FDS-318 - HARMAN Professional
Contents
1. VARIABLE CROSSOVER JMK 21st December 1999 C This equipment has been tested and found to comply with the following European and international Standards for Electromagnetic Compatibility and Electrical Safety Radiated Emissions EU EN55013 1990 Associated Equipment RF Immunity EU EN50082 1 1992 RF Immunity Fast Transients ESD Mains Disturbance EU EN61000 3 2 1995 Electrical Safety EU EN60065 1993 Radiated Emissions USA FCC part 15 Class B Electrical Safety USA UL813 ETL 1996 Commercial Audio Equipment Electrical Safety CAN UL813 ETLc 1996 Commercial Audio Equipment IMPORTANT SAFETY INFORMATION DO NOT REMOVE COVERS NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL THIS EQUIPMENT MUST BE EARTHED DO NOT EXPOSE TO RAIN OR MOISTURE ATTENTION RISQUE DE CHOC ELECTRIQUE CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN NE PAS ENLEVER NE PAS EXPOSER LA PLUIE NI AL HUMIDITE IT SHOULD NOT BE NECESSARY TO REMOVE ANY PROTECTIVE EARTH OR SIGNAL CABLE SHIELD CONNECTIONS TO PREVENT GROUND LOOPS ANY SUCH DISCONNECTIONS ARE OUTSIDE THE RECOMMENDED PRACTICE OF BSS AUDIO AND WILL RENDER ANY EMC OR SAFETY CERTIFICATION VOID For continued compliance with international EMC legislation ensure that all input and output cables are wired with the cable screen connected to Pin 1 of the XLR connectors and or the jack plug sleeve The input XLR Pin 1 and t2. PIWIH PINOT 91 9 IH PIWIH PIWIH PiWo1 PIWoT 07 sindino ous Auen om say pu 1 ana nano j 2oejes 17 E E gt AK imi T HE Var PTI THH 6 u 00 00 un pore EE x ey 2 E n j T 2 5 f 4 mu La 1 a a mn 4 a 1 a B Ti I H bi 55 LAS JETTA lt P N ac FH TI E functions Fig 11 1 Mode Using the FDS 318 11 2 Crossover The large control knobs on the left hand side of the front panel adjust the frequency adjustment 11 3 Output level alignment 11 4 Output MUTE switch 11 5 Output polanty reverse switch frequency of the fourth order Linkwitz Riley crossover filters They are arranged in stereo pairs to aid the setting up of like values on each channel In the 2 and 3 way modes the last two control knobs remain non functional The frequency range that is adjustable with each control is also modified according to whether the 2 WAY HI 2 WAY MID or 2 WAY LO mode is selected This range scaling of x10 or 10 is indicated on the front panel by the relevant adjacent LED The table in figure 11 1 indicated the respective function of each control dependant on the MODE selected They must be adjusted to suit the loudspeaker system being used
3. and connections Crossover frequency adjustment control Output level control Polarity reverse switch Mute switch Signal level indicators Select mode LED Rear panel switch LEDs Mains power fuse Main power switch 12 13 13 13 14 14 15 15 15 15 16 17 17 17 17 17 18 18 18 18 19 JDE VARIABL CROSSOVER Contents 10 10 Voltage selector switch 19 10 11 Output connections 19 10 12 Input connections 19 10 13 MONO LOW switch 20 10 14 CD EQ switch 20 10 15 SELECT MODE switch 20 11 0 Using the FDS 318 22 11 1 Selecting modes 27 11 2 Crossover frequency adjustment 25 113 Output level alignment 25 11 4 Output MUTE selector 25 11 5 Output polarity reverse selector 25 11 6 Output signal level indicators 26 11 7 CD Horn equalisation selector 26 11 8 MONO LO selector 26 12 0 Service Section 27 U 1 Chassis 0V Removal AN 142 Transient Suppressor Replacement 20 13 0 Specific ations 29 14 0 Warranty Information 30 Index User Notes Spare Parts Information FDS 318 Crossovers 10 Whatisa Crossover Crossovers are a necessary part of sound reinforcement systems because the loudspeaker drive unit which can produce clear reliable high SPL sound levels 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 necess
4. as incorrect settings can cause poor sound and will ultimately damage the loudspeakers Refer to the loudspeaker data sheet if the correct frequency is not known The eight smaller control knobs provide a range of adjustment of output level for each of the possible eight outputs and are arranged in stereo pairs to aid the setting up of like values on each channel They are designed to give an accurate and controlled range of 6dB about OdB the unity gain position When turned fully anticlockwise they continue to attenuate the output down to an infinity cut off The separate MUTE selector should be used when individual bands require muting It is recommended that the controls are first positioned at their OdB mark and small adjustments are then made to balance the system If attenuation greater than dB is required on any individual output you should suspect an imbalance somewhere else in the system and rectify the fault there rather than continue with the crossover controls excessively set Each output can be individually silenced by pressing the MUTE switch Press again to restore the output signal The number on the switch cap corresponds to the numbered output connectors on the rear panel Push button muting is an invaluable facility when setting up a sound system and avoids the necessity of using the output level controls which would upset previously made settings Each band of the FDS 318 includes a polarity switch Depressing it rever
5. as x10 and 10 indicates whether the printed frequency scale needs to be multiplied or divided by 10 for the correct value The control of this is determined by the SELECT MODE switch on the rear panel 10 2 Output level control Individual output control adjustable from 6dB of gain to OFF To ensure adequate resolution the first 12dB of control range covers approximately 60 of the available control rotation 10 3 Polanty reverse switch Individual polarity reverse selector switch Push to invert the polarity of the signal in that band 10 4 Mute switch Push to MUTE the signal in the selected band The number marked on the switch cap corresponds to the numbered output connectors on the rear panel 17 MULTI MODE VARIABLE CROSSOVER Controls and connections 10 5 Signal level indicators The SIG LED indicated that a signal is being received within that band and the PEAK LED warns of the possible onset of system overload The SIG LED will not light for signals below peak level of 20dB and the PEAK LED lights for signals in excess of 10dB This does not represent the maximum signal level within the FDS 318 which is 20dBv but rather that the sound system is being driven very hard For a more detailed explanation of this refer to section 11 6 10 6 Select mode LED These LEDs show which mode of operation has been selected by the rear panel SELECT MODE switch They also point toward the correc
6. carton and ALL relevant packing materials for use should the unit need returning In the event that damage has occurred please notify your dealer immediately so that a written claim to cover the damages can be initiated See Section 14 9 MULTI MODE VARIABLE CROSSOVER Getting to know the FDS 318 Fig 6 1 Front Panel MULTI MODE VARIABLE CROSSOVER 10 6 Fig 6 2 Rear Panel 10 9 10 15 10 11 FLOATING BALANCED OUTPUTS OUTPUT 5 CN AC Tam 4 d 1 e ell Em r um 9 aL vi o cu d od i BE 1 aa 10 8 10 14 10 ut MODE FDS 318 tuno 10 6 10 2 10 5 gt ki ir Bo ZZ i Jqi 1 Ah 290 8 o BU O WE d 38 All numbers in bubbles refer to Section numbers 11 Installation MULTI MODE VARIABLE CROSSOVER 7 0 Mechanical Installation Fig 7 1 Unit dimensions Fig 7 2 Rack dimensions 12 A vertical rack space of 1U 1 44 5 mm high is required Ventilation gaps are unnecessary See Figure 7 1 If the FDS 318 is likely to undergo extreme vibration through extensive road trucking and touring it is advisable to support the unit at the rear and or sides to lessen the stress on the front mounting flange The necessary support can generally be bought ready built as a rack tray As with any low level signal processing electro
7. extreme overvoltage the unit is protected against failure and the simple removal of these suppressors will allow the unit to be used again It is important that they are replaced as soon as possible to ensure continued protection The two VDRs are mounted on a small circuit board attached to the rear panel of the 120 240V selector switch Ensure that the unit is disconnected from the mains power before removing the suppressors Figure 12 1 indicates the location and specification for the suppressors Figure 12 1 Suppressor PCB MOUNTED BEHIND 120V 240V SELECTOR SWITCH location VDR1 amp VDR2 Transient suppressor TYPE MULLARD 2322 594 61312 MAX VOLTAGE 130V RMS 12 3 Intemal DC The internal DC fuses are located around the mains transformer and are labelled FS1 FS2 and FS3 fuse check The unit should be disconnected from the mains supply before the lid is removed WARNING Refer all servicing to qualified service personnel Risk of electric shock if the unit is opened BSS Audio accepts no responsibility for injury subsequent to opening of the unit 13 0 Input section Specifications Specifications 12k ohms electronically balanced 20dBu maximum input level via XLR 3 31 or equivalent Input CMMR better than 50dB 50Hz to 15kHz Output section Electronically balanced and floating capable of driving 26dBu into 600 ohms 26dBm or greater via XLR 3 32 or equivalent When unbalanced maximum
8. operate at any signal level up to 20dBu and will drive into loads of 600 ohms or greater Refer to figure 9 1 for the wiring convention Floating balanced output 4 Electronically balanced Input e e Er I TNR Pin I Ground Pin 1 Open circuit Pin 2 Hat Pin 2 Hot Fin 3 Cold Fin 1 Cold Whether your system is wired to Pin 2 hot or a Pin 3 hot convention is not important so long as the wiring to both input and output 3 pin XLR connectors is the same As is common with all other BSS Audio equipment of this type we follow the convention of ground goes forward with the signal Input cabling screening therefore needs to be derived from the signal source end as Pin 1 is ground lifted for the inputs It is recommended that you use high quality audio cable with 2 cores and a screen for low noise and reliability If the equipment driving the FDS 318 has only unbalanced outputs then you will need to add a wire jumper such that the screen connection on Pin 1 of the XLR is shorted to either Pin 2 OR Pin 3 depending on the wiring convention of the unbalanced equipment If the equipment being connected to the FDS 318 outputs have only unbalanced inputs then we recommend that you still use a balanced l e 2 core shielded cable The interconnecting cable should have its screen grounded by Pin 1 of the FDS 318 output and Pin 3 output should be connected to the unbalanced input OV
9. Input li ELECTROHICALY BALANCED INPUTS connections W The inputs are electronically balanced Maximum input is 20dBu in to 10Kohms Transformer balancing is NOT available is an internally fitted option Inputs 1 and 2 are used for the 4 and 3 way modes Inputs 1 2 3 and 4 are used for the 2 way modes 19 Controls and connections 10 13 MONO LOW h a ER En xii i VALUES TN LZ Lo 4 BH The MONO LOW switch operates in all stereo modes of operation and actively sums the signal information together on the LOW outputs Both left and right LOW outputs will then contain the summed LOW signal 10 14 CD EQ switch SELECT MODE WW HF rus au Tri OH 2d LUE RITE The CD EQ switch inserts constant directivity equalisation on all relevant outputs dependant on the mode selected Refer to the table in section 11 1 for more information x ELECT MODE 10 15 SELECT MODE switch 240 Fira p F d p The FDS 318 is designed to offer seven different modes of operation 4 way Two channels of 4 non overlapping frequency modes 4 way HF Two channels of 3 non overlapping frequency bands with an extra high pass parallel band running at a different selectable frequency This allows a sound system to utilise two different high frequency horn drivers which require
10. a different crossover frequency 4 way LF Two channels of 3 non overlapping frequency bands with an extra low pass parallel band running at a different selectable frequency This allows a 3 way sound system to operate with an optional sub bass system 3 way Two channels of 3 non overlapping frequency bands The unused upper control configured to operate as full range output buffers 2 way HI Four channels of 2 non overlapping frequency bands with the frequency control configured to operate over a 2kHz to 20kHz sweep range 20 FDS 318 2 way MID 2 way LO mi Og I Four channels of 2 non overlapping frequency bands with the frequency control configured to operate over a 200Hz to 2kHz sweep range Four channels of 2 non overlapping frequency bands with the frequency control configured to operate over a 20Hz to 200Hz sweep range 21 Using the FDS 318 11 0 22 Using 11 1 Selecting modes MODE VARIABLE CROSSOVER the FDS 318 The appropriate mode should be selected with the rear panel switch and this will be confirmed by the LED indicators on the front panel The table in figure 11 1 indicates the functions applicable to each front panel control 4 way Use this mode for a conventional stereo four way speaker system where each of the four bands operate over different non overlapping frequency ranges FreqiHzi 4 way HP Here the HI PASS front panel LED
11. able s ground earth wire is properly terminated it is important for personal safety as well as for proper control over the system grounding To lift the signal ground OV refer to section 12 1 The mains voltage selector switch located on the side of the unit provides a simple external adjustment to allow operation on all international AC power standards The allowable ranges for the supply voltage are 96VAC up to 132VAC on the 115V position and 192VAC up to 264VAC on the 230V position Outside these ranges the unit will not work satisfactorily if at all Voltages in excess of the maximum will probably cause damage Voltages below the minimum will cause the power supplies to drop out of regulation degrading the performance of the system 13 MULTI MODE VARIABLE CROSSOVER m Tr Connecting to power 14 Fig 8 1 Mainsfuse on rearpanel SELECT 3 We 4 WAY LP z WAY HP i lt lt E K L Du DW C 9 a WA A LO 8 3 AC Power The incoming mains power is fused within the FDS 318 by the fuse holder Fusing 8 4 Powering up mounted on the rear panel See figure 8 1 If it needs to be replaced it should be properly rated as 20mm 250V T200mA for 240V voltage setting or T250mA for 120V voltage setting It is most important for continued safety that this specification is strictly adhered to It is very unlikely that a fuse will blow during normal oper
12. an alternative to this procedure e Disconnect the mains power cord and remove the units top cover Locate the long green wire positioned at the rear of the unit which is terminated at the rear panel metalwork at a point in between the input and output connectors e Remove the end of this wire link from the chassis connection fold over and insulate fully e The signal 0V ground is now isolated for the chassis The other green wire terminated onto this chassis bolt is connecting the output XLR Pin 1 connections to chassis Under no circumstances is it recommended that this link is removed WARNING Refer all servicing to qualified service personnel Risk of electric shock if the unit is opened BSS Audio accepts no responsibility for injury subsequent to opening of the unit VARIABLE CROSSOVER CAUTION Important Notes SERVICE SECTION 122 Transient The primary of the mains transformer is protected against high voltage spike S interference by two voltage dependent resistors These provide a short circuit pressor to voltage peaks in excess of their maximum rating Replacement Should the unit be inadvertently connected to 3 phase line line voltages or to 240V when selected to 120V or any other incorrect voltage these suppressors are likely to fail in a protective short circuit mode This will be demonstrated by repeated mains fuse failure when powering up the unit Even in this case of
13. ary 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 set up 1 T FreqiHz Fig 1 2 Mono 3 wa y CHER CRANE Host Crossover set up ER Ik TUE FreqiHz MODE VARIABLE CROSSOVER 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 PASSIVE CROSSOVER LOS PSS FELTER LF BRITEE MME N HEI CUT TIE 1 CIE 3 MONTS EV resar THs DRIN ER LI ELE RS ACTIVE CROSSOVER MEHR P LF DRIVER IAN FE x im mos E UP TO 20 ABIMTIOMAL VHPLEEEFUEHBRS WF DRIER POWER AMP i ACTIVE CROSSOVERS ARE APPLICABLE TO MULTI AMPED SYSTEMS Some advantages of active crossovers are e Crossover frequenc
14. ation and must be treated with some caution as to the cause if it should do so One of the most likely reasons will be due to the incorrect setting of the voltage selector switch Another reason can be the inadvertent connection of line to line rather than line to neutral phase voltages when using a 3 phase power connection In either case the transient suppressors can become damaged and constantly blow replacement fuses You can rest assured that your unit has been protected from damage but the transient suppressors will need to be replaced as soon as possible for continued protection Refer to section 12 2 for information on this procedure When the FDS 318 is switched on with the power on off switch located on the rear panel the frontpanel LEDs showing the selected MODE will be illuminated This indicated that the internal power supply circuitry is functioning correctly Should an incorrect sequence of MODE LEDs be illuminated or the output signal LEDs become illuminated with no input signal present then an internal DC fuse may have failed Refer to section 12 3 for information on how to check the unit for this problem FDS 318 BEE m Audio connections 90 Audio Connections 9 1 Wiring convention Fig 9 1 XLR Plug Wiring 9 2 Balanced wiring 9 3 Unbalanced wiring The FDS 318 audio inputs are RFI filtered and electronically balanced with the outputs electronically balanced and floating They are designed to
15. ce TI MODE VARIABLE CROSSOVER 20 26 25 25 20 19 20 15 229 19 13 30 15 05 318 User Notes User Notes 34 I MODE VARIABLE CROSSOVER FDS 318 User Notes User Notes 36 I MODE VARIABLE CROSSOVER
16. ctor stays below 20dBu The PEAK LED lights if the output signal of the crossover approaches a level likely to overload the subsequent sound system which is set to be in excess of 10dBu The signal level appearing at the output connectors depends on the position of the LEVEL control Most power amplifiers however will be driven hard into clip at levels approaching 10dBu so under normal operating conditions this LED will NEVER flash Should they do so we recommend that you investigate the sound system gain structure the interconnecting cabling and the power amplifiers gain structure For amplifiers which do have an input sensitivity of 10dBu the PK LED will indicate when the system is driving at its hardest and its likely to flash during times of high peak power Selecting the rear panel switch CD EQ will insert a correcting equalisation to all relevant MID and HIGH outputs This is confirmed on the front panel by the appropriate LED The amplifier response of the equalisation is shown if figure 11 2 U em Tu IW FreqiHzl Modern constant directivity horns are often used in sound system as they have good control of dispersion and are often used in 2 way systems at low crossover frequencies However their output falls off progressively above 4kHz and to compensate for this extra boosting EQ is used The correcting EQ in the FDS 318 is designed to accurately match horn manufacturers specifications and restores
17. ground The Pin 2 output should be connected to the live input There should be no connection between the cable screen and OV chassis ground connection of the unbalanced equipment Strict adherence to this will help to eliminate potential ground loop hums by removing signal currents from the cable screen 15 Audio connections 16 9 4 Ground loop control ODE VARIABLE CROSSOVER Strict adherence to the wiring conventions noted above within a fully balanced signal system will give the best possible results with none of the problems normally associated with interconnected audio equipment Wherever possible cable screens should not be connected to any signal pin but rather left to perform a cable shielding function only Where it is not possible to control all of the external cabling it might become necessary to have internal electronic ground of your unit separated from the case safety ground Provision is made internally within the FDS 318 to separate these two grounds at a convenient point and reference to section 12 1 will explain the procedure Under no circumstances should the safety ground wire be removed from the mains AC power connector as an interim measure to achieve similar results 2 MULTI 1 Controls and connections 10 0 Controlsand connections 10 1 Crossover frequency adjustment control Left and right hand channels are adjustable separately The frequency scaling LEDs marked
18. he side chain input jack socket sleeve are connected to the chassis via a low value capacitor providing high immunity from ground loops whilst ensuring good EMC performance Please read We have written this manual with the aim of helping installers sound engineers and musicians alike to get the most out of the FDS 318 We recommend that you read this manual particularly the section on installation before attempting to operate the unit The manual is split into two main sections The first deals with quick reference information regarding the functions and operation of the unit while the second covers a more general background to use and application of the FDS 318 We welcome any comments or questions regarding the FDS 318 or other BSS products and you may contact us at the address or World Wide Web site given in the warranty section 2 FDS 31 Contents e P 2 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 8 1 8 2 8 3 0 4 9 0 9 1 9 2 9 3 9 4 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 Whatis a Crossover Contents The difference between Active and Passive Crossovers Other advantages The Linkwitz Riley advantage What is special about BSS Crossovers Unpac king Mechanical Installation Mains Power Connection Mains Power Voltage Setting AC Power Fusing Powering up Audio Connections Wiring convention Balanced wiring Unbalanced wiring Ground loop control Controls
19. ichannel up to four 2 way speaker system where each of the two bands operate over adjacent frequency ranges Select the 2 WAY HI mode when a crossover frequency is required within the range of 2kHz to 20kHz Select the 2 WAY MID mode when a crossover frequency is required within the range 200Hz to 2kHz Select the 2 WAY LO mode when a crossover frequency is required within the range 20Hz to 200Hz Jar 2kHz gt F gt HikHr J Way Mid 200Hz gt F lt 2kHz 2 VWiaw re F 2 Hz F FreqiHzi 23 LH 91 H 91 H 91 H e DE Sb Hn O1 03 um Clan eur oF ca jeuordo H 071 H o H o IH 94 H 07 H 07 H 01 IH o IH ADM Z uin sindino jew lex on sape pul JOU 1 1 9919S Aouenbael ISAOSSO1 di Ooss08 eA FOOLING Tid 1 1 MOT 405 SE 308 SL IH H PI PI v e jeuoy gt uny IH P W P W ADAE Aa nmn 9 nne jeuonydeo ndino IH H P W PA o o TX IH PN PUN 9 c x3 dl m 8 1 nre Aon Avena nne HX IH 1H PIW 9 01 IH IH PIN PIW 1 dH ua OH Gr Ac 3 9 1 ipe dion boi 1 q3jeuendo iH IH PIWIH
20. ies can be more readily altered to suit different driver horn combinations The level balance between the 2 or 3 frequency bands brought on by differences in driver and amplifier sensitivity can be readily trimmed Inside an active crossover unit line driving signal summing driver equalisation system muting and polarity phase reversal facilities can all be incorporated at small extra cost FDS 318 Crossover advantages 30 Otheradvantages Fig 3 1 Crossover Terminology The drive units in sound reinforcement systems utilising active crossovers benefit because Steep rolloffs are readily attainable The 24dB OCT rolloff in the BSS FDS 318 active crossover rapidly discharges out of band energy At one octave below the crossover point power received by the driver has dropped to less than 2 or 1 200th of full power The result Bad sound resulting from out of band resonances is effectively masked immediately beyond the crossover frequency See Figure 3 1 This contrasts markedly with passive crossovers where slopes in excess of 12dB OCT are rarely achieved and power rolloff is 4 times less rapid per octave URCOSSDVER PREG IIT ioe ooo FILTER WITH 5I WITH PIB H T SL f one frequency range is driven into clip drive units and horns in other frequency ranges are protected from damage and distortion is kept to a minimum e Direct connection of drive unit
21. illuminates to indicate the mode Use this mode when two high outputs are required such as when an additional long throw driver is needed to augment an existing 3 way system The crossover frequency of the extra output is independent and fully adjustable from the standard high output crossover point Freqi Hz 4 way LP Here the LO PASS front panel LED illuminates to indicate the mode Use this mode when two low outputs are required such as when temporary adding sub woofer loudspeakers to an existing 3 way system or when it is required or the sub woofers to be run in a parallel overlap mode with the normal low loudspeakers The crossover frequency for the extra output is independent and fully adjustable from the standard low output crossover point FDS 318 wuu n Freq Hz 3 Way Use this mode for a conventional stereo 3 way speaker system where each of the three bands operate over different non overlapping frequency ranges The extra two stereo pair outputs which do not form part of the crossover system are available as a full range buffer output operating over the whole frequency range of 20Hz to 20kHz These can be useful to drive small full range speaker systems in ancillary areas or act as line drivers with level and mute controls to drive a tape machine recording a show Full Ranpe 0 x Freqi Hz 2 way HI 2 way MID 2 way LO Use these modes for a conventional stereo or mult
22. nics it is best to avoid mounting the unit next to a strong source of magnetic radiation for example a high power amplifier to help keep residual noise levels in the system to a minimum mnm Es mni AS LA FILE CROGESOVER 482 60 Note All dimensions in mm Connecting to Power 8 0 Mains Power Connection 8 1 Mains Power 9 2 Voltage Setting WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT The wires in the mains lead are colour coded in accordance with the following code Earth As the colours of the wires in the mains lead may not correspond with the markings identifying the terminals in your plug proceed as follows The wire which is coloured Green and Yellow or Green must be connected to the terminal which is marked with the letter E or by the Earth signal or which is coloured Green and Yellow or Green The wire which is coloured Blue must be connected to the terminal labelled N or coloured Black or Blue The wire which is coloured Brown must be connected to the terminal labelled L or coloured Red or Brown Those units supplied to the North American market will have an integral moulded 3 pin connector which is provided to satisfy required local standards The FDS 318 must always be connected to a 3 wire grounded earthed AC outlet The rack framework is assumed to be connected to the same grounding circuit The unit must NOT be operated unless the power c
23. nt s the Linkwitz Riley alignment provides for more coherent sound dispersion it provides on axis symmetrical radiation patterns See Figure 4 2 Invisible slopes The absence of electrical phase difference close to the crossover frequency helps to make the steep 24dB OCT slope effectively inaudible Response peaks and dips are negligible and inaudible given the correct polarity phasing of the speaker connections The same is not true of the shallower 6 12 or 18dB OCT rates or rolloff in other crossovers Radiation Pattern at Crossover Frequency showing excellent on axis symmetry FDS 318 BSS Crossovers Unpacking 5 0 Whatis special about BSS Crossovers The FDS 318 is an electronic crossover offering many modes of operation to suit professional sound systems and also to support equipment rental companies in reducing crossover inventory by having an easily re configurable loudspeaker system controller The FDS 318 fully supports stereo 3 way stereo 4 way or four separate channels of 2 way operation all in a 1U package The internal switching of circuitry is automatically controlled by information held within a digital PROM memory device such that the operator needs no additional knowledge other than the mode the currently required As with other BSS crossover products output sections not used within a given configuration are always available as full range buffer drivers An important part of any elec
24. ormation 14 0 30 Warranty Information IMPORTANT This unit is warranted by BSS Audio to the original end user purchaser against defects in workmanship and the materials used in its manufacture for a period of one year from the date of shipment to the end user Faults arising from misuse unauthorised modifications or accidents are not covered under this warranty No other warranty is expressed or implied If the unit is faulty it should be sent in its original packaging to the supplier or your local authorised BSS Audio dealer with shipping prepaid You should include a statement listing the faults found The unit s serial number must be quoted in all correspondence relating to a claim We recommend that you record your purchase information here for future reference Dealer Name Dealer Address Post Zip Code Dealer Phone No Dealer Contact Name Invoice Receipt No Date of Purchase Unit Serial Number In keeping with our policy of continued improvement BSS Audio reserves the right to alter specifications without prior notice The FDS 318 was designed and developed by BSS Audio Hertfordshire England Phone 44 0 1707 660667 Fax 44 0 1707 660755 World Wide Web address http www bss co uk Index B Balanced wiring C CD EQ switch CD Horn equalisation switch Chassis 0V Removal Connections audio input output Controls crossover frequency adjustment Mute switch output level pola
25. output level is 20dBu into 600 ohms or greater System performance Frequency Response THD noise Output noise Output level control Signal metering Modes Mono Lo Crossover filters Filter type Sweep range 3 Way 2 way Hi 2 way Mid 2 way Lo CD Horn EQ Power Voltage Dimension Weight 4 way Subsonic high pass filter 3dB at 15Hz 6dB Oct Ultrasonic low pass filter 3dB at 30KHz 12dB Oct Better than 0 0596 20Hz 20kHz any level up to 18dBu Better than 85dBu 22Hz to 20kHz 6dB gain to OFF Calibrated OdB gain marker Signal present LED 20dBu at output connectors Signal overload LED 10dBu at output connectors Stereo 4 way stereo 3 way four channels 2 way Stereo 4 way includes options for extra overlapping high pass and extra overlapping low pass outputs Sums the output of left and right LOW outputs when selected Stereo modes only Fourth order 24dB Oct Linkwitz Riley adjustable over 10 1 sweep range Mode switching includes x10 and 10 scaling Lo LoMid 200Hz 2kHz LoMid HiMid 200Hz 2kHz HiMid Hi 1k25 12k5Hz Lo Mid 200Hz 2kHz Mid Hi 200Hz 2kHz Lo Hi 2kHz 20kHz Lo Hi 200Hz 2kHz Lo Hi 20Hz 200Hz First order rising 6dB Oct 3dB at 3k5Hz AC 40VA 50 60Hz 96V 132V or 192V 264V selectable externally Anchored 2M power cord 44 5 x 483 x 288mm 1 75 x 19 x 11 3 4 2kg Net 5 2kg packed in shipping carton 29 VARIABLE CROSSOVER Warranty Inf
26. rity reverse switch signal level indicators Crossover frequency adjustment 17 25 Crossovers Active v Passive advantages D Dimensions E Farthing procedure F Front Panel Fuse AC Power Mains power G Ground loop control Input connections Installation Invisible slopes 15 20 26 27 15 19 19 17 17 17 17 18 OS 12 13 10 14 18 19 12 L LED rear panel switch select mode Linkwitz Riley M Main power switch Mains fuse Mains power requirements Modes 2 way HI 2 way MID 2 way LO 3 way 4 way 4 way HP 4 way LP MONO LO switch MONO LOW switch Mute switch O Output level alignment Output level control Output MUTE switch Output signal level indicators P Polarity reverse switch Power switch Powering up R Rear Panel Rear panel switch LED S Select mode LED SELECT MODE switch Service section Signal level indicators Specifications Switch CD EQ mains power Index 18 18 19 18 13 22 23 23 22 22 22 26 20 17 25 17 25 26 17 19 14 10 18 18 20 27 18 29 20 26 19 31 Index 32 si H F i ER MONO LO Output MUTE Output polarity reverse select mode Voltage selector T Transient Suppressor Replacement U Unbalanced wiring Unpacking User Notes V Voltage selector switch Voltage settings W Warranty Info Wiring convention Z Zero Phase differen
27. s to the power amplifier cut out loss of damping factor normally inevitable thanks to the appreciable resistance of the inductors in passive crossovers Amplifiers benefit too from the use of active crossovers As they do not handle a full range signal clipping produces far less harmonic and intermodulation distortion The results Momentary overdrive sounds less harsh Also the amplifiers dynamic headroom is generally higher and heatsink temperatures can run lower WODE VARIABLE CROSSOVER Linkwitz Riley Alignment 4 0 The Linkwitz Riley advantage Fig 4 1 Linkwitz Rile y filte rs Fig 4 2 Radiation Pattem Frequency showing excellent on axis symmetry There is an additional set of advantages exclusive to active crossovers made by BSS and other manufactures using the Linkwitz Riley alignment See Figure 4 1 LEY EI FLAT TAGE AI CROS A EE Pi Y Zero Phase difference at crossover The phase difference between drivers operating in adjacent frequency bands is close to zero degrees at the crossover frequency Phase alignment in this manner prevents interactive effects i e High and Low drivers fighting each other over the narrow band of frequencies around the crossover point which is where the units from two adjacent frequency ranges are contributing near equal amounts of sound pressure More predictable sound dispersion By providing in phase summation at the crossover poi
28. ses REV the polarity or phasing of the signal coming from the related output Should the sound system exhibit a cancellation or dip in its frequency response at or around the crossover frequency this could be due to a reverse wired loudspeaker driver a reverse wired connecting lead or a power amplifier wired to a different input balanced connection This is easily corrected by pushing the REV switch for the particular output A similar situation could arise when a loudspeaker system is designed to receive a reverse polarity signal for one of its component parts In either case the REV function can be readily selected and the decision to which position is required can be judged either by careful listening to program music or by using a Pink noise source and real time analyser RTA If switching does not improve the sound and the drop is appreciable the cause is undoubtedly acoustic and linked to the drive unit spacing and cabinet design 25 Using the FDS 318 11 6 Output signal Each output has two LED indicators showing the level of signal within each level indicators 11 7 CD Hom equalisation switch 26 Fig 11 2 CD Hom EQ response 11 8 MONO LO switch and at the output connector The lower SIG LED operates to show that a signal is being received Steady illumination means high drive levels and periodic flashing indicates a moderate drive level The LED will not light if the peak signal level at the output conne
29. t control knob function as this varied dependant on the mode selected 10 7 Rear panel switch LEDs These LEDs show the status of the CD EQ and MONO LOW switches on the rear panel 10 8 Mains power fuse T 5 The mains power fuse is 20mm long and rated T250mA for 120V settings and T200mA for 240V settings For continued protection ALWAYS replace this fuse with the correct value 18 FDS 318 _wutri MopE VA 10 9 Main power mp switch F FAY A WA f mem oo i m d A ER Wie 8 LO PA T USE FUSE Lacy Turns the FDS 318 on or off 10 10 Voltage se lec to r SW h a TET rai IBI ESI CORRECT Pos ied FUSE 5 ATED FOR i pem m VOLTAGE ZEE Tri USE FLEX HERDER LOCATED CIN i arl ECT THE PANEL Located the side of the unit this switch allows operation in the following regions 96 132V or 192 264V 50 60Hz AC 10 11 Output FLOATING BALANCED OUTPUTS will 7 CEBIT 5 Wu sil N d connections 9 5 The outputs are electronically balanced and floating Maximum output is 20dBu into 600 ohms or greater Transformer balancing is NOT available as an internally fitted option and so the BSS AR 204 balancing unit should be specified if required 10 12
30. the high frequency output Care should be exercised in the use of this function as it can be potentially dangerous if used on systems not utilising Constant Directivity components The table in figure 11 1 shows which outputs have the option dependent on the mode selected Because human hearing is insensitive to the location of low frequency sound sources below 100Hz stereo operation is normally dispensed with for sub woofer systems Selecting the MONO LO switch on the rear panel of the FDS 318 automatically sums the left and right hand inputs signals for the low frequencies The table in figure XX indicates which outputs are affected for each mode and a front panel LED lights to confirm the function is selected This function does not operate in the 2 way modes FDS 318 CAUTION Important Notes SERVICE SECTION 12 0 Service Section 12 1 Chassis OV The FDS 318 has the signal Ov ground connected to the metal chassis which Removal in turn is connected to the safety ground In the unlikely event that you need to remove this link or if you need to add a small impedance to reduce earth loop currents then proceed as follows Since both the audio inputs and outputs are wired fully balanced we strongly recommend that you fully recheck all wiring for correctness prior to proceeding Under no circumstances should the incoming ground wire be disconnected from the power line cord or from the internal chassis connection as
31. tronic crossover is the filter type and todays industry standard series Butterworth filters pioneered by BSS Audio since 1979 is available in the FDS 318 in the form of the fourth order Linkwitz Riley design These provide the necessary in phase outputs and steep 24dB Oct slopes required to give the best constant voltage summation and minimal lobing for non coincidental drivers These filters are fully sweepable by accurate front panel controls which are also automatically reconfigured depedant upon the mode of operation selected Some of the features available within the FDS 318 are e Stereo 4 way stereo 3 way four channels of 2 way in a 1U unit e Linkwitz Riley fourth order filters with sweepable frequency selection Digitally controlled mode selection offering extended range selection and features Electronically balanced inputs and floating balanced outputs e Constant directivity equalisation externally selectable for all HIGH outputs e Polarity reverse mute selection and signal LED indication for each output MONO LOW selection for all stereo modes Comprehensive mode selection indication identifying the function of each control Full range buffer outputs on all non used section 60 Unpacking As part of BSS system of quality control this product is carefully inspected before packing to ensure flawless appearance After unpacking the unit please inspect for any physical damage and retain the shipping
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