RARE FIND. Excellent condition and One of the best 18" speakers ever made! For those who know what this is, then you’re in for a treat. Loud, punchy, thunderous… These were used in high end OAP subwoofers. Bow down to this wonderful beast of a speaker in excellent condition. I acquired this when I bought all the remaining gear from a defunct production company in Atlanta. It is missing one small segment of the gasket which is easily replaced. They did tours for Keith Urban, James Brown and TLC that I found road cases for, so they were using high quality production components. This speaker is HEAVY DUTY.

Electro mechanical specifications Nominal chassis diameter (inches-mm) 18 inch/457 mm Impedance (ohms) 4,8 or 16 Power Handling (A.E.S)1 400 (A.E.S.)1 

Maximum output (dB) continuous/peak 122/128 dB 

Power compression at rated power (dB) 3.0 dB 

Usable Frequency range (-6dB) Hz-kHz 35 Hz-1.5 kHz 

Average Sensitivity (in above range) 1W/1m 98.5 

Resonance (Hz) 30 Hz 

Moving mass inc. air load (grams) 148 grams 

BL product (Newtons/amp) 29.4 

Minimum impedace (Zmin) (ohms) 7.8 

Effective piston diameter (mm) 14.84 inch/377 mm 

Flux Density (Tesla) 1.0 

Tesla Magnetic gap depth 0.39 inch/10 mm Coil winding height 0.67 inch/17 mm 

Voice coil length 100 feet/30 

M Magnet weight 120 oz/3.4 Kg 

Maximum cone displacement 0.70 inch/18 mm 

Peak displacement volume of cone, Vd 0.896 

Litres Voice coil diameter 4.0 inch/101.6 mm 

Construction materials Coil former Fibreglass 

Voice coil material Copper 

Magnet Ferrite 

Chassis Die Cast Aluminium 

Cone Paper Surround/edge termination Polyvinyl Damped 

Fabric Dust dome Paper Connectors 

Push Button Spring Terminals 

Polarity Positive voltage at red terminal causes forward motion of cone 

Thiele-Small parameters 

Resonant frequency fs (Hz) 30.5 Hz 

D.C resistance Re (ohms) 6.35 

Qts 0.197 

Qes 0.207 

Qms 4.03 Mms (grams) 148 

Cms (microns per Newton) 184 

BL product (Tesla metres) 29.5 

Tesla metres Vas (litres) 320 litres 

Reference efficiency no (%) 4.25% 

Piston area Sd (m2) 0.112 m2 

Xmax (mm) 4.0 mm 1

 

A.E.S. power handling test. 

Pink noise bandpass filtered at 12 dB per octave with cutoff frequencies of 35 Hz and 350 Hz. 

Driver mounted in free air, test signal applied at rated power for two hours