L-Acoustics A15 + KS21 Set

L-Acoustics A15 KS21 Set: Professional Sound System

The L-Acoustics A15 KS21 Set is a professional sound reinforcement package combining 2 L-Acoustics A15 loudspeakers with 2 L-Acoustics KS21 high-power 21-inch subwoofers. Offered at €9,000 per set, this configuration provides a complete A15 and KS21 loudspeaker combination for professional events, touring productions, rental companies and sound reinforcement applications.

The A15 and KS21 were designed to work together as part of the L-Acoustics A Series ecosystem. L-Acoustics describes the KS21 as a compact reference subwoofer designed to extend the bandwidth of A15 and A10 systems, with the KS21 extending the A15 system down to 29 Hz. L-Acoustics documentation also identifies configurations where A15 and KS21 can be flown or stacked together. (L-Acoustics)

Each set includes:

* 2 × L-Acoustics A15
* 2 × L-Acoustics KS21
* €9,000 per set

The combination provides a professional full-range loudspeaker system with dedicated low-frequency reinforcement. The A15 handles the main sound reinforcement duties while the KS21 subwoofers provide extended low-frequency performance.

What Is Included?

Each L-Acoustics A15 KS21 Set contains four loudspeaker enclosures in total:

2 × L-Acoustics A15

The A15 is a 2-way passive 15-inch constant-curvature line source from the L-Acoustics A Series.

L-Acoustics offers the A15 in both A15 Focus and A15 Wide versions. Because this particular listing does not specify which version is included, buyers should confirm whether the available units are A15 Focus or A15 Wide before purchase. (L-Acoustics)

2 × L-Acoustics KS21

The KS21 is a high-power compact 21-inch subwoofer designed to provide low-frequency reinforcement for professional L-Acoustics systems.

L-Acoustics specifies a 29 Hz low-frequency limit and up to 138 dB maximum SPL for the KS21. It uses one 21-inch neodymium cone driver in a bass-reflex enclosure with L-Vents. (L-Acoustics)

Together, these four enclosures form the complete A15 and KS21 set being offered.

L-Acoustics A15

The A15 is part of the L-Acoustics A Series, a family of medium-throw professional loudspeakers designed to provide flexibility and high output.

L-Acoustics describes A15 as a 2-way passive 15-inch constant-curvature line source incorporating L-Vents, DOSC waveguide technology and Panflex adjustable directivity. (L-Acoustics)

The A15 uses a 15-inch low-frequency transducer and a 3-inch diaphragm compression driver. It is a passive loudspeaker with a nominal impedance of 8 ohms and can be amplified using L-Acoustics LA4X, LA8 or LA12X amplified controllers. (L-Acoustics)

The A15 is designed to scale from high-output point-source applications to versatile line-source configurations.

A15 Focus and A15 Wide

L-Acoustics currently offers two versions of the A15: A15 Focus and A15 Wide. (L-Acoustics)

The distinction is important because the two versions have different vertical directivity and slightly different published performance specifications.

A15 Focus

The A15 Focus has a 10-degree vertical directivity and a usable bandwidth of 41 Hz to 20 kHz. L-Acoustics specifies a maximum SPL of 144 dB. It weighs 35 kg / 77 lb. (L-Acoustics)

A15 Wide

The A15 Wide has a 30-degree vertical directivity and a usable bandwidth of 42 Hz to 20 kHz. L-Acoustics specifies a maximum SPL of 141 dB. It weighs 33 kg / 73 lb. (L-Acoustics)

Because your package description only states 2 × A15, this product page should not assign Focus or Wide specifications until the exact inventory has been confirmed.

This approach keeps the listing accurate and avoids presenting the wrong technical specification to potential buyers.

A15 Panflex Directivity

One of the important features of the A15 is Panflex.

L-Acoustics states that Panflex allows the directivity pattern of the line source to be adjusted using the enclosure’s L-Fins. The A15 provides horizontal directivity options of 70°, 90° and 110°, while the A15 Focus and A15 Wide versions differ in their vertical directivity. (L-Acoustics)

This adjustability allows system designers to adapt coverage to different audience geometries.

For professional sound reinforcement, the ability to adjust horizontal coverage can be particularly useful when the system is deployed in different venues or configurations.

A15 L-Vents

The A15 incorporates L-Acoustics L-Vents technology.

L-Acoustics describes L-Vents as a laminar venting technology designed to reduce turbulence and port noise while increasing output capability. The technology is used throughout current L-Acoustics loudspeaker enclosures with low-frequency capacities. (L-Acoustics)

This design contributes to the A15’s low-frequency performance and helps the loudspeaker operate effectively as part of a full-range system.

When combined with the KS21 subwoofer, the system gains dedicated low-frequency reinforcement below the main A15 enclosure’s operating range.

L-Acoustics KS21

The KS21 is the dedicated low-frequency component of this package.

It is a 21-inch high-power compact subwoofer designed for professional sound reinforcement. L-Acoustics specifies one 21-inch neodymium cone driver, a bass-reflex acoustic load with L-Vents and an 8-ohm nominal impedance. (L-Acoustics)

The KS21 provides a low-frequency limit of 29 Hz and a maximum SPL specification of 138 dB under the manufacturer’s stated measurement conditions. (L-Acoustics)

This makes the KS21 an appropriate low-frequency complement to the A15 system.

21-Inch KS21 Subwoofer

The 21-inch driver is one of the defining features of the KS21.

The larger transducer provides the displacement required for high-output low-frequency reproduction in professional sound reinforcement applications.

The KS21 is designed for applications including live concerts, touring, event production and professional rental.

Its 29 Hz low-frequency limit provides extended bass response for music and other program material requiring substantial low-frequency energy.

A15 and KS21 System Integration

The A15 and KS21 are not simply unrelated loudspeaker products being grouped together.

L-Acoustics specifically describes the KS21 as a subwoofer designed to extend the bandwidth of the A15 and A10 systems. The manufacturer’s system specification states that the KS21 couples with A15 to reinforce the system and extend its bandwidth down to 29 Hz. (L-Acoustics)

This makes the A15 KS21 combination a logical system configuration for customers looking for a professional full-range L-Acoustics system.

The A15 provides the main sound reinforcement while the KS21 handles the extended low-frequency portion of the system.

Full-Range Sound Reinforcement

The combination of two A15 loudspeakers and two KS21 subwoofers provides a compact professional system capable of covering both the main audible range and extended low frequencies.

The A15 handles midrange and high-frequency reproduction while also providing low-frequency output from its 15-inch transducer.

The KS21 extends the system’s low-frequency performance to 29 Hz according to L-Acoustics specifications. (L-Acoustics)

This makes the system suitable for productions where both vocal clarity and substantial low-frequency energy are required.

Two A15 Loudspeakers

The inclusion of two A15 loudspeakers allows the package to be configured as a left and right main system.

A two-enclosure configuration can be used for stereo sound reinforcement in appropriate applications.

The actual deployment will depend on the venue, audience geometry, desired coverage and whether the A15 units are being used in point-source, stacked or other supported configurations.

L-Acoustics provides dedicated rigging accessories and system documentation for A15 deployments. (L-Acoustics)

Two KS21 Subwoofers

The package also includes two KS21 subwoofers.

Two subwoofers can provide additional low-frequency output compared with a single enclosure and allow different deployment configurations depending on the production requirements.

The KS21 supports standard and cardioid configurations. L-Acoustics specifies the nominal directivity as standard or cardioid configuration. (L-Acoustics)

The appropriate configuration should be selected using the manufacturer’s current presets and system documentation.

Cardioid KS21 Configuration

The KS21 supports cardioid deployment.

Cardioid subwoofer configurations can be useful when the system designer needs greater control over rearward low-frequency radiation.

This can be particularly valuable on stages where reducing bass energy behind the subwoofer system is desirable.

L-Acoustics provides specific documentation and presets for KS21 configurations. The appropriate configuration depends on the number and physical arrangement of the subwoofers.

Users should follow the current L-Acoustics configuration and preset documentation rather than creating an unsupported arrangement.

KS21 L-Vents

Like the A15, the KS21 uses L-Vents technology.

L-Acoustics states that its laminar venting technology reduces turbulence and port noise at high levels while increasing low-frequency efficiency. (L-Acoustics)

This is particularly relevant for a high-output subwoofer where air movement through the enclosure vents can otherwise contribute to unwanted turbulence noise.

The L-Vents form part of the KS21’s bass-reflex acoustic architecture.

KS21 Physical Construction

The KS21 is constructed for professional touring and production use.

L-Acoustics specifies premium-grade Baltic beech and birch plywood for the cabinet, a coated steel grille with acoustically neutral 3D fabric and high-grade steel rigging components with anti-corrosion coating. (L-Acoustics)

The KS21 is also specified with an IP55 rating.

Its construction is intended for demanding professional applications where equipment must be transported, installed and operated repeatedly.

KS21 Weight and Dimensions

Each KS21 weighs 49 kg / 108 lb according to L-Acoustics. (L-Acoustics)

The published dimensions are:

* Width: 764 mm
* Height: 571 mm
* Depth: 601 mm

These dimensions should be considered when planning transportation, storage and system deployment. (L-Acoustics)

Two KS21 enclosures therefore have a combined published net weight of approximately 98 kg, before packaging, covers, pallets or other transport materials are included.

A15 Physical Construction

The A15 uses a professional enclosure construction based on premium-grade Baltic beech and birch plywood.

The front grille uses coated steel with acoustically neutral 3D fabric, while the rigging components use high-grade steel with anti-corrosion coating. L-Acoustics specifies an IP55 rating for the A15. (L-Acoustics)

The construction is intended for professional live sound and touring applications.

Because the exact A15 variant in this set has not been specified, the precise weight and dimensions should be confirmed against the physical units being sold.

A15 Amplification

L-Acoustics lists the LA4X, LA8 and LA12X amplified controllers for the A15. (L-Acoustics)

These controllers provide the amplification and processing required to operate A15 systems using the appropriate L-Acoustics presets.

The correct amplifier configuration depends on the number of A15 and KS21 enclosures, desired system configuration and system requirements.

This listing includes the loudspeakers and subwoofers described above. Amplifiers, speaker cables and additional rigging accessories should not be assumed to be included unless specifically stated in the order.

KS21 Amplification

The KS21 is also designed to be amplified by L-Acoustics amplified controllers.

L-Acoustics lists LA4X, LA8 and LA12X as compatible controllers for KS21. (L-Acoustics)

This makes the A15 and KS21 combination suitable for systems based around L-Acoustics amplification and processing.

The correct amplifier allocation should be determined from the manufacturer’s current presets and the complete system configuration.

A15 KS21 for Live Events

The A15 KS21 Set can be used for a wide range of professional live sound applications.

Potential applications include:

* Concerts
* Festivals
* Corporate events
* Live entertainment
* DJ events
* Touring productions
* Outdoor events
* Indoor events
* Event production
* Professional rental
* Houses of worship
* Performing arts applications

The actual suitability of the system depends on venue size, audience capacity, desired SPL, coverage requirements and acoustic conditions.

Larger productions may require additional A15 or KS21 enclosures.

A15 KS21 for Rental Companies

For professional rental companies, the A15 KS21 combination provides a flexible inventory option.

The A15 can be used as the primary loudspeaker while the KS21 provides dedicated low-frequency reinforcement.

Because both products belong to the L-Acoustics ecosystem, they can be incorporated into appropriately designed systems using compatible amplification and processing.

Rental companies can also adapt the number of subwoofers and loudspeakers according to the requirements of different events.

A15 KS21 for Touring

Touring productions require equipment capable of repeated transportation and deployment.

The A15 and KS21 are both designed for professional production environments.

The A15 includes integrated handling and rigging features, while the KS21 provides external rigging interfaces and dedicated system accessories. (L-Acoustics)

For touring applications, transportation weight, vehicle capacity and loading procedures should be considered carefully.

The complete set contains four main loudspeaker enclosures, so appropriate transport and handling equipment should be used.

A15 KS21 for Corporate Events

The A15 KS21 Set can also be used for corporate events where professional sound reinforcement is required.

Applications can include product launches, conferences with live entertainment, gala events, awards ceremonies and corporate celebrations.

The A15 provides the primary sound reinforcement while the KS21 supplies extended low-frequency support for music and other program material.

The actual system configuration should be adapted to the room and audience requirements.

A15 KS21 for DJ Events

The combination can be particularly useful for DJ and electronic music applications where low-frequency performance is important.

The two KS21 subwoofers provide dedicated low-frequency reinforcement while the A15 loudspeakers reproduce the main program material.

The system can be configured according to venue size and desired output.

For larger events, additional subwoofers or main loudspeakers may be required.

A15 KS21 System Scalability

One of the advantages of the L-Acoustics A Series is scalability.

L-Acoustics describes the A15 as capable of scaling from high-output point-source applications to versatile line-source applications. (L-Acoustics)

The A15 can therefore form part of different system sizes depending on the production requirements.

The KS21 provides a scalable low-frequency component that can be deployed in different configurations.

The set offered here provides two A15 loudspeakers and two KS21 subwoofers as a starting system configuration.

A15 and KS21 Rigging

L-Acoustics provides dedicated rigging accessories for the A15 and KS21.

For A15, available system accessories include the A15-BUMP flying frame, M-BAR extension bar, A15-LIFT rigging element, A15-RIGBAR, A-MOUNT pole mount and A-TILT rigging element. (L-Acoustics)

The KS21 can be integrated with A15 using supported rigging equipment and configurations.

The manufacturer’s documentation confirms that combinations of KS21 and A15 can be flown or stacked to form a full-range system. (L-Acoustics)

Any flown configuration must follow the current L-Acoustics rigging documentation and applicable local safety requirements.

Professional L-Acoustics System

The A15 KS21 Set is designed around two established L-Acoustics product families.

The A15 belongs to the A Series, while the KS21 is part of the L-Acoustics subwoofer range.

The two products are specifically designed to work together, with KS21 extending the bandwidth of A15 systems. (L-Acoustics)

This makes the set relevant to professional users who want a coherent L-Acoustics system rather than combining unrelated loudspeaker brands or models.

€9,000 Per Set

The listed price for this package is:

€9,000 per set

Each set includes:

2 × L-Acoustics A15

2 × L-Acoustics KS21

The price applies to the complete four-enclosure package as described above.

Amplification, cables, rigging accessories, transport and other equipment are not included unless specifically stated in the final order.

Buyers should confirm the exact A15 version, physical condition, included accessories and availability before completing the purchase.

Condition and Inspection

If these are used L-Acoustics units, buyers should inspect the individual enclosures before purchase.

For the A15 units, inspection points should include:

* Cabinet condition
* Grille condition
* Front fabric
* SpeakON connectors
* Rigging hardware
* Handles
* Corner stops
* Ground runners
* Driver condition
* General cosmetic condition

For the KS21 units, inspection should include:

* Cabinet condition
* Grille and fabric
* Connector condition
* Rigging interfaces
* Driver performance
* Handles and handling points
* General cosmetic condition
* Signs of moisture exposure
* Previous repairs

The exact condition of the units should be confirmed from the inventory being offered.

Additional photographs and operational information can be provided to prospective buyers when required.

Who Is This A15 KS21 Set For?

This package can be suitable for:

* Professional sound rental companies
* Event production companies
* Touring companies
* Concert promoters
* Live sound engineers
* Corporate AV companies
* DJ production companies
* Venues
* Houses of worship
* System integrators
* Professional audio contractors
* Existing L-Acoustics users

The set is particularly relevant to customers who need a compact professional system combining full-range A15 output with dedicated KS21 low-frequency reinforcement.

L-Acoustics A15 KS21 Set for Sale

The L-Acoustics A15 KS21 Set provides a four-enclosure professional sound system consisting of two A15 loudspeakers and two KS21 subwoofers.

At €9,000 per set, it offers buyers a complete A15 and KS21 combination for professional sound reinforcement applications.

The A15 provides the primary loudspeaker component, while the KS21 extends the system’s low-frequency performance to a manufacturer-specified 29 Hz. (L-Acoustics)

This combination is suitable for professional event production, rental inventories, touring systems and other applications requiring high-output sound reinforcement.

Technical Specifications

A15

The A15 is available in Focus and Wide variants, so the exact specifications depend on the version supplied.

Type: 2-way passive 15-inch constant-curvature line source

Low-frequency transducer: 1 × 15-inch

High-frequency transducer: 1 × 3-inch diaphragm compression driver

Amplification: LA4X / LA8 / LA12X

Nominal impedance: 8 ohms

Directivity: Panflex horizontal options

A15 Focus bandwidth: 41 Hz to 20 kHz

A15 Focus maximum SPL: 144 dB

A15 Focus weight: 35 kg / 77 lb

A15 Wide bandwidth: 42 Hz to 20 kHz

A15 Wide maximum SPL: 141 dB

A15 Wide weight: 33 kg / 73 lb

These variant-specific specifications are taken from the official L-Acoustics A15 documentation. (L-Acoustics)

KS21

Type: High-power compact 21-inch subwoofer

Transducer: 1 × 21-inch neodymium cone driver

Low-frequency limit: 29 Hz

Maximum SPL: 138 dB

Directivity: Standard or cardioid

Acoustic load: Bass-reflex with L-Vents

Nominal impedance: 8 ohms

Amplification: LA4X / LA8 / LA12X

Connectors: 2 × 4-point terminal block with push-in connection

Dimensions: 764 × 571 × 601 mm

Weight: 49 kg / 108 lb

Protection: IP55

These specifications are verified against the official L-Acoustics KS21 product page. (L-Acoustics)

Frequently Asked Questions

What is included in the L-Acoustics A15 KS21 Set?

Each set includes 2 L-Acoustics A15 loudspeakers and 2 L-Acoustics KS21 subwoofers.

How much does the set cost?

The listed price is €9,000 per set.

How many A15 speakers are included?

Each set contains 2 A15 loudspeakers.

How many KS21 subwoofers are included?

Each set contains 2 KS21 subwoofers.

What is the KS21?

The KS21 is a high-power compact 21-inch L-Acoustics subwoofer designed to extend the bandwidth of A15 and A10 systems. (L-Acoustics)

What is the KS21 frequency limit?

L-Acoustics specifies a low-frequency limit of 29 Hz at -10 dB using the KS21_60 preset. (L-Acoustics)

What is the maximum SPL of the KS21?

The KS21 is specified at up to 138 dB maximum SPL under L-Acoustics’ stated measurement conditions. (L-Acoustics)

Is the KS21 compatible with the A15?

Yes. L-Acoustics specifically describes the KS21 as a subwoofer designed to extend A15 systems, and its documentation confirms A15 and KS21 configurations. (L-Acoustics)

Is the A15 available in different versions?

Yes. L-Acoustics currently lists A15 Focus and A15 Wide versions. (L-Acoustics)

What is the difference between A15 Focus and A15 Wide?

A15 Focus has 10° vertical directivity and a specified maximum SPL of 144 dB, while A15 Wide has 30° vertical directivity and a specified maximum SPL of 141 dB. (L-Acoustics)

What amplifier can power the A15?

L-Acoustics lists LA4X, LA8 and LA12X amplified controllers for A15. (L-Acoustics)

What amplifier can power the KS21?

L-Acoustics lists LA4X, LA8 and LA12X for KS21. (L-Acoustics)

Can the KS21 be used in cardioid configuration?

Yes. L-Acoustics specifies standard and cardioid configurations for KS21. (L-Acoustics)

Can A15 and KS21 be flown together?

L-Acoustics documentation states that combinations of KS21 and A15 can be flown or stacked to form a full-range system, using the appropriate manufacturer’s rigging configuration. (L-Acoustics)

Is amplification included?

Not according to the package contents supplied for this listing. The package is described as 2 A15 + 2 KS21. Amplifiers and additional accessories should only be considered included if specifically stated in the final order.

Is this suitable for rental companies?

The A15 KS21 combination is designed for professional sound reinforcement and can be used in rental and touring inventories, subject to the intended application and configuration.

Where can I buy the L-Acoustics A15 KS21 Set?

Contact Bsound Pro Audio to confirm availability, exact A15 version, condition, pricing and purchasing details.

Buy L-Acoustics A15 KS21 Set

Looking for a professional L-Acoustics A15 KS21 Set?

This package includes 2 × A15 and 2 × KS21 for €9,000 per set.

The combination is designed for professional sound reinforcement, with the A15 providing the primary loudspeaker system and the KS21 extending low-frequency performance down to 29 Hz according to L-Acoustics specifications. (L-Acoustics)

The exact A15 version should be confirmed before purchase because L-Acoustics offers both A15 Focus and A15 Wide.

Contact Bsound Pro Audio to check availability, condition and purchasing information.

Visit our Contact Us page to request more information.