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Table of Contents
Related Manuals for L-Acoustics ARCS
Summary of Contents for L-Acoustics ARCS
- Page 1 Version 2 February 2003 L-ACOUSTICS ARCS OPERATOR MANUAL...
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Page 2: Foreword
Thank you for purchasing the ARCS sound reinforcement system. This manual is intended to provide you with the information you require to install and operate ARCS in a wide variety of professional sound reinforcement applications. Specific information and recommendations are included regarding system design, sound design and installation procedures. -
Page 3: Table Of Contents
4.6 USING ARCS WITH SUBWOOFERS ......................34 A) COMBINING ARCS WITH SUBWOOFERS..................34 B) GROUND STACKED SYSTEMS ......................35 C) SEPARATE FLOWN ARCS ARRAY WITH GROUND STACKED SUBWOOFERS ......36 5. INSTALLATION PROCEDURES .......................37 5.1 INSTALLATION OF A SINGLE ROW FLOWN SYSTEM ................37 5.2 INSTALLATION OF A DOUBLE ROW FLOWN SYSTEM ................ -
Page 4: List Of Figures
Table 10: L-ACOUSTICS Subwoofer Specification Summary................. 34 Table 11: Subwoofer and Low Section Processing for ARCS 3-Way Presets ..........35 Table 12: ARCBUMP Pick Point Hole Number versus Tilt Angle for 2, 3 or 4 ARCS ........46 Table 13: ARCS Rigging Reference Chart......................47 L-ACOUSTICS ARCS Manual V2.0... -
Page 5: Introduction
In this case, the Haas effect is exploited and delay lines can also be introduced to provide proper localization. This is the distributed sound reinforcement, or multiple sound source approach and the L-ACOUSTICS MTD or XT lines of coaxial loudspeakers is highly suited to this type of sound design. -
Page 6: C) The Arcs ® Sound Reinforcement System
ARCS enclosure and, as a result, the wavefront radiated at high frequencies by an ARCS array is continuous with an arc's shape that is equal to the N*22.5° (where N is the number of enclosures). For example, four ARCS enclosures provide a horizontal coverage angle of 90°. -
Page 7: Figure 1: Conventional Horn Array Versus An Array Of Arcs Dosc Waveguides
DOSC waveguide, the angle of each enclosure is 22.5°. At lower frequencies, the size of the ARCS enclosure allows for perfect coupling due to the size of wavelengths below 800 Hz, i.e., the distance between acoustic centers of adjacent sources is always less than half a wavelength over the entire low section operating bandwidth, thus satisfying WST Condition #2. -
Page 8: The Arcs System
(4) BUMP3 Flying bumper for rigging an ARCS array. Weight is 3.8 kg (8.4 lbs). One BUMP3 is required to fly 2 or 4 cabinets. Two BUMP3 and one LIFTBAR are required to fly 1, 3, 4, 6 or 8 enclosures. -
Page 9: Figure 3: Arcs System Block Diagram
Figure 3: ARCS System Block Diagram L-ACOUSTICS ARCS Manual V2.0 2/13/2003... -
Page 10: Figure 4: Arcs System Parts And Accessories
ARCPLA ARCS ARCOUPL BUMP3 ARCSCOV LIFTBAR ARCSTRAP ARCBUMP F-LINK CABLE DO.7 F-CABLE DO7 Figure 4: ARCS System Parts and Accessories L-ACOUSTICS ARCS Manual V2.0 2/13/2003... -
Page 11: Arcs Specifications
+40°, -20°. The HF DOSC waveguide itself is constructed of injection molded polyurethane and is acoustically resonant-free. The ARCS enclosure is constructed of 18 mm Baltic birch plywood and all joints are rabbeted, screwed and glued. The front dolly is of the same construction and is contoured to secure and protect ARCS during transportation. -
Page 12: Arcs Accessories
ARCPLA is attached by mating the two positioning studs on the front baffle of the ARCS enclosure with the corresponding holes of the ARCPLA then locking the dolly to the enclosure using two O-ring snap-pins. -
Page 13: Figure 8: Arcoupl
(up to 4), whereas two BUMP3 and one LIFTBAR are required for flying an odd number or for more than 4 enclosures (up to 8). For larger configurations where ARCS is flown in the normal (vertical) orientation, there should be no more than 4 ARCS enclosures (vertically or horizontally) supported by a single BUMP3. -
Page 14: Figure 10: Examples Of Bump3 Requirements For 4 And 5 Element Arcs Arrays
ARCBUMP is a rigging bumper that allows ARCS to be flown in the horizontal orientation. For rigging up to 3 ARCS enclosures, single point hangs can be performed using the rigging points available on the central spreader bar section of ARCBUMP. For flying 4 ARCS enclosures horizontally, a bridled hang should be performed using the exterior points on the sides of the ARCBUMP frame. -
Page 15: Figure 12: Arcstrap
ARCS enclosures (bottom ARCOUPL bars) and bottom row ARCS enclosures (top ARCOUPL bars). Locking nuts with cotter pin safeties are then used to secure ARCSTRAP. Figure 12: ARCSTRAP Figure 13: Example of ARCSTRAP, BUMP3, LIFTBAR Requirements for a 2 row x 4 element ARCS Array L-ACOUSTICS ARCS Manual V2.0 2/13/2003... -
Page 16: Powering Arcs
2. POWERING ARCS It is important that power amplifiers with sufficient power are used to power ARCS since headroom is much less likely to damage loudspeaker components than amplifier clipping. Apart from normal standards regarding construction, protection, cooling and damping factor that are expected of any... -
Page 17: Table 2A: Recommended Power Amplification And Mls Switch Settings For Arcs Low Section
L-ACOUSTICS LA48a can be used for powering 3 ARCS in parallel. Alternatively, for operating 3 ARCS in parallel, the LA24a can be used to power the HI section while the LA48a is used for the LOW section. -
Page 18: Figure 14: Mls Switches On The Rear Panel Of La24A And La48A Amplifiers
Figure 14: MLS switches on the rear panel of LA24a and LA48a amplifiers Table 3: L-ACOUSTICS LA24a and LA48a Power Amplifier Specifications L-ACOUSTICS LA 24a POWER MATRIX MLS SWITCH SETTING LOAD CONFIGURATION -5 dB -4 dB -2 dB 0 dB... -
Page 19: Connectors And Cables
4 mm conductor cross-section (11 gauge). The SP25 cable can therefore be used for 25 meter cable runs to power a 4 ohm load (2 ARCS in parallel) with a damping factor greater than 20. 3. ARCS CONTROL AND PROCESSING... -
Page 20: General Description Of Arcs Presets
3W presets are provided for use of ARCS with either SB218 or dV-SUB subwoofers. The subwoofer channel is low pass filtered at 80 Hz and the ARCS low channel is high pass filtered at 80 Hz. Presets are optimized for a standard 2:1 cabinet ratio of ARCS : SB218 or dV-SUB (for example, 2:1, 4:2, 8:4) and as a starting point, output channel gains are: sub +3, low 0, high -8. -
Page 21: Guidelines Regarding System Protection
W and assuming 32 dB amplifier gain, these power ratings correspond to limit thresholds of -1 dBu (100 W) and +5 dBu (400 W). As standard, the ARCS HF limiter threshold is set to +2 dBu (3 dB less than the peak power handling). Standard thresholds should be suitable for most applications however... -
Page 22: Arcs Preset Libraries
3.4 ARCS PRESET LIBRARIES All 2-way presets are configured in stereo 3-way mode, i.e., channel A and B Low/High outputs are on output channels 2 / 3 and 5 / 6, respectively. This means that drive racks do not require recabling when changing from 3-way to 2-way presets. -
Page 23: Table 5: Xta Dp226 Presets
L-ACOUSTICS V7 0902 PRESETS for XTA DP 226 PRESET NAME PGM TYPE OUT 1 (Source) OUT 2 (Source) OUT 3 (Source) OUT 4 (Source) OUT 5 (Source) OUT 6 (Source) ARCS 2W LO 3-way stereo FULL (A) ARCS LOW (A) -
Page 24: Table 6: Xta Dp224 Presets
L-ACOUSTICS V7 0902 PRESETS for XTA DP 224 PRESET NAME PGM TYPE OUT 1 (Source) OUT 2 (Source) OUT 3 (Source) OUT 4 (Source) ARCS 2W LO 2-way stereo ARCS LO (A) ARCS HI (A) ARCS LO (B) ARCS HI (B) -
Page 25: Table 7: Bss 366 Omnidrive Compact Plus Presets
115XT HI (A) 115XT LOW (B) 115XT HI (B) 115XT LOW (C) 115XT HI (C) *L-ACOUSTICS V7 PRESETS MUST BE USED WITH BSS 366 VERSION 1.10 FIRMWARE (OR HIGHER) Table 7: BSS 366 Omnidrive Compact Plus Presets L-ACOUSTICS ARCS Manual V2.0 2/13/2003... -
Page 26: Table 8: Bss 334 Minidrive Presets
L-ACOUSTICS V7 0103 PRESETS for BSS 334 MINIDRIVE PRESET NAME PGM TYPE OUT 1 (Source) OUT 2 (Source) OUT 3 (Source) OUT 4 (Source) ARCS 2W LO 2-way stereo ARCS LO (A) ARCS HI (A) ARCS LO (B) ARCS HI (B) -
Page 27: Table 9: Bss 336 Minidrive Presets
L-ACOUSTICS V7 0103 PRESETS for BSS 336 MINIDRIVE PRESET NAME PGM TYPE OUT 1 (Source) OUT 2 (Source) OUT 3 (Source) OUT 4 (Source) OUT 5 (Source) OUT 6 (Source) ARCS 2W LO 3(A)+3(B) FULL (A) ARCS LOW (A) ARCS HI (A) -
Page 28: Sound Design
The larger the array, the lower the frequency where directivity control is obtained. The horizontal coverage is N x 22.5° (where N is the number of ARCS) and the vertical coverage of a single row array is the same as for a single enclosure regardless of the number of ARCS in the array (i.e., 60°... -
Page 29: Double Row Arrays
FOH mix position (or approximately 30 metres from the system as a reference point). 4.2 ARRAY AIMING The first task is to map the coverage of an ARCS array in the vertical plane (i.e., section cutview) in order to see how it matches the audience area to be covered. L-ACOUSTICS' proprietary ARRAY software is useful for this purpose –... -
Page 30: Figure 15: Array Cutview Simulation Of An Arcs Installation For Theatrical Sound Reinforcement
Figure 15: ARRAY Cutview simulation of an ARCS installation for theatrical sound reinforcement. The flown and ground stacked ARCS arrays are both inverted to provide +20/-40 degree coverage. As an alternative to ARRAY, CAD tools for AUTOCAD are available for representing ARCS horizontal and vertical coverage: L-ACOUSTICS ARCS Manual V2.0... -
Page 31: Monitor Side-Fill
2 SB218s provide a good footprint for stacking up to 3 ARCS. Note: When ARCS is stacked on top of a 2 high horizontal stack of SB218 subwoofers, the overall height is 1.92 meters. When ARCS is stacked on top of SB218s oriented vertically, the overall height is 2.12 meters. -
Page 32: Complementary Fill
(flown or stacked), stereo front-fill, offstage fill or delay system applications. The number of potential uses for ARCS as a fill enclosure is only limited by your imagination. The following recommendations give some commonly used examples. In all cases, proper time alignment of fill systems with respect to the main L/R FOH system is essential for obtaining optimum results. -
Page 33: Flown/Stacked Centre Fill
The trim height and tilt of the ARCS center fill array depends on the closest distance to be covered which is in turn determined by the distance to the first rows of the audience area. L-ACOUSTICS' ARRAY software is very useful for predicting vertical coverage requirements (see ARRAY AIMING), allowing the sound designer to quickly determine the necessary trim height and ARCS array tilt angle. -
Page 34: Delay Systems
Figure 19: ARRAY cutview simulation of an ARCS FOH system with delays. The main L/R system consists of 8- 10 ARCS per side in a double row configuration with 4 ARCS per side ground stacked for stereo infill. Delay rings are located at 45 and 75 meters and the exact number of delay positions per ring will depend on the plan view of the audience and the amount of horizontal coverage required. -
Page 35: Using Arcs With Subwoofers
ARCS system (separate auxiliary send from the console) while in other cases, the subwoofers are used as a low frequency extension of the array and are driven with the same signal in 3-way mode. -
Page 36: B) Ground Stacked Systems
3W presets have an 80 Hz LR24 low pass filter for the subwoofers with a complimentary 80 Hz LR24 high pass filter for the ARCS low section. These presets are recommended for either stacked or flown ARCS/ground stacked subwoofer applications and are suitable for either sub drive via aux send or 3- way mode. -
Page 37: C) Separate Flown Arcs Array With Ground Stacked Subwoofers
If more low frequency energy is desired from the flown ARCS system, 3WX presets can be used with reference to Table 11 for guidelines concerning subwoofer polarity depending on how subwoofers are processed. -
Page 38: Installation Procedures
Always install two ARCOUPL coupling bars between adjacent enclosures (top and bottom) To fly an array of 2 or 4 ARCS enclosures, one BUMP3 is required. To fly an array of 1, 3, 5, 6, 7 or 8 ARCS enclosures, two BUMP3 and one LIFTBAR are required. - Page 39 (1) ARCS plus required accessories for flying a single (2) Close up detail of rigging accessories (6 row of 4 enclosures ARCOUPL, 1 BUMP3 plus shackles) (3) Enclosures located in position and in the desired (4) Front dolleys removed (note: logos oriented orientation (refer to rear jack plates –...
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Page 40: Figure 22: Rigging Procedure For A 4 Enclosure Arcs Array
(13) Front locking nut and bolt assembly installed with Rigging Reference Chart for hole selection to saftey, pick point selected on BUMP3 provide the desired tilt angle for the array) Figure 22: Rigging Procedure for a 4 Enclosure ARCS Array L-ACOUSTICS ARCS Manual V2.0 2/13/2003... -
Page 41: Figure 23: Rigging Procedure For A 3 Enclosure Arcs Array
(1) 2 x BUMP3 and 1 x LIFTBAR required for rigging 1, 3 or 5 ARCS (2) 2 x ARCOUPL installed on the bottom of the array, 2 x BUMP3 installed on top (3) The final flown assembly (refer to the Rigging Reference Chart for hole selection to provide the... -
Page 42: Installation Of A Double Row Flown System
Note: For a 2 x 2 element ARCS array, only one BUMP3 is necessary. For a 2 x 3 element ARCS array, one LIFTBAR should be used along with two BUMP3 (placed between enclosures 1 & 2 and 2 & 3). - Page 43 (5) Front detail of ARCSTRAP attachment (6) Rear detail of ARCSTRAP attachment (7) BUMP3 slides into position from the rear (8) 2 x BUMP3 required (9) LIFTBAR attached to 2 x BUMP3 (refer to Rigging Reference Chart for hole selection) L-ACOUSTICS ARCS Manual V2.0 2/13/2003...
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Page 44: Arcbump Installation
For offstage fill applications the 40° coverage angle is normally oriented in the offstage direction. For rigging up to 3 ARCS enclosures horizontally, single point hangs can be performed using the rigging points available on the central spreader bar section of ARCBUMP. For flying 4 ARCS enclosures horizontally, a bridled hang should be performed using the exterior points on the sides of the ARCBUMP frame. - Page 45 (7) Safety steels are used to secure ARCBUMP to (8) Front view the array (front and rear, top and bottom) (9) Side view (note: shackle attached to central (10) Rear view spreader bar section for single point hang) L-ACOUSTICS ARCS Manual V2.0 2/13/2003...
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Page 46: Figure 25: Arcbump Rigging Procedure For A 3 Enclosure Horizontal Arcs Array
(14) The final flown assembly (rear view) (13) The final flown assembly (front view) Figure 25: ARCBUMP rigging procedure for a 3 enclosure horizontal ARCS array L-ACOUSTICS ARCS Manual V2.0 2/13/2003... -
Page 47: Safety Rules
Table 12: ARCBUMP Pick Point Hole Number versus Tilt Angle for 2, 3 or 4 ARCS (hole #1 = rear pick point, ARCBUMP serial number plate towards the front) Hole 2 ARCS 3 ARCS 4 ARCS * Number Tilt Angle (deg) -
Page 48: Table 13: Arcs Rigging Reference Chart
Table 13: ARCS Rigging Reference Chart L-ACOUSTICS ARCS Manual V2.0 13-02-03... -
Page 49: Arcs System Operation
/ return snake multicore system). For 6 channel units (XTA DP226 or BSS 336, 366) outputs 1, 2, 3 correspond to SUB, ARCS LOW, ARCS HIGH for input A while output channels 4, 5, 6 correspond to SUB, ARCS LOW, ARCS HIGH for input B. -
Page 50: Spare Parts
WINMLS, SMAART, SPECTRAFOO, TEF or MLSSA measurement systems. Refer to the on-axis amplitude/frequency response in order to determine if the response of your ARCS enclosure is within specification. In addition, a response sweep using a sine wave generator is useful for checking for coil rubs, buzzes, air leaks or other undesirable mechanical vibrations as part of the periodic quality control procedure. -
Page 51: Specifications
Black epoxy perforated steel with acoustically transparent foam Features: Integrated flying hardware, handles Dimensions : 820 mm (Height) x 440 mm (Front) x 190 mm (Rear) x 652 mm (Depth) (32.3" x 17.3" x 7.5" x 25.7”) Weight: 57 kg (125.7 lbs) L-ACOUSTICS ARCS Manual V2.0 13-02-03... -
Page 52: Figure 26: Arcs Line Drawing
Figure 26: ARCS line drawing L-ACOUSTICS ARCS Manual V2.0 13-02-03...
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