SUB 218

High-power sub-bass enclosure



Highly efficient, powerful low-frequency loudspeaker fitted with two 18″ transducers with exceptional size-to-power ratio (148.5 dB SPL short-term peak @ 1 m)
Outline ‘E.R.P.’ (‘Energy Retentive Porting’) design assists airflow and enhances transducer efficiency providing tremendous ‘punch’
Finished with Polyurea, featuring amazing durability and superior physical properties
Design file for Outline ‘Openarray’ 3D acoustic simulation software
High-quality permanent installations in any location which requires extended low-frequency reinforcement including dance clubs, live music venues, indoor sports arenas, theme parks and modern worship locations
An ideal partner for all Outline line/point source systems


The SUB 218 enclosure is a high output sub-bass system equipped with two long-excursion 18” transducers. Consequently it is ideal for those applications requiring super-powerful sub bass delivery, including live music and dance venues. SUB 218 is particularly well-suited to reproducing modern dance music as the design provides not only extended low-frequency reproduction (down to 28 Hz) but also tremendous ‘punch’ in and around the frequencies normally produced by both real and synthetic bass drums.
This focus and clarity not only enhances the reproduction of program material but also makes the most efficient use of amplifier power. This is a result of Outline’s proprietary ‘E.R.P.’ (‘Energy Retentive Porting’) design. Based on the principles of fluid dynamics and successfully applied to the science of controlling pneumatic forces within a loudspeaker enclosure, this unique arrangement of specially-shaped ports ensures an optimum airflow. This reduces internal turbulence, maximising the efficiency of the transducers and thus allowing more amplifier power to be converted into acoustic energy. Such a design requires high-precision manufacturing techniques, and Outline’s engineering team have applied some original production techniques to turn an exciting concept into a physical reality.


Frequency Response -10 dB 28 Hz – 250 Hz
Suggested Cross-Over max 120 Hz
Nominal Dispersion Quasi-Omnidirectional
Impedance (Nom/Min) 2 x 8 Ω / 2 x 5.5 Ω
Watt AES (Continuous/Peak) 2 x 1200 W / 2 x 4800 W
Maximum SPL Output * 148.5 dB SPL

                                                                                    * calculated using +10 dB Crest Factor signal @ 1 m, Half space


Component 2 x 18” direct radiation woofers
Connectors 2 x NL4 Pins 1+/1-, 2+/2-
Cabinet Material Baltic birch plywood
Cabinet Finish Black polyurea coating
Grille Epoxy powder coated
Installation Points 16 x M8 threaded points
Height 570 mm – 22 1/2”
Width 1070 mm – 42 1/8”
Depth 750 mm – 29 1/2”
Weight 80 kg – 176.4 lb


SUB 218 Brochure

Jan 2018

SUB Series Brochure

Nov 2019

SUB 218 Architectural Specifications

Dec 2019

SUB 218 User Manual

Oct 2020

SUB Series 2D Drawings

SUB Series 3D Drawings

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