Speaker Lab render
Penn Audio Install Line · Low-tuned 18″ subwoofer
Penn IL18
Subwoofer. Vented. Deep.
1 × 18″ · twin front slot vents · 26.8 Hz tuning
| Bandwidth | 24 Hz – 107 Hz |
|---|---|
| Max SPL | 120 dB peak (10 ms) / 109 dB continuous |
| Tuning | 26.8 Hz |
| Impedance | 4 ohms |
| Transducers | 1 × 18″ (1500 W AES) |
Overview
What it is.
One 18-inch driver centered between two front-firing slot vents, tuned to 26.8 Hz from the vent geometry itself. The vent was chosen on Speaker Lab's combined response, on the floor, with the protection filter the cabinet needs — not from a rule of thumb.
Runs on its supplied DSP preset: an 80 Hz Linkwitz-Riley low-pass and a 19.5 Hz protective high-pass that keeps the cone inside its excursion limit below tuning.
Response
Modeled in the Speaker Lab.
On-axis response at 2.83 V / 1 m from the full system model — drivers, cabinet, crossover, vents and DSP preset together.
Specifications
Engineered, then verified.
| Frequency response (−5 dB, modeled, DSP preset) | 24 Hz – 107 Hz |
|---|---|
| Maximum SPL (1 m, modeled, with 530 W amplifier) | 120 dB peak (10 ms) / 109 dB continuous |
| Nominal impedance | 4 ohms |
| Cabinet tuning | 26.8 Hz |
| Processing | DSP preset: LR4 80 Hz low-pass · LR4 19.5 Hz high-pass · limiter |
| Transducer | 1 × 18″ (1500 W AES) |
| Enclosure | Vented, twin front slots, Baltic birch |
| Dimensions (W × H × D) | 40.0 × 20.0 × 30.0 in (1016 × 508 × 762 mm) |
| Weight (modeled) | 69 kg (151 lb) |
| Connections | 2 × NL4 (INPUT, LINK) |
| Finishes | Black or white as standard; any finish in the Penn Audio Custom library to order |
Inside the design
Why it’s built this way.
Tuned from geometry
Two 7 × 40 cm slots, 62 cm deep, along the side walls: 293 L net, 26.8 Hz, both vents front-firing.
Protected by design
Limiter and subsonic set from the modelled excursion limit (about 530 W into 4 Ω), so the preset is the safe one.
Front-firing
Driver and vents on one face: it can sit against a wall or in a stage front without losing its tuning.
Install hardware
Two NL4 connectors (input and link). Baltic-birch cabinet, 40 × 20 × 30 in.
Penn Audio Install Line
Hear it in your room.
Tell us about the space and the program — we’ll spec the system around it.