The18 SUB PRO PASSIVE SEALED SH subwoofer is so far above and beyond the competition in every aspect; refined musicality, tightness, and output levels suitable for a 18" driver. Combine this exceptional performance with an enclosure only 10,43” deep to accommodate a wider range of applications where larger enclosures just can’t fit, and this model could possibly take the home theater market by storm.

The 18” driver is an advanced carbon rohacell composite sandwich cone. It is coupled with a neodymium motor with 4” Ultra-high-temperature voice coil. With a max SPL of 137dB @100Hz an , the dynamic expression and percussive impact that this sub can deliver puts it in a class by itself, let alone in such a shallow footprint as to almost disappear in home theaters or media rooms when compared to more traditional cube subwoofer designs.

In larger rooms where more output is needed (or just desired), ASCENDO also offers a Dual-18” version of this same enclosure design, with the two woofers stacked - The18-2 SUB PRO PASSIVE SEALED SH. The 143dB SPL @100Hz capability of this 48” high, 24” wide and only 11” deep defies belief until experienced.

Both models are engineered to operate perfectly in sync (in phase) with our Infrasonic subwoofers; The24, The32, The50 and The80 when there is a desire to reproduce movie content below 20Hz with the same authority, precision, and musicality. The combined results sound (and feel) like seamless and natural extensions of their individual efforts, adding to the overall addictive, immersive quality of a complete ASCENDO system.


Technical Data

Speaker type

18" forward-firing, advanced carbon rohacell composite sandwich cones, neodymium motor with 4” ultra-high-temperature Voice-coil


23mm Xmax excursion each direction (46 mm linear), voice coil remaining in homogeneous magnetic field

Passive | Active


Recommended amplifiers 

1Ch Amplifier are required. Min. recommended amplifier:  89 Vrms, 126 Vpk, 22,5 A; equivalent to 2000W@4 Ohm, with correct RMS & Peak limiter settings. (up to 3kW)

Recommended ASCENDO amplifiers  

(With additional external 1CH DSP: AIA2-6004),  DSP4-10K2



SPL (Peak / half space 2 pi) 


Measurement Data
130 dB @60 Hz and up
117 dB @24 Hz

Frequency Range 

Measurement Data (without ext. DSP)
38 Hz - 500 Hz /   -3 dB
23 Hz - 500 Hz / -15 dB


89 dB  / 1W/m 4 pi, 93 dB / 1W/m 2 pi

Power handling 

2500 W


4 Ω  

Air volume displacement 

2,66 L / in comparison 18" standard cinema subwoofer 1,1 L

Directivity horizontal x vertical in Deg°


Input terminal

4-conductor Phoenix 12 AWG (3,3 mm²) 


Internally braced MDF


21,14 " | 537 mm


26,65 " | 677 mm

Hight with feet 

27,24 " | 692 mm

Depth without grill 

10,43 " | 265 mm

Depth with plug

10,43 " | 265 mm


79,37 lbs | 36 kg


Satin matte black

Custom colour options 

Piano lacquer, colour of choice, matt or other finishes upon request

Shape customization 

Upon request 


Floor standing with feet


The18 SUB PRO PASSIVE SEALED SH is supplied with a front cover as standard

Technical modifications subject to change without further notice