Monacor SPA-46

18" · 4 Ω · 300 W · 99.8 dB

Thiele-Small parameters

Nominal size	18"
Impedance	4 Ω
Fs	30 Hz
Qts	0.25
Qes	0.26
Qms	6.65
Vas	285 L
Sd	1180 cm²
Xmax	4 mm
Re	3.94 Ω
Bl	23.5 T·m
Mms	192.8 g
Pe	300 W
Sensitivity	99.8 dB

Alignment hint

EBP	115 · ported
Sealed Vb (Qtc ≈ 0.71)	≈ 40.7 L

EBP > 100: favours a ported (bass-reflex) 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
Monacor SP-46A/500PA	30 =	0.25 =	285 =	6 +2	97.7 -2.1	close	8 Ω vs 4 Ω: amp load changes	+
B&C 18 PZB 100	30 =	0.243 -0.01	297 +12	7.8 +3.8	98.8 -1	close	8 Ω vs 4 Ω: amp load changes	+
P.Audio SD-18	33.2 +3.2	0.26 +0.01	264.3 -20.7	5 +1	99.5 -0.3	close	8 Ω vs 4 Ω: amp load changes	+
Oberton 18NSW700-8	30.5 +0.5	0.243 -0.01	309 +24	7.7 +3.7	98.6 -1.2	close	8 Ω vs 4 Ω: amp load changes	+
Monacor SP-46/500PA	30 =	0.271 +0.02	333 +48	5 +1	98.5 -1.3	close	8 Ω vs 4 Ω: amp load changes	+
B&C 18PZB100	30 =	0.24 -0.01	297 +12	8 +4	97 -2.8	close	8 Ω vs 4 Ω: amp load changes	+
PD PD 184	33.4 +3.4	0.266 +0.02	304 +19	7.2 +3.2	99.9 +0.1	close	8 Ω vs 4 Ω: amp load changes	+
Precision Devices PD 184	33.4 +3.4	0.266 +0.02	304 +19	7.2 +3.2	99.9 +0.1	close	8 Ω vs 4 Ω: amp load changes	+
Radian 2218Neo	30 =	0.23 -0.02	312 +27	9 +5	99 -0.8	close	8 Ω vs 4 Ω: amp load changes	+
B&C 18 NW 100	31 +1	0.254 =	252 -33	8.7 +4.7	98.4 -1.4	close	8 Ω vs 4 Ω: amp load changes	+

Compare the closest 3 against the SPA-46 →

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.