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FDS 360
User Manual




1
V3.0 JMK 14 October 1996




This equipment has been tested and found to comply with the following European Standards for
Electromagnetic Compatibility:
Emission Specification: EN55013 (1990) (Associated equipment)
Immunity Specification: EN50082/1 (1992) (RF Immunity, Fast Transients and ESD)
Mains Disturbance: EN61000/3/2 (1995)
For continued compliance ensure that all input and output cables are wired with cable screen connected to Pin
1 of the XLR. The input XLR Pin 1 on BSS equipment is generally connected to chassis via a capacitor to
prevent ground loops whilst ensuring good EMC compatibility.




We have written this manual with the aim of helping installers, sound engineers and consultants alike get to
grips with the FDS-360 and obtain its maximum capability.
If you are new to BSS products, we recommend that you begin at the start of the manual. If, however, you are
already familiar with the intended application, and just want to get the unit installed without delay, then
follow the highlighted sections.
We welcome any comments or questions regarding the FDS-360 or other BSS products, and you may contact us
at the address or World Wide Web site given in the warranty section.
2
Contents



Contents
1.0 What is a Crossover? 5
2.0 The difference between Active and
Passive Crossovers 6
3.0 Other advantages 7
4.0 The Linkwitz-Riley advantage 8
5.0 What is special about BSS
Crossovers? 9
6.0 Unpacking 9
7.0 Mechanical Installation 12
8.0 Mains Power Connection 13
9.0 Input Connections 14
9.1 XLR Plugs. 14

10.0 Output Connections 14
10.1 XLR Plugs 14

11.0 Controls 16
11.1 Mode Switch 16
11.2 Level Control 16
11.3 Mute Switch 16
11.4 Polarity Switch 17
11.5 Mono Low Switch 17
11.6 Phase Control 17
11.7 Limiter Threshold Switch 18
11.8 Signal LEDs 18

12.0 Frequency Cards 19
Card Location for Four Way System 19
Card Location for Three Way System 19
Card Location for Stereo Two Way System 19

13.0 Rear Barrier Strip 20
13.1 Limiter Cancel 20
13.2 Auto Mute Cancel 20
13.3 Limiter Threshold Reference 20
13.4 Band Insertion Points 20



3
Contents



14.0 Modes of Operation 21
14.1 Mono Three Way with Extra Full Range
Buffered Output 21
14.2 Operating a Sub-Woofer system from an
Effects Send 21
14.3 Mono Low between separate units 21

15.0 Limiter Adjustment 22
Adjustment for A 22
Adjustment for B 22

16.0 Phase Adjustment 24
17.0 System Diagrams and Descriptions 25
17.1 Full unit 25
17.2 15Hz Subsonic Filter Change 25

18.0 Filters and Frequency Tables 27
18.1 Standard Filters 27
18.2 Full Range Frequency Card 27

19.0 BSS Supported Options 30
19.1 Output Balancing 30
19.2 Security Cover 30

20.0 FDS-360 Equalisation Options 31
20.1 Introduction 31
20.2 FDS-360D Installation 31
20.3 Circuit Description 31
20.4 Filter Design 33
20.5 Application Notes 35
20.6 Application of the FDS-360D to a system 36
20.7 FDS-360 E Installation 38

21.0 Electronic/Chassis Earth Link 39
22.0 Transient Suppressor Replacement 39
23.0 Troubleshooting 40
24.0 Glossary 41
25.0 Specifications 44
26.0 Warranty Information 45
Index 49
User Notes 51
4 Spare Parts Information
Crossovers



1.0 What is a Crossover?
Crossovers are a necessary part of sound reinforcement systems because the
loudspeaker drive-unit which can produce clear reliable high SPL (sound
level) over the full audio bandwidth has yet to be invented. All real-world
drive units work best when they are driven over a limited band of frequencies,
for example: Low, Mid and High.
Any crossover aims to provide the division of the audio band necessary, so
each drive unit receives only the frequencies it is designed to handle. In a
high power, high performance sound system, the crossover should also reject
unsuitable frequencies to avoid damage and poor quality sound.



Fig 1.1 Stereo 2-way
Crossover setup




Fig 1.2 Mono 3-way
Crossover setup




5
Active and Passive Crossovers



2.0 The difference between Active and
Passive Crossovers
Passive crossovers divide the frequency spectrum after the signal has been
raised to a high power level. They are generally heavy, bulky and inefficient.
Active crossovers utilise ICs and transistors, and divide the frequency
spectrum at line levels, immediately ahead of the amplifiers (See Figure 2.1).
An active crossover does the same job as a passive crossover, but with more
precision, flexibility, efficiency, and quality.


Fig 2.1