical Length | No real tube length at this tuning — use a passive radiator |
| First Pipe Resonance | 0.0 Hz |
| Estimated MOL @ F3 | 91.4 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 1.0 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.414; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 0.007 Liters |
| System Q (Qtc) | 1.414 (above Butterworth: Qtc cannot fall below Qts (1.00)) |
| System Resonance (Fc) | 1173.8 Hz |
| F3 (-3 dB Cutoff) | 986.2 Hz |
| F6 / F10 Extension | 848.4 Hz / 703.6 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 830.0 Hz |
| Total Q (Qts) | 1.0 |
| Electrical Q (Qes) | 1.157 |
| Mechanical Q (Qms) | 7.36 |
| Equivalent Volume (Vas) | 0.0 Liters |
| Diaphragm Area (Sd) | 7.1 cm² |
| DC Resistance (Re) | 3.2 Ω |
| Efficiency Bandwidth Product (EBP) | 717.2 |
| Linear Excursion (Xmax) | 0.9 mm |
| Thermal Power (Pe) | 15.0 W |
| Nominal Diameter | 1.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Unknown XT25SC90-04?
A simple ported box is not recommended for Unknown XT25SC90-04: the textbook alignment (1.5 liters tuned to 705.5 Hz) needs a -1.7 cm port, and no nearby retune stays buildable without a bass hump. A sealed box, a passive radiator or a folded duct is the practical choice.
Can Unknown XT25SC90-04 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.007 liters with a Qtc of 1.414 (above Butterworth: Qtc cannot fall below Qts (1.00)), the system exhibits an F3 of 986.2 Hz.
What port dimensions should be used for Unknown XT25SC90-04 to avoid port chuffing?
A straight 20.0 cm port would need -1.7 cm of length, which does not fit a practical cabinet. Use a passive radiator or a folded/3D duct instead of a straight tube.
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