KS28
user manual (EN)
Document reference: KS28 user manual (EN) version 1.0
Distribution date: April 4, 2016
© 2016 L-Acoustics. All rights reserved.
No part of this publication may be reproduced or transmitted in any form or by any means without the express written consent of the publisher.
Contents
Safety................................................................................................................................................................ 4
Instructions................................................................................................................................................4
Symbols................................................................................................................................................... 4
Welcome........................................................................................................................................................... 5
KS28 reference subwoofer.........................................................................................................................5
System components.............................................................................................................................................6
Loudspeaker configurations..................................................................................................................................7
KS28 in standard configuration..................................................................................................................7
KS28 in cardioid configuration.................................................................................................................. 8
Loudspeaker connection...................................................................................................................................... 9
Connectors............................................................................................................................................... 9
Connection to LA12X.............................................................................................................................. 10
Preset description..............................................................................................................................................12
Recommendation for speaker cables...................................................................................................................13
Maintenance.................................................................................................................................................... 14
Repair kits..............................................................................................................................................14
KR SECUGRL...............................................................................................................................14
G03229..................................................................................................................................... 14
Disassembly and Reassembly procedures.................................................................................................. 15
D/R - GRILL.................................................................................................................................. 16
D/R - LF LOUDSPEAKER................................................................................................................ 19
Illustrations....................................................................................................................................................... 22
Loudspeaker cables.................................................................................................................................22
KS28 specifications...........................................................................................................................................23
3
Safety
Safety
Instructions
Inspect the product before operation.
If any sign of defect or damage is detected, immediately withdraw the product from use for maintenance.
Never incorporate equipment or accessories not approved by L-Acoustics.
Read all the related PRODUCT INFORMATION documents shipped with the products before exploiting the system.
Do not store the product on an unstable cart, stand, tripod, bracket, or table.
Beware of sound levels.
Do not stay within close proximity of loudspeakers in operation.
Loudspeaker systems are capable of producing very high sound pressure levels (SPL) which can instantaneously lead to permanent hearing damage to performers, production crew and audience members. Hearing damage can also occur at moderate level with prolonged exposure to sound.
Check the applicable laws and regulations relating to maximum sound levels and exposure times.
Read the RIGGING MANUAL before installing the system.
Use the rigging accessories described in the rigging manual and follow the associated procedures.
Read the maintenance section of this document before servicing the product.
Do not expose the product to extreme conditions.
Do not expose the product to rain or sea spray.
Do not expose the product to moisture (mist, steam, humidity, condensation…) or excessive heat (direct sun, radiator…) for a long period of time.
Contact L-Acoustics for advanced maintenance.
Refer to the product warranty.
Symbols
The following symbols are used in this document:
This symbol indicates a potential risk of harm to an individual or damage to the product.
It can also notify the user about instructions that must be strictly followed to ensure safe installation or operation of the product.
This symbol notifies the user about instructions that must be strictly followed to ensure proper installation or operation of the product.
This symbol notifies the user about complementary information or optional instructions.
KS28 user manual (EN) version 1.0
4
5
Welcome
Welcome
Thank you for purchasing the L-Acoustics KS28.
This document contains essential information on using the system properly. Carefully read this document in order to become familiar with the system.
As part of a continuous evolution of techniques and standards, L-Acoustics reserves the right to
change the specifications of its products and the content of its document without prior notice. Please check
www.l-acoustics.com
on a regular basis to download the latest document and software updates.
KS28 reference subwoofer
The KS28 is a reference subwoofer designed to extend the frequency response of large format systems. The KS28 features two high excursion, 18’’ direct radiating transducers mounted in a bass-reflex tuned enclosure. The optimized L-
Vents laminar vented port reduce turbulence and port noise at high levels while also increasing LF efficiency.
The KS28 operates from 25 Hz. The excursion capability of the transducer, combined with L-Vents contributes to deliver a high SPL, with low distortion. The KS28 can offer standard or cardioid directivity, by combining physical deployment and the suitable preset.
The KS28 is the first L-Acoustics enclosure to fully utilize the LA12X amplified controller power. The LA12X ensures advanced crossover functions, linearization and L-Drive protection of the transducers. Its onboard library offers standard and cardioid presets, each available with two low-pass filters to accommodate various coupling conditions and LF contour requirements.
The KS28 cabinet is assembled with birch and beech plywood panels. The use of panels optimized for thickness and combined with stiffeners gives the KS28 maximized internal volume, mechanical integrity and a low weight of 79 kg. It feature six ergonomic handles for a solid grip and efficient handling. Bottom and side runners ensure safe stacking. A two-point suspension system is flush-mounted into the cabinet.
The KS28 is the ideal companion to large format systems in stacked or flown deployments. KS28 can significantly boost the LF extension and contour of line sources.
The KS28 can be stacked horizontally or vertically in standard or cardioid arrangements. With KS28-BUMP, KS28 can be flown in vertical arrays of standard or cardioid arrangements, up to 16 units.
KS28 user manual (EN) version 1.0
System components
System components
Loudspeaker enclosures
KS28 flyable subwoofer 2 × 18"
Powering and driving system
LA12X
LA-RAK II
L-Case amplified controller with DSP, preset library and networking capabilities touring rack containing three LA12X, LA-POWER II for power distribution and LA-PANEL II for audio and network distribution protection case for L-Acoustics 2U electronics
Refer to the LA12X user manual for operating instructions.
Loudspeaker cables
SP cables 4-point speakON loudspeaker cables (4 mm² gauge)
SP cables come in four sizes: SP.7 (0.7 m/2.3 ft), SP5 (5 m/16.4 ft), SP10 (10 m/32.8 ft) and
SP25 (25 m/82 ft)
SP-Y1
DO cables
DOSUB-LA8 breakout cable for two passive enclosures (2.5 mm² gauge) provided with a CC4FP adapter
4-point speakON to 2 × 2-point speakON
8-point PA-COM loudspeaker cables (4 mm² gauge)
DO cables come in three sizes: DO.7 (0.7 m/2.3 ft), DO10 (10 m/32.8 ft) and DO25
(25 m/82 ft) breakout cable for four passive enclosures (4 mm² gauge)
8-point PA-COM to 4 × 2-point speakON
DO3WFILL breakout cable for one 2-way active enclosure and two passive enclosures (4 mm² gauge)
8-point PA-COM to 1 x 4-point speakON and 2 x 2-point speakON
Information about the connection of the enclosures to the LA amplifiers is given in this document.
Refer to the LA12X user manual for detailed instructions about the whole cabling scheme, including modulation cables and network.
Rigging elements
Rigging elements or procedures are not presented in this document.
Refer to the KS28 rigging manual.
Software applications
Soundvision
LA Network
Manager
3D acoustical and mechanical modeling software software for remote control and monitoring of amplified controllers
Refer to the LA Network Manager video tutorial.
Refer to the Soundvision help.
KS28 user manual (EN) version 1.0
6
7
Loudspeaker configurations
Loudspeaker configurations
KS28 in standard configuration
Deployed in a standard configuration, a KS28 system operates with an omnidirectional directivity pattern over the nominal bandwidth of the KS28 enclosure.
The [KS28_60] and [KS28_100] factory presets provide the subwoofer system with an upper frequency limit at 60 Hz and 100 Hz respectively in order to optimize the acoustic coupling with a main full-range system.
The KS28 subwoofers can only be driven by the LA12X amplified controller.
vertical on-end block stacked upright horizontal
Preset
Low frequency limit (-10 dB)
[KS28_60]
25 Hz
[KS28_100]
Delay values
When combining a line source with subwoofers, delays may have to be added to the presets.
Refer to the Preset Guide to obtain the pre-alignment delay values.
Grouping subwoofers
Place the subwoofer enclosures side by side. If not possible, the maximum distance between two adjacent acoustic centers must be 2.8 m or 1.7 m if the upper frequency limit of the subwoofer system is at 60 Hz or
100 Hz, respectively.
KS28 user manual (EN) version 1.0
Loudspeaker configurations
KS28 in cardioid configuration
Deployed in a cardioid configuration, a KS28 system produces a rear SPL rejection. The deployment consists of an array of four KS28 with one reversed element, i.e. turned towards the rear. Refer to the Cardioid Configurations technical bulletin for more information.
The [KS28_60_C] and [KS28_100_C] factory presets provide the subwoofer system with an upper frequency limit at
60 Hz and 100 Hz respectively in order to optimize the acoustic coupling with a main full-range system.
The KS28 subwoofers can only be driven by the LA12X amplified controller.
vertical on-end stacked upright block
Preset
Low frequency limit (-10 dB)
[KS28_60_C]
25 Hz
[KS28_100_C]
Delay values
When combining a line source with subwoofers, delays may have to be added to the presets.
Refer to the Preset Guide to obtain the pre-alignment delay values.
Grouping subwoofers
Place the subwoofer enclosures side by side. If not possible, the maximum distance between two adjacent acoustic centers must be 2.8 m or 1.7 m if the upper frequency limit of the subwoofer system is at 60 Hz or
100 Hz, respectively.
KS28 user manual (EN) version 1.0
8
Loudspeaker connection
Loudspeaker connection
Connectors
The KS28 is equipped with one 4-point speakON connector.
KS28
Internal pinout for L-ACOUSTICS subwoofers
speakON points 1 +
Transducer connectors LF +
1 -
LF -
IN
KS28
Weight: 79 kg / 174 lb
1k = IN k
1 - = IN -
Znom. = 4 #
SAFE USE:
16 KS28
SAFETY WITH SOUNDVISION SOFTWARE
USE ONLY WITH L-ACOUSTICS AMPLIFIED CONTROLLERS
Read manual and safety instructions before use
Made in France
European Community
2 +
Not linked
2 -
Not linked
9 KS28 user manual (EN) version 1.0
Loudspeaker connection
Connection to LA12X
Maximum number of enclosures per LA12X
enclosure
KS28 max enclosures in parallel
1
Impedance load
KS28
1 enclosure: 4 Ω
Connecting subwoofers
Cardioid configuration
Connect the reversed subwoofer(s) to OUT 1 to use the cardioid preset.
Subwoofer on speakON output - SP + SP-Y1 max enclosures per controller
4
OUT1/OUT2
SP
OUT3/OUT4
CH1 (OUT1)
SP-Y1
CC4FP
CH2 (OUT2) same as OUT1/OUT2
Subwoofer on CA-COM output - DO + DOSUB-LA8
CA-COM
DO
SP1 (OUT1)
SP2 (OUT2)
SP3 (OUT3)
SP4 (OUT4)
KS28 user manual (EN) version 1.0
10
Connecting a 2-way active enclosure with subwoofers
2-way active enclosure and subwoofers on CA-COM output - DO + DO3WFILL
SUB1 (OUT1)
CA-COM
DO
SUB2 (OUT2)
2WAY (OUT3/4)
2-way active
Loudspeaker connection
11 KS28 user manual (EN) version 1.0
Preset description
Preset description
[KS28_60] [KS28_100] outputs
OUT 1
OUT 2
OUT 3
OUT 4
channels
SB
SB
SB
SB
[KS28_60_C] [KS28_100_C] loudspeaker elements
SR
SB
SB
SB
outputs
OUT 1
OUT 2
OUT 3
OUT 4
routing
IN A
IN A
IN A
IN A
gain
0 dB
0 dB
0 dB
0 dB
channels routing
SR IN A
SB
SB
SB
gain
0 dB
delay
0 ms
0 ms
0 ms
0 ms
polarity
+
+
+
+
mute
ON
ON
ON
ON
delay
0 ms
polarity mute
+ ON
ON
ON
ON
KS28 user manual (EN) version 1.0
12
Recommendation for speaker cables
Recommendation for speaker cables
Follow the recommended maximum length for loudspeaker cables to ensure minimal SPL attenuation.
Cable quality and resistance
Only use high-quality fully insulated speaker cables made of stranded copper wire.
Use cables with a gauge offering low resistance per unit length and keep the cables as short as possible.
The table below provides the recommended maximum length for loudspeaker cables depending on the cable gauge and on the impedance load connected to the amplifier.
cable gauge
mm
2
2.5
4
6
SWG
15
13
11
AWG
13
11
9
recommended maximum length
8 Ω load 4 Ω load
m
30
50
74 ft
100
160
240 m
15
25
37 ft
50
80
120
2.7 Ω load
m
10
17
25 ft
33
53
80
For your installation projects, you can use the more detailed L-ACOUSTICS calculation tool to evaluate cable length and gauge based on the type and number of enclosures connected. The calculation tool is available on our website:
http://www.l-acoustics.com/installation-outils-de-calcul-1367.html
13 KS28 user manual (EN) version 1.0
Maintenance
Maintenance
Repair kits
KR SECUGRL
Kit safety O-rings for front grill
CP SECUGRL
code
CP SECUGRL
MC OUTGRL
G03229
KR 18'' speaker
MC OUTGRL
description
grill safety O-ring grill safety tool
qty
100
1
code
17545
CV TC630I-2
17545 CV TC630I-2
description
18" speaker - 8 ohms
M6x30 Tuflok coated hex socket head cap screw
qty
1
8
KS28 user manual (EN) version 1.0
14
Disassembly and Reassembly procedures
In order to operate, follow the order outlined here.
START
D/R - KS28 GRILL
D/R - KS28 LF LOUDSPEAKER
G03229
Maintenance
15 KS28 user manual (EN) version 1.0
Maintenance
D/R - GRILL
How to remove and reassemble the KS28 grill.
Tools
Name
electric screwdriver with torque selector
5 mm hex bit
MC OUTGRL (provided) -
-
Reference
EH.605
Pre-requisite
The enclosure is placed on its rear face, as illustrated.
-
-
Distributor
Disassembly
Procedure
1. Loosen the captive grill screw.
Use the 5 mm hex bit.
KS28 user manual (EN) version 1.0
16
2. Slide the grill to remove it.
If necessary, pull down the safety O-ring.
Reassembly
Procedure
1. Position the grill starting with the top.
Maintenance
17 KS28 user manual (EN) version 1.0
Maintenance
2. With the MC OUTGRL, stretch the O-ring and pull it above the captive screw.
3. Secure the grill with the captive screw.
Use the 5 mm hex bit and set the torque to 3 Nm.
KS28 user manual (EN) version 1.0
18
D/R - LF LOUDSPEAKER
How to remove and replace the KS28 LF speaker.
Tools
Name
electric screwdriver with torque selector
5 mm hex bit
-
Reference
EH.605
Pre-requisite
Grill disassembled.
The enclosure is placed on its rear face, as illustrated.
See
GRILL
(p.16).
-
Distributor
FACOM
Maintenance
Disassembly
Procedure
1. Remove the screws securing the speaker.
Use the 5 mm hex bit.
19 KS28 user manual (EN) version 1.0
Maintenance
2. Disconnect the cables and carefully remove the loudspeaker.
3. Remove the loudspeaker gasket.
KS28 user manual (EN) version 1.0
20
Reassembly
About this task
For safety reasons, always use the new screws and spare parts provided in the KR.
Procedure
1. Stick the gasket on the cabinet.
Use the screw inserts as reference points.
Maintenance
2. Position the loudspeaker and connect the loudspeaker cables.
3. Secure the loudspeaker with the CV TC630I-2 screws.
Use the 5 mm hex bit and set the torque to 5 Nm.
21 KS28 user manual (EN) version 1.0
Illustrations
Illustrations
Loudspeaker cables
SP.7
SP5
SP10
SP25
DO.7
DO10
DO25
DO3WFILL
DOSUB-LA8
SP-Y1
4-point speakON loudspeaker cable (0.7 m / 2.3 ft)
4-point speakON loudspeaker cable (5 m / 16.4 ft)
4-point speakON loudspeaker cable (10 m / 32.8 ft)
4-point speakON loudspeaker cable (25 m / 82 ft)
8-point PA-COM loudspeaker cable (0.7 m / 2.3 ft)
8-point PA-COM loudspeaker cable (10 m / 32.8 ft)
8-point PA-COM loudspeaker cable (25 m / 82 ft) breakout cable for one 2-way active enclosure and two passive enclosures breakout cable for four passive enclosures breakout cable for two passive enclosures
KS28 user manual (EN) version 1.0
22
KS28 specifications
KS28 specifications
Description
Low frequency limit (-10 dB)
Maximum SPL
1
Directivity
Transducers
Acoustical load
Nominal impedance
Connectors
Rigging and handling
Weight (net)
Cabinet
Front
Rigging components
Finish
flyable subwoofer 2 × 18", amplified by LA12X
25 Hz ([KS28_100])
143 dB ([KS28_100]) standard or cardioid
2 x 18" neodymium, aluminium die cast basket bass-reflex, L-Vents
4 Ω
4-point speakON flush-fitting 2-point rigging system
6 ergonomic handles
2 ground runners
8 side runners
79 kg / 174 lb first grade Baltic beech and birch plywood steel grill with anti-corrosion coating acoustically neutral 3D fabric high grade steel dark grey brown Pantone 426C
1
Peak level at 1 m under half space conditions using pink noise with crest factor 4 (preset specified in brackets).
KS28 dimensions
1351 mm / 53.2 in
702 mm / 27.6 in
1340 mm / 52.8 in
23 KS28 user manual (EN) version 1.0
