Fostex FW 250
Thiele-Small parameters
| Nominal size | 10" |
|---|---|
| Impedance | 8 Ω |
| Fs | 23 Hz |
| Qts | 0.225 |
| Qes | 0.23 |
| Qms | 9.5 |
| Vas | 150 L |
| Sd | 350 cm² |
| Xmax | 4.5 mm |
| Re | 6.6 Ω |
| Bl | 15.1 T·m |
| Mms | 54.8 g |
| Pe | 50 W |
| Sensitivity | 91.8 dB |
Alignment hint
| EBP | 100 · flexible |
|---|---|
| Sealed Vb (Qtc ≈ 0.71) | ≈ 16.9 L |
EBP 50-100: works in either a sealed or ported alignment.
Rules of thumb from T/S parameters only. Verify against a real simulation before cutting wood.
Substitute candidates
| Driver | Fs (Hz) | Qts | Vas (L) | Xmax (mm) | Sens (dB) | Fit | Notes | Compare |
|---|---|---|---|---|---|---|---|---|
| ATC SB75-234 LC | 26 +3 | 0.224 = | 120 -30 | 5 +0.5 | 91.8 = | close | + | |
| Eton 11-612C8/50RP | 23 = | 0.289 +0.06 | 152 +2 | 5 +0.5 | 91.7 -0.1 | close | + | |
| Eton 11-581/50 HEX v2015 | 23 = | 0.299 +0.07 | 151 +1 | 5 +0.5 | 91.6 -0.2 | close | + | |
| Monacor SPH-255 | 23 = | 0.238 +0.01 | 205 +55 | 4.5 = | 93 +1.2 | close | + | |
| Audiotechnology FLEXUNITS 10 A 77 25 10 | 25 +2 | 0.26 +0.04 | 140 -10 | 4.3 -0.2 | 90.6 -1.2 | close | Xmax 4.3 mm < 4.5 mm: lower excursion-limited SPL | + |
| SEAS 25F-EWX | 26 +3 | 0.23 +0.01 | 175 +25 | 8 +3.5 | 92.9 +1.1 | close | + | |
| Monacor SPP-280 | 25 +2 | 0.292 +0.07 | 145 -5 | 4.6 +0.1 | 91.7 -0.1 | usable | + | |
| Infinity BETA TWELVE 12 | 22 -1 | 0.242 +0.02 | 158 +8 | 10 +5.5 | 94.8 +3 | usable | 4 Ω vs 8 Ω: amp load changes | + |
| Audiotechnology FLEXUNIT 10A772510 | 25 +2 | 0.258 +0.03 | 140 -10 | 8.6 +4.1 | 92.5 +0.7 | usable | + | |
| Focal 10N 501 | 21.8 -1.2 | 0.231 +0.01 | 212.7 +62.7 | 6 +1.5 | 92.5 +0.7 | usable | + |
Compare the closest 3 against the FW 250 →
Ranked on parameter similarity only (Qts, Fs, Vas, Xmax, sensitivity). Same nominal size required. A hint, not a simulation, model the swap before cutting or buying.
Used in enclosures (0)
No enclosure in the catalog uses this driver yet.