Dolby SB218XL – Dual 18-Inch PLF Cinema Subwoofer
Dolby SB218XL – Dual 18-Inch PLF Cinema Subwoofer is backordered and will ship as soon as it is back in stock.
Dolby SB218XL – Dual 18-Inch PLF Cinema Subwoofer
What is the Dolby SB218XL?
The Dolby SB218XL is a dual 18-inch, front-loaded subwoofer designed for premium large-format (PLF) cinema auditoriums. It produces deep, clean sub-bass for the LFE channel in Dolby Atmos, Dolby Surround 7.1 and 5.1 rooms. Two pro-audio 18-inch drivers with 4-inch voice coils and up to 48 mm of peak-to-peak excursion give it Dolby's highest subwoofer output, rated at 1600 W.
How does the Dolby SB218XL work?
The SB218XL is a passive cabinet driven by external amplifier channels using Dolby's required high-pass and low-pass processing. Each driver has its own acoustic chamber and port, which improves performance and structural integrity. An aluminum demodulation ring and optimized cooling system in each driver reduce distortion at high drive levels.
The advanced input plate carries a high-current, spring-loaded terminal block and a flip-card PCB. Flipping the card selects parallel 4-ohm operation on one amplifier channel or independent 8-ohm drive of each woofer, without opening the cabinet. Rated at 1600 W @ 80 Vrms with an 1140 W measured power draw, the SB218XL reaches 134 dB continuous and 144 dB measured peak SPL at one metre, with response from 22 Hz to 170 Hz and usable output to 19 Hz.
The LFE signal typically comes from a Dolby CP950A Atmos cinema processor, with amplification from a Dolby Multichannel Amplifier such as the DMA32301. Two cabinets can be stacked using the rubber feet and indexing recesses, and the BKT.136 tie plates and BKT.FLR floor brackets (sold separately) lock the stack together and to the floor.
What are the key features of the Dolby SB218XL?
- PLF-grade dual 18-inch drivers — 4-inch voice coils with up to 48 mm of peak-to-peak excursion deliver the impact premium large-format rooms demand.
- Flip-card input plate — one card selects parallel or independent wiring without opening the cabinet.
- Individual chambers and porting — each driver has its own chamber and port for better performance, structural integrity and reliability.
- Low-distortion motor design — an aluminum demodulation ring and optimized cooling keep distortion down at high output.
- Two-high stacking — rubber feet, indexing recesses and threaded inserts support a secure two-unit stack.
- Balance-centered handles — handles placed at the balance point make it easier to unpack and position the 207.5 lb cabinet.
Where is the Dolby SB218XL typically used?
- Premium large-format cinema auditorium
- Screening room
- Auditorium
- House of worship
Technical Specifications
| Model | SB218XL |
| Frequency range | 22 Hz - 170 Hz |
| Usable LF response | 19 Hz |
| Coverage window | Omni |
| Rated impedance | 4 Ohms / 8 Ohms independent drive |
| Sensitivity @ 1 W | 102 dB |
| Power handling | 1600 W @ 80 Vrms |
| Power draw | 1140 W |
| Maximum voltage peak | 200 Vpk |
| Max continuous SPL @ 1 m | 134 dB |
| Measured peak SPL @ 1 m | 144 dB |
| Transducers | LF - 18" woofer (x 2) |
| Enclosure | Wood |
| Accessories | BKT.136 tie plates and BKT.FLR floor brackets (sold separately) |
| Dimensions (unit) | 30" H x 50.5" W x 25.2" D (76.2 x 128.26 x 64 cm) |
| Weight (unit) | 207.5 lb (94.1 kg) |
| Weight (shipping) | 225.5 lb (102.3 kg) |
Frequently Asked Questions
Is the SB218XL compatible with Dolby Atmos and the CP950A?
Yes. Dolby designed the SB218XL for the LFE channel in Dolby Atmos, Dolby Surround 7.1 and 5.1 auditoriums, fed from a Dolby cinema processor such as the CP950A or CP950 through external amplification.
Can one amplifier channel drive the SB218XL?
Yes. In parallel mode the cabinet presents 4 ohms to a single channel. Set the flip card to independent mode to drive each woofer at 8 ohms from separate channels.
How many SB218XL cabinets can be stacked?
Dolby allows two units per stack, coupled with BKT.136 tie plates and anchored with BKT.FLR floor brackets (both sold separately). Read the owner's manual before mounting.
How does the SB218XL differ from the SB218?
The SB218XL is the PLF model, rated at 1600 W with 19 Hz usable response and a flip-card input. The SB218 is rated at 1200 W with 22 Hz usable response for mainstream auditoriums.
What warranty and support are available?
The SB218XL carries Dolby's manufacturer warranty, and Creation Networks confirms the current terms with your quote. Creation Networks designs, installs and supports complete Dolby cinema systems; browse the Dolby Professional collection or request a quote.
At Creation Networks, we do everything we can to create an excellent customer experience. This includes fast shipping and easy returns.
- Most in-stock orders placed Monday-Friday ship within 24-48 hours. General restrictions apply; please see our full shipping policy here.
- We offer a 30-day return policy from the delivery date on many products. Product restrictions apply. Restocking fees for the return of open-box items. Please see our full return policy here for more information.
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