Guitar Bass Pro Audio Custom / OEM
 
SIGMA PRO 18A-2    
SPECIFICATION  
Nominal Basket Diameter 18", 457.2mm
Nominal Impedance* 8 ohms
Power Rating  
Watts 650W
Music Program 1300W
Resonance 28Hz
Usable Frequency Range 41Hz-2.4kHz
Sensitivity*** 99
Magnet Weight 120 oz.
Gap Height 0.375", 9.53mm
Voice Coil Diameter 3", 76.2mm
   
THIELE & SMALL PARAMETERS  
Resonant Frequency (fs) 28Hz

Download PDF Spec Sheet

 

 

Download PDF Cabinet Design

 
DC Resistance (Re) 6.29
Coil Inductance (Le) 1.90mH
Mechanical Q (Qms) 8.28
Electromagnetic Q (Qes) 0.30
Total Q (Qts) 0.29
Compliance Equivalent Volume (Vas) 441.2 liters / 15.6 cu.ft.
Peak Diaphragm Displacement Volume (Vd) 695cc
Mechanical Compliance of Suspension (Cms) 0.24mm/N
BL Product (BL) 22.1 T-M
Diaphram Mass inc. Airload (Mms) 130 grams
Efficiency Bandwidth Product (EBP) 93
Maximum Linear Excursion (Xmax) 6.1mm
Surface Area of Cone (Sd) 1140.0 cm2  
Maximum Mechanical Limit (Xlim) 18.0mm  
     
MOUNTING INFORMATION    
Recommended Enclosure    
Sealed N/A  
Vented 93-212 liters/3.3-7.5 cu.ft.  
Overall Diameter 18", 457.2mm  
Baffle Hole Diameter 16.56", 420.5mm  
Front Sealing Gasket Fitted as standard  
Rear Sealing Gasket Fitted as standard  
Mounting Holes Diameter 0.28", 7.1mm  
Mounting Holes B.C. D. 17.25", 438.2mm  
Depth 8.15", 207mm  
Net Weight 24.5 lbs., 11.1 kg  
Shipping Weight 28.1 lbs., 12.8 kg  
     
MATERIALS OF CONSTRUCTION    
Coil Construction Copper voice coil  
Coil Former Polyimide former  
Magnet Composition Ferrite magnet  
Core Details Vented and extended core  
Basket Materials Die-cast aluminum basket  
Cone Composition Paper Cone  
Cone Edge Composition Cloth cone edge  
Dustcap Composition Solid composition paper dust cap  
     
FOOTNOTES    

*

Please consult www.eminence.com for specifications of models with alternative impedances.
** Multiple units exceed published rating evaluated under EIA 426A noise source and test standard while in a free-air, non-temperature controlled environment.
***

The average on axis output across the usable frequency range when applying 1W/1m into the nominal impedance, i.e. 2.83V/8Ω, 4V/16Ω.  Eminence response curves are measured under the following conditions:  All speakers are tested at 1W/1m using a variety of test set-ups for the appropriate impedance | LMS using 0.25" supplied microphone (software calibrated) mounted 1m from wall/baffle | 2ft x 2ft baffle is built into the wall with speaker mounted flush against a steel ring for minimum diffraction | Carver PM-120 amplifier | 2700ft3 chamber with fiberglass on all six surfaces (three with custom-made wedges).

**** BETA 8CX, 10CX, 12CX and Acoustinator™ CX2008 are coaxial speakers with tweeter sold separately. Published Usable frequency response obtained with APT50 high frequency driver attached.