JBL 123A
Thiele-Small parameters
| Nominal size | 12" |
|---|---|
| Impedance | 8 Ω |
| Fs | 25 Hz |
| Qts | 0.49 |
| Qes | 0.52 |
| Qms | 8.5 |
| Vas | 235 L |
| Sd | 486.5 cm² |
| Xmax | 7.9 mm |
| Re | 4.4 Ω |
| Bl | 8.7 T·m |
| Mms | 57.2 g |
| Pe | 100 W |
| Sensitivity | 93.1 dB |
Alignment hint
| EBP | 48 · sealed |
|---|---|
| Sealed Vb (Qtc ≈ 0.71) | ≈ 217.1 L |
EBP < 50: favours a sealed (closed) 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 |
|---|---|---|---|---|---|---|---|---|
| JBL 2213H | 25 = | 0.49 = | 235 = | 7.9 = | 93.1 = | close | 75 W vs 100 W: lower power handling | + |
| JBL 2213 | 25 = | 0.49 = | 235 = | 6.8 -1.1 | 93.1 = | close | 50 W vs 100 W: lower power handling · Xmax 6.8 mm < 7.9 mm: lower excursion-limited SPL | + |
| Alpine 6126GX | 26 +1 | 0.532 +0.04 | 233 -2 | 8.2 +0.3 | 94.5 +1.4 | close | 4 Ω vs 8 Ω: amp load changes | + |
| Peerless SLS315 | 24.4 -0.6 | 0.452 -0.04 | 205.2 -29.8 | 7.8 -0.1 | 91.4 -1.7 | close | Xmax 7.8 mm < 7.9 mm: lower excursion-limited SPL | + |
| SB Acoustics SB34NRX75-6 vp | 22.2 -2.8 | 0.444 -0.05 | 240 +5 | 11 +3.1 | 92 -1.1 | close | + | |
| Peerless 315SWR | 24 -1 | 0.433 -0.06 | 210 -25 | 8 +0.1 | 91.3 -1.8 | close | + | |
| Peerless 831857 | 24 -1 | 0.433 -0.06 | 210 -25 | 9 +1.1 | 91.3 -1.8 | close | + | |
| Philips AD12250W8 vp doum2 | 28.7 +3.7 | 0.51 +0.02 | 237 +2 | 6 -1.9 | 92.5 -0.6 | close | Xmax 6 mm < 7.9 mm: lower excursion-limited SPL | + |
| Rockford Fosgate R1S4-12 | 22 -3 | 0.493 = | 197.2 -37.8 | 7 -0.9 | 91.5 -1.6 | usable | 4 Ω vs 8 Ω: amp load changes · Xmax 7 mm < 7.9 mm: lower excursion-limited SPL | + |
| Davis 31ST12M | 24 -1 | 0.399 -0.09 | 260 +25 | 8.9 +1 | 91.6 -1.5 | usable | + |
Compare the closest 3 against the 123A →
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.