JBL GT 122

12" · 4 Ω · 140 W · 96.3 dB

Thiele-Small parameters

Nominal size	12"
Impedance	4 Ω
Fs	33 Hz
Qts	0.35
Qes	0.364
Qms	9.3
Vas	101 L
Sd	532 cm²
Xmax	5.1 mm
Re	2.95 Ω
Bl	12.4 T·m
Mms	91.4 g
Pe	140 W
Sensitivity	96.3 dB

Alignment hint

EBP	91 · flexible
Sealed Vb (Qtc ≈ 0.71)	≈ 32.8 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
Davis 39RCA15 v2024	32.8 -0.2	0.346 =	99.5 -1.5	5.8 +0.7	93.4 -2.9	close	8 Ω vs 4 Ω: amp load changes	+
Audio Dynamique 320/75	32 -1	0.341 -0.01	116 +15	5 -0.1	93.8 -2.5	close	8 Ω vs 4 Ω: amp load changes · Xmax 5 mm < 5.1 mm: lower excursion-limited SPL	+
Fane SOVEREIGN PRO 12-300S	40 +7	0.321 -0.03	101.3 +0.3	5.3 +0.2	96.5 +0.2	close	8 Ω vs 4 Ω: amp load changes	+
Beyma 12BR70 vp jp	33.7 +0.7	0.365 +0.02	104 +3	4.4 -0.7	93.1 -3.2	close	8 Ω vs 4 Ω: amp load changes · Xmax 4.4 mm < 5.1 mm: lower excursion-limited SPL	+
Kartesian WOM300_vDIY	37 +4	0.362 +0.01	91.7 -9.3	6.4 +1.3	94.6 -1.7	close	8 Ω vs 4 Ω: amp load changes	+
Beyma 12BR70 v2	35 +2	0.355 +0.01	100 -1	4.1 -1	93.4 -2.9	close	8 Ω vs 4 Ω: amp load changes · Xmax 4.1 mm < 5.1 mm: lower excursion-limited SPL	+
Eminence KAPPALITE 3012 LF	37 +4	0.324 -0.03	106.7 +5.7	8.2 +3.1	95.5 -0.8	close	8 Ω vs 4 Ω: amp load changes	+
MAG Audio SUB 300	30.3 -2.7	0.323 -0.03	110.7 +9.7	7.4 +2.3	95.1 -1.2	close		+
PHL Audio 4530P	42 +9	0.36 +0.01	93 -8	6 +0.9	96.1 -0.2	close	8 Ω vs 4 Ω: amp load changes	+
PHL Audio 4531	42 +9	0.36 +0.01	93 -8	6 +0.9	96.1 -0.2	close	8 Ω vs 4 Ω: amp load changes	+

Compare the closest 3 against the GT 122 →

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.