The24 SUB PRO PASSIVE SEALED infrasub is a statement.

Its huge cone surface area and huge 90 mm of linear stroke - represents a world record for cinema subwoofers - allow it to move a gigantic volume of 10 liters of air per stroke to pressurize the room. Due to its ultra-low resonance frequency and its sealed enclosure design the group delay is several times faster than the smaller 18", 15" or 12" subwoofers at the same frequency. Also the acoustic power output per cubic inch is by far in favour of this unique design compared to stacked multiple smaller subwoofers.

Its ingenious design allows the The24 SUB PRO to produce frequencies in the infrasonic frequency range with authority, reaching down lower than subwoofers with a smaller diaphragm surface ever will. At the same time this infrasub renders those notes with much more power, structure and resolution.

The The24 SUB PRO ideally suits not only all types and sizes of cinemas, but also high-end stereo systems. Much of the spacial room information of the recording envirnment in a great audiophile recording is contained in the sub 30Hz audio band. You will hear more details in mid and high frequencies.

Technical Data

Speaker type

24" forward-firing woofer, with dual 5" voice coil


45 mm excursion each direction (90 mm linear), voice coil remaining in homogeneous magnetic field, linear and lowest distortion

Passive | Active


Recommended amplifiers 

2 Amp. channels are required. minimum recommended amplifier voltage swing:  2 x 109 Vrms, 154 Vpk, 27,3 A; equivalent to 3000W@4Ohms per channel, total 6000W with correct RMS & Peak limiter settings (up to 450V = 20kW peak)

Recommended ASCENDO amplifiers  




SPL (Peak / half space 2 pi) 

Measurement data
140 dB @32Hz and up
120 dB @20 Hz
104 dB @10 Hz

Frequency range

"Measurement Data (without ext. DSP)
28 Hz - 500 Hz /   -3 dB
20 Hz - 500 Hz / -15 dB"


90 dB  / 1W/m

Power handling 

2 x 2500 W


Dual voice coil, 4 Ω each

Air volume displacement 

9,9 L / in comparison 18" standard cinema subwoofer 1,1 L

Directivity horizontal x vertical in Deg°


Input terminal

Neutrik NL4 MP


Internally braced birch ply and MDF


29,53 " | 750 mm


43,31 " | 1100 mm

Hight with feet 

44,29 " | 1125 mm

Depth without grill 

19,69 " | 500 mm

Depth with plug

19,69 " | 500 mm


255,74 lbs | 116 kg


Structural paint black

Custom colour options 

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

Shape customization 

Upon request 


Floor standing with feet


Technical modifications subject to change without further notice