Кроссовер bss fds 360
Кроссовер FDS 360 (995$) позволяет осуществлять разделение на две полосы в стереорежиме или на три-четыре полосы в моно. На каждой полосе есть лимитеры. Частоты раздела, тип и крутизна характеристик фильтров задаются с помощью специальных плат с элементами фильтров. На передней панели есть регуляторы уровня, кнопки и светодиодные индикаторы заглушения, переключатели полярности, трехсегментные светодиодные индикаторы уровня сигнала (относительно порога срабатывания лимитера) для каждой полосы, светодиодные индикаторы режима работы полос, кнопка и светодиодный индикатор суммирования в моно низкочастотной составляющей (при работе в стерео и совместной работе нескольких таких устройств), три регулятора фазы полос относительно друг друга, выключатель питания.
На задней панели есть держатель предохранителя, селектор сетевого напряжения, несъемный сетевой кабель, два симметричных входа (XLR), трехпозиционный переключатель режима работы (двухполосный стерео, трехполосный моно или четырехполосный моно), четыре несимметричных выхода (XLR), четыре блока по пять DIP-переключателей (задают порог срабатывания лимитеров в каждой полосе), колодка со вспомогательными контактами (куда также выведены посылы-возвраты каждой из четырех полос и прочее). Входы имеют защиту от ультразвука и инфразвука (согласно руководству пользователя, можно впаять дополнительные радиодетали в предусмотренные отверстия на плате устройства и изменить тем самым частоту среза фильтра верхних частот).
Платы разделения частот FDS 360 F (22$) в количестве трех штук (соответствующие желаемым частотам разделения) устанавливаются под крышкой устройства. Платы могут поставляться как готовыми, так и предназначенными для самостоятельной сборки.
Кроме того, на каждой полосе возможна эквализация, для чего следует установить плату FDS 360 D (104$) с четырьмя блоками, состоящими из фильтра нижних частот и параметрического эквалайзера, или карту FDS 360 E (104$), отличающуюся от FDS 360 D тем, что два ее блока представляют собой фильтры типа «полка».
Кроссовер выполнен в однорэковом корпусе, габариты 482 x 44 x 228 мм, масса в упаковке 4,5 кг.
| Мониторинг цен по объявлениям |
FDS 360 . Средняя 500.
600 (24.10.2004), 450 (14.11.2004), 450 (16.11.2004).
Приводятся цены по объявлениям, ранее размещенным на сайте МО в разделе Продажа. Полный список здесь.
Источник
BSS fds360 schematic
14 October 1996
This equipment has been tested and found to comply with the following European Standards for Electromagnetic Compatibility:
(RF Immunity, Fast Transients and ESD)
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.
What is a Crossover?
2.0 The difference between Active and
The Linkwitz-Riley advantage
5.0 What is special about BSS
Mains Power Connection
Mono Low Switch
Limiter Threshold Switch
Card Location for Four Way System
Card Location for Three Way System
Card Location for Stereo Two Way System
Rear Barrier Strip
Auto Mute Cancel
Limiter Threshold Reference
Band Insertion Points
Modes of Operation
Mono Three Way with Extra Full Range
Operating a Sub-Woofer system from an
Mono Low between separate units
Adjustment for A
Adjustment for B
System Diagrams and Descriptions 25
15Hz Subsonic Filter Change
Filters and Frequency Tables
Full Range Frequency Card
BSS Supported Options
FDS-360 Equalisation Options
Application of the FDS-360D to a system
FDS-360 E Installation
Electronic/Chassis Earth Link
Transient Suppressor Replacement 39
Spare Parts Information
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
Fig 1.2 Mono 3-way
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.
• Crossover frequencies can be more readily altered to suit different driverhorn 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.
3.0 Other advantages
The drive-units in sound reinforcement systems utilising active crossovers benefit because:
• Steep rolloffs are readily attainable. The -24dB/OCT rolloff in the BSS FDS360 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 ½ % (or 1/200th) of full power . The result: Bad sound resulting from out- of-band resonances are 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.
Fig 3.1 Crossover Terminology
• If 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.
• Direct connection of drive-units to the power amplifier cuts 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. Because 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.
4.0 The Linkwitz-Riley advantage
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 ).
Fig 4.1 Linkwitz-Riley
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; this 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 point(s), the Linkwitz-Riley alignment provides for more cogent 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.
Fig 4.2 Radiation Pattern Frequency showing excellent onaxis symmetry
5.0 What is special about BSS Crossovers?
The FDS-360 is an electronic crossover system, and incorporates all the latest technology and facilities that are required for todays high powered loudspeaker systems. This frequency dividing system ( FDS ) is substantially more than a basic crossover, combining a high degree of sophistication which enables accurate control of loudspeaker power, dispersion and acoustical summation around the critical crossover region.
The FDS-360 features the following:
• Stereo two-way mode, or switchable three/four way mono mode.
• Separate frequency band limiters matched to the precise band of frequencies controlled.
• Separate polarity switching for each band.
• LED signal level monitoring.
• Band insertion points for interfacing external equalisation and time delay units.
• Band-edge phase adjustment allowing 360 degrees of control.
• Crossover filter programming via plug-in frequency cards allowing any frequency, choice of 12/18/24dB/OCT slopes and filter responses to be specified. 24dB/OCT Linkwitz-Riley responses are supplied as standard.
• Internal equalisation option.
Every FDS-360 is manufactured to the highest professional standards with a robust steel case, high quality circuit boards and ICs, and high quality components to provide reliable performance under the most demanding conditions of the global sound-reinforcement environment. In common with all other BSS equipment, the FDS-360 is subject to stringent quality control procedures throughout the manufacturing process. Components are tested against demanding acceptance criteria. Every completed unit is tested both by measurement and in a listening test carried out by trained audio professionals. To positively ensure reliability, all units are burnt-in for fifty hours, before being tested.
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 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.
Getting to know the FDS-360
Fig 6.1 Front Panel
Fig 6.2 Rear Panel
10.0
11.6
9.0
All numbers in bubbles refer to Section numbers.
7.0 Mechanical Installation
A vertical rack space of 1U (1¾» / 10½mm) deep is required. Ventilation gaps are unnecessary ( See Figure 7.1 ).
If the FDS-360 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 electronics, 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.
Fig 7.1 Unit dimensions.
Connecting to Power
8.0 Mains Power Connection
Fig 8.1 Mains fuse on rear panel.
Voltage: The FDS-360 operates on supply voltages between 95 and 125V AC. It must not be plugged into 220, 230 and 240V AC outlets. If the unit is accidentally connected to an AC supply giving in excess of 132V AC, refer to section 23 , ( See Figure 8.1 ).
Frequency: Both 60Hz and 50Hz are acceptable.
Grounding: The FDS-360 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 cables ground (‘earth’) wire is properly terminated — it is important for personal safety, as well as for proper control over the system grounding. If the electronic 0V has to be separated from the chassis and mains power earth, refer to section 23 .
Connections: The AC power cable has a moulded 3-pin utility plug attached to the free end to facilitate the correct and proper connections.
AC Power Fusing: The incoming line power passes through a 200mA (for 240V only) anti-surge (‘T’) fuse, accessible from the rear panel (The fuse is rated at 250mA for 120V). If the fuse blows without good reason, refer to section 23 . Always replace with an identical 20mm x 5mm T rated fuse for continued protection from equipment damage and fire. Also see section 22 for information on replacing blown transient suppressors (if applicable).
Power ON: Before turning on the power, it is worth checking that the three frequency cards are installed correctly. Loosen the captive screw securing the small cover plate on the lid of the unit, and inspect the cards. The slope and frequency information is recorded on each of these cards, and it must be ensured that all cards are fitted, regardless of whether they are required. Refer to sections 12 & 18 for more information concerning these cards.
The FDS-360 outputs are instantaneously muted at power OFF. At switch on, a delay prevents turn-off thumps propagating through the sound system.
9.0 Input Connections
9.1 XLR Plugs. The two input signals are 10k ohm active balanced on a standard 3 pin
‘female’ XLR which will accept levels up to +20dBv. The wiring convention is as follows: ( See Figure 9.1a ):
Pin 1: No connection (the shield of the drain wire can be terminated here if desired).
Pin 2: Signal ‘-‘, out of phase or ‘COLD’. Pin 3: Signal ‘+’, in phase or ‘HOT’.
For unbalanced sources ( See figure 9.1b ):
Pin 1: Leave open, or link to pin 2.
Pin 2: Shield, braid, or screen wire.
Pin 3: Signal ‘+’ or ‘HOT’ (inner core).
There is no internal ground connection to Pin 1 of the female XLR to avoid possible interconnection earth loops. The input signal cable shield must therefore be tied to ground, or signal 0V, at the source end.
Fig 9.1 XLR Plug Wiring
10.0 Output Connections
10.1 XLR Plugs The four signal outputs are DC blocked low impedance unbalanced from a standard 3 pin male XLR and are designed to drive up to +20dBv into 600
ohms or greater. The wiring convention is as follows:
Pin 1: Connects to shield, screen or drain wire.
Pin 2: ‘-‘, cold or ‘out of phase’ output.
Pin 3: ‘+’, hot or ‘in phase’ output.
If the amplifiers you are feeding have unbalanced (single ended) inputs, but are fed from standard pin to pin XLR cables (See above), simply link the cable at the crossover end as follows:
Pin 1: Connects to shield or screen wire.
Pin 2: Link to Pin 1.
Pin 3: Connects to the inner ‘hot’ or live core.
Unbalanced transmission is not recommended for connections to distant equipment , but is generally acceptable for local connections within the rack, or to an adjacent rack.
Technicians note: As with a traditional transformer balanced output, either output phase (+ or -, hot or cold) can be linked to ground to ‘unbalance the line’ without upsetting the operation of the unit. As with a transformer, output level remains the same in the unbalanced mode.
Источник
