JBL GT 120
Thiele-Small parameters
| Nominal size | 12" |
|---|---|
| Impedance | 4 Ω |
| Fs | 24.8 Hz |
| Qts | 0.429 |
| Qes | 0.46 |
| Qms | 6.46 |
| Vas | 91.1 L |
| Sd | 531 cm² |
| Xmax | 8.1 mm |
| Re | 3.56 Ω |
| Bl | 14.7 T·m |
| Mms | 179.4 g |
| Pe | 250 W |
| Sensitivity | 90.3 dB |
Alignment hint
| EBP | 54 · flexible |
|---|---|
| Sealed Vb (Qtc ≈ 0.71) | ≈ 53.1 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 |
|---|---|---|---|---|---|---|---|---|
| JBL GT 120MKII | 24.8 = | 0.429 = | 91.1 = | 8.1 = | 90.3 = | close | + | |
| JBL GT4-12 | 24.8 = | 0.429 = | 91.1 = | 8.1 = | 90.3 = | close | + | |
| JBL CS1204 | 24.8 = | 0.429 = | 91.1 = | 6.3 -1.8 | 90.3 = | close | Xmax 6.3 mm < 8.1 mm: lower excursion-limited SPL | + |
| Focal SUB12 | 24 -0.8 | 0.407 -0.02 | 90 -1.1 | 9.8 +1.7 | 90.7 +0.4 | close | + | |
| Dayton Audio DCS305-4 v2015 | 24.2 -0.6 | 0.396 -0.03 | 92.3 +1.2 | 8.4 +0.3 | 90.7 +0.4 | close | + | |
| Dayton Audio DCS305-4 v2017 | 24.2 -0.6 | 0.396 -0.03 | 92.3 +1.2 | 8.4 +0.3 | 90.7 +0.4 | close | + | |
| Dayton Audio DCS305-4 v2018 | 24.2 -0.6 | 0.396 -0.03 | 92.3 +1.2 | 8.4 +0.3 | 90.7 +0.4 | close | + | |
| Dayton Audio DCS305-4 v2021 | 24.2 -0.6 | 0.396 -0.03 | 92.3 +1.2 | 8.4 +0.3 | 90.7 +0.4 | close | + | |
| TC Sounds EPIC 12 DVC v2009 | 24 -0.8 | 0.399 -0.03 | 91.2 +0.1 | 11.7 +3.6 | 90.1 -0.2 | close | + | |
| Rythmik Audio DS1200 | 26 +1.2 | 0.444 +0.02 | 88 -3.1 | 8.8 +0.7 | 91.7 +1.4 | close | + |
Compare the closest 3 against the GT 120 →
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.