What Is the L-Acoustics KS28?

The L-Acoustics KS28 is a dual-18-inch high-power subwoofer designed for large-scale touring and fixed installations. It is part of the L-Acoustics K Series ecosystem and is most often paired with K1 and K2 line arrays to deliver low-frequency extension for arenas, stadiums, festivals, and large houses of worship.

The KS28 is known for its high SPL output, cardioid-capable deployment, and compatibility with LA-RAK and LA amplified controllers. For rental companies and venue operators, it is a workhorse sub that holds its value well on the secondary market.

Key Specifications at a Glance

  • Transducers: 2 x 18-inch neodymium drivers
  • Frequency range: approximately 25 Hz to 100 Hz (system-dependent)
  • Nominal impedance: 2 x 8 ohms (dual-channel drive)
  • Rigging: Integrated rigging compatible with K Series flying hardware
  • Amplification: Requires LA amplified controllers (LA12X, LA4X, or similar)
  • Presets: Dedicated KS28 presets via LA Network Manager

Note: Always confirm exact specs against the official L-Acoustics datasheet for the specific production revision.

Typical Applications

  • Touring sound reinforcement — stadium and arena tours needing high-output sub bass
  • Festival main stages — where sub arrays are flown or ground-stacked in large blocks
  • Fixed installations — concert halls, clubs, and large worship venues
  • Cardioid sub arrays — for controlling low-frequency energy on stage

Because the KS28 is a system component, it is normally deployed in multiples — often 12, 16, or more cabinets per side depending on the venue.

Buying Used KS28: What to Check

When sourcing second-hand KS28 units, focus on these points:

1. Driver condition — cone integrity, surround condition, and any recone history.
2. Cabinet and rigging — check for impact damage, bent rigging plates, and worn pins.
3. Grille and connectors — SpeakON/terminal condition and grille dents.
4. Amplifier matching — confirm your LA amplified controllers have the correct presets and firmware.
5. Service history — units from reputable rental inventories are usually better documented.

At Acoustrade we supply tested used line array subwoofers, including KS28-compatible systems, alongside used amplifiers, used line array speakers, and used mixers and microphones for complete venue builds.

Matching KS28 With a Full System

A KS28 array rarely travels alone. A typical package includes:

  • Main hangs: L-Acoustics K1 or K2 line arrays
  • Subs: KS28 in ground-stacked or flown configuration
  • Amplification: LA12X or LA4X racks
  • Processing: LA Network Manager for tuning
  • Control: Digital consoles and stage boxes

If you are building a system from scratch, Acoustrade can help you source matching used line array elements, used power amplifiers, and used digital mixers so everything integrates cleanly.

FAQ

Is the KS28 still current?
Yes. The KS28 remains a widely deployed subwoofer in the L-Acoustics catalog and is common in rental inventories worldwide.

Can I use the KS28 without L-Acoustics amplifiers?
Not recommended. The KS28 relies on L-Acoustics presets and amplified controllers for correct response and protection.

How many KS28 cabinets do I need?
It depends on venue size and target SPL. Large arena systems often use 12–24 cabinets per side; smaller rooms use fewer.

Does Acoustrade test used KS28 units before shipping?
Yes. We test used pro audio equipment before it leaves our facility and document condition for buyers.

Can the KS28 be flown?
Yes. With the correct K Series rigging hardware, KS28 cabinets can be flown or ground-stacked.