Sealed MTM center — dual SB17 + Dayton ND25FA
2× SB Acoustics SB17NRX2C35-4 + Dayton Audio ND25FA-4 · 18 L sealed box · 2-way Linkwitz-Riley 4th-order at 2.5 kHz
Drivers
- WooferSB Acoustics SB17NRX2C35-4×24 Ω · Fs 36 Hz
- TweeterDayton Audio ND25FA-4×14 Ω · Fs 1350 Hz
Crossover
| Type | Linkwitz-Riley |
| Slope | 24 dB/oct (4th order) |
| Crossover point | 2.5 kHz |
Tune component values in the crossover designer.
Compatibility check
ValidatedThis recipe passes the Sine Design compatibility engine with no errors — the enclosure alignment and crossover are sensible for these drivers. Notes below are informational.
About this design
A horizontal MTM center to timbre-match the SB17 bookshelf for a home-theatre front stage: two SB17 midwoofers flanking the ND25FA dome in an 18 L sealed box. Crossed at 2.5 kHz (LR4). Two 4 Ω woofers in parallel make a nominal 4 Ω load. A true MTM has a vertical lobing trade-off when laid on its side — keep the listening axis on the tweeter and the crossover low.
Want to change a driver, the box size or the crossover point? Open this recipe in the builder — every slot is pre-filled, and the live compatibility check follows your edits. Published Thiele/Small parameters are nominal; measure your drivers (DATS/REW) and model the final cabinet before building.
Estimated parts list
| Part | Qty | Est. | Buy |
|---|---|---|---|
| SB Acoustics SB17NRX2C35-4 | 2 | — | Parts Express → |
| Dayton Audio ND25FA-4 | 1 | — | Parts Express → |
| 0.47 mH air-core inductor (L3 series) | 1 | $6 | Parts Express → |
| 27 µF film capacitor (C3 shunt) | 1 | $3 | Parts Express → |
| 0.22 mH air-core inductor (L4 series) | 1 | $6 | Parts Express → |
| 5.6 µF film capacitor (C4 shunt) | 1 | $3 | Parts Express → |
| 8.2 µF film capacitor (C1 series) | 1 | $3 | Parts Express → |
| 0.15 mH air-core inductor (L1 shunt) | 1 | $6 | Parts Express → |
| 18 µF film capacitor (C2 series) | 1 | $3 | Parts Express → |
| 0.68 mH air-core inductor (L2 shunt) | 1 | $6 | Parts Express → |
| Binding-post terminal cup | 1 | $6 | Parts Express → |
| Acoustic damping / polyfill (~180 g) | 1 | $9 | Parts Express → |
| Cabinet panel stock (MDF/ply) for ~18 L net | 1 | $45 | local |
| Fasteners, gasket & sealant | 1 | $6 | local |
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