System Design for Live Sound Essay

Proposal of a Sound System AUD407 Advanced Audio System Design Table of Contents Overview3 Site Assessment4 Environmental Analysis5 System Design Requirements5 The System8 Figure 1:Line Array Configuration8 Figure 2:Jsub Frequency Map9 Figure 3:Line Array Analysis10 Foldback12 Figure 4:Foldback Speaker Placement12 Mixer/Desk13 Signal Flow13 Sound Reinforcement Analysis14 “Rock” Band14 Choir14 FOH14 Amp15 Foldback15 Stage Box/Mixer15 Overall Equipment List16 Power19 Figure 5:Power Distribution19 Watts Per Person FOH (peak)20 Conclusion20 Bibliography21 APPENDIX22

Overview The event in which this proposal is catered for is a ‘carols by candlelight’ evening. The intended audience is comprised of children, adults, seniors and all people in-between. It is to be held at a local sporting ground with audience attendance numbers in the region of 2000 people. Site Assessment Below is an aerial map of the proposed event. One can see that this location works well. With easy accessibility to all necessary facilities and ample parking space, there are no glaring problems. The power generator will be located next to the back stage area.

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Lighting can easily be setup on each corner of the field. Lighting is already present in the adjacent buildings allowing for easy navigation to the field area. The only slight issue that may arise is from people traveling from parking area 2 to the field. To ensure nobody gets lost, signs will be put in place. Temporary floor tiling will be used in the FOH engineers tent and where necessary (GreatMats, 2010). Environmental Analysis * Surfaces:Grass, dirt paths. Bring your own seating and chairs. Rather informal. * Noise:Present from adjoining road.

Location is away from suburban areas. Noise restrictions apply yet are rarely enforced in this region. * Weather:Dry and sometimes windy. Subject to change. * Rain:Stage will be covered. Audience members not under cover. In case of rain audience participants are advised to bring umbrellas. Rain not common in this region. * Temperature:Temperate climate. If audience participants feel the heat, first aid is near by. System Design Requirements This specific event consists of the following: * An audience of approximately 1500-2000 people. * Drum Kit. * Electric Bass Guitar. Electric Guitar. * Acoustic Guitar. * Keyboard. * 5 Solo Choir Vocalists. * 30 piece children’s Choir. Based on the system power per person rule, 5 watts per audience member is ideal for a low-key event (BS Sound;, 1998). This event however, pertains to a more sonically intense outcome consisting of a choir and a rock band that additionally will be playing in an outdoor scenario. Due to this, the power needed per person increases by over 100% to a fitting 16watts per person. This calculated based on the maximum possible audience attendance number. 2000(people) X 16W = 32,000 Watts” Crown Audio recommends the following: * Rock music in a stadium, arena or amphitheater (100 to 300 feet from speaker to audience): At least 4,000 to 15,000 W * Rock music at a small outdoor festival. At least 1,000 to 3,000 W. (Crown Audio, 2007) Bartman Audio recommends the following: * Contemporary pop/light rock band – minimum of 8 watts per person (4,000 Watts would cover an audience of 500). * Hard rock or metal band – minimum of 12 watts per person (6,000 watts would cover an audience of 500). Audience sizes over 2,000 – “Stadium” system recommended. Stadium system – 28,000 watts – 56,000 watts (Bartman Audio Production, 2006) Keeping in mind that although a rock concert in an arena could be powered by 15,000 watts (allowing only 6 dB of headroom for peaks,) it is often the case that large touring sound companies using 80,000 to 400,000 watts total. This is needed to handle 20-to-24 dB peaks without any clipping relative to the genre at hand (Crown Audio, 2007). Considering this is a choir and a light rock band, that much power will not be needed.

With the above considerations in mind, a total wattage of between 15,000 and 17,000 watts is desirable, as this will provide enough headroom for a quality audio performance along with a suitable volume level for all audience members. Requirement: 15000watts/2000people = 7. 5watts per person In addition, it is also paramount for the audio quality to be consistently audible for all members of the audience. This will be achieved by utilising a system design configuration that focus’ on clarity and direction whilst also rendering itself sympathetic to the sensitive ears of the general public not attending the event.

The System With a desired total power being between 15,000 and 17,000 Watts, the (PA) system consists of the following: * J8 Loudspeaker (D&B Audiotechnik, 2010) * Q1 Loudspeaker (D&B Audiotechnik, 2010) * JSub Subwoofer (D&B Audiotechnik, 2010) The proposed Digital Line Array configuration will be ‘flown’; suspended 6+meters above ground. These DVA’s will be located on both sides of the stage. The 4 JSub Subwoofers will be equally spaced along the length of the stage, 2 Jsubs will sit atop the DVA, 2 will sit on the ground as to maximise the reach of the low frequency content.

Figure 1:Line Array Configuration Figure 1 shows the relative configuration of 16 J8 Loudspeakers and 2 Jsub Units in a Digital Line Array. One can also see that the load support and centre of gravity are configured in a way as to adhere to the load support specifications and safety regulations (63% of BGV-C1 load limit). Finally, the loudspeaker angle are splayed evenly relative to the grounds dimensions, this allows for all audience members to receive and enjoyable, even level of sound whilst also maintain a tight spread that will not exceed the noise level regulations of the events location. Figure 2:Jsub Frequency Map

Figure 2 shows ArrayCalc’s (D&B Audiotechnik, 2010) proposed frequency spread of the 2 Jsub’s evenly spaced on each end of the stage. Unfortunately this doesn’t incorporate the Jsub’s adoring the digital array system (represented by the black squares). If these were implemented in the above calculations, one would assume an even spread of low frequencies across the board. Figure 3:Line Array Analysis Figure 3 displays the acoustic spread of the proposed configuration. From the above data (all figures) we can assume the following: * All audience members are subject to audible sound at a level above 100dB. A relatively even frequency spread. * No misdirected sonic energy. * A listening ‘sweet spot’ at around 50meters. Perfect for the FOH engineer to maintain a quality mix. * Fills (Q1) provide audio for audience member not in the acoustic path of the DVA. * Good low frequency cover. One must remember that despite a peak of 128dB at 15meters in figure 3, this is a ‘peak’ not an average SPL level. It is up to the FOH engineer to provide safe and even mix prior to the event at sound check. Foldback The proposed foldback configuration will comprise of 4 JBL PRX512MIO’s (JBL, 2010).

They will be situated centre stage and both stage right and left. The foldback mixes will be separated into a centre channel as well as the left and right side fills enabling various mixes for various performance focus. These speakers are active and require no separate amp enclosure. Figure 4:Foldback Speaker Placement Mixer/Desk Function wise, the Digidesign Venue (Digidesign, 2010) is a perfect choice for this event. The Venue has 24 input faders, 8 output faders, 16 aux sends and being a digital desk has the option of onboard effects (eq, compressor, etc). Signal Flow

The signal flow diagram is located in the appendix. From this diagram one can assume the following points: * The low frequency content of the mix is sent to a sub mix. This means that all frequencies below 240Hz go to the Jsubs whilst frequencies above 240Hz go to the J8s and Q1s. This will ensure a better output clarity * Similarly, the foldback mix can be controlled according to which area of the performance it’s catering for. Or rather, mix’s can be eq’d separately for the choir, drummer, or band. * Outboards effects sends can be used accordingly. * An amp is present for every pair of speakers.

This allows an adequate power supply and thus an adequate SPL for the audience size. * Both the electric and bass guitar feed directly from their amps. Effects pedals can be implemented if necessary. * Seeing as the field length is only 70meters, a delay stack is not utilized. * The 30-piece choir is mic’d using an XY pair; the solos are also recorded in this manner. Sound Reinforcement Analysis This particular event caters to two stationary acts and thus once the equipment is setup, it requires limited repositioning. This allows for a smooth and faultless playback system. “Rock” Band

Instrument| Microphone/D. I| Leads| Accessories| Electric Bass| SMDI active DI| 1 x 10m MXLR-FXLR1 x 10m Jack2Jack| | Electric Guitar| SMDI active DI| 1 x 10m MXLR-FXLR1 x 10m Jack2Jack| Chorus Pedal| Keyboard| SMDI active DI| 2 x 5m MXLR-FXLR2 x 10m Jack-Jack| | Acoustic Guitar| Rode NT5| 2 x 5m MXLR-FXLR| 1 x Mic Stand| Drum KitKickOverheads | Shure KSM44 (2)Sennheiser e902| 3 x 10m MXLR-FXLR| 3 x Mic Stand| Choir Instrument| Microphone/D. I| Leads| Accessories| Choir (30x)| Nuemann KM183 (2)| 2 x 20m MXLR-FXLR| 2 x Mic Stand| Solo (5x)| Nuemann KM183 (2)| 2 x 20m MXLR-FXLR| 2 x Mic Stand| FOH

Speaker/PA/Drivers| Leads| DVA J8 (16)| 16 x 1m MXLR-FXLR | DVA Q1 (4)| 4 x 6m MXLR-FXLR | DVA Jsubs (4)| 4 x 20m MXLR-FXLR | Amp Type| Leads| D12 Amplifier (2)| 4 x 20m power/ MXLR-FXLR | D6 Amplifier (2)| 2 x 20m power/MXLR-FXLR | D12 Amplifier (1)| 2 x 20m power/MXLR-FXLR | Foldback Location| Speaker/PA/Drivers| Leads| Side fills| JBL PRX512MI (2)| 2 x 20m MXLR-FXLR 2 x 3m MXLR-FXLR | Centre| JBL PRX512MI (2)| 2 x 20m MXLR-FXLR 2 x 3m MXLR-FXLR | Stage Box/Mixer Purpose| Configuration| Leads| Input| 11 inputs| Multicore – 40m Snake and 11 + 4 Stage box| Mixer| From stage box| 11 input leads| | | Overall Equipment List The following list also incorporates ‘spares,’ as it essential to have backup materials incase of unforeseen misfortune. Audio| Inventory| MXLR-FXLR 1m| 20| MXLR-FXLR 3m| 10| MXLR-FXLR 5m| 10| MXLR-FXLR 10m| 20| MXLR-FXLR 20m| 20| |  | Power| Inventory| 240V Extension 5m| 5| 240V Extension 10m| 15| 240V Extension 30m| 5| 240V Extension 50m| 5| | | Misc| Inventory| Gaffer Tape| 4| Cable cover mats 30m| 2| AA/AAA Batteries | 16| Gloves| 8| | | Rigging| Inventory| J Flying Frame| 4| J Hoist Connect Chain| 4| J Safety Chain| 2| | | Speaker/PA| Inventory| JSUB| 4| J8| 16|

Q1| 4| JBL PRX512MI | 2| | | Microphones| Inventory| SMDI active DI| 4| Rode NT5| 1| Shure KSM44 | 2| Sennheiser e902| 1| Nuemann KM183 | 4| | | Amps| Inventory| D12| 3| D6| 1| | | Stage Box| Inventory| Stagebox| 1| | | Stands| Inventory| Tall| 5| Short| 5| Music Stands| 8| Power As there is no power on site at this event, a power generator will be needed. In order to meet the power requirement a Kohler 100kVA 3 Phase 50Hz KD110 generator will be used. In addition to this, a power distributor will also be used to help direct power to where it’s needed. The following diagram displays the flow of power.

Figure 5:Power Distribution Watts Per Person FOH (peak) J8 – 500 x 16 = 8000watts Q1 – 400 x 4 = 1600watts Jsub – 800 x 4 = 3200watts JBL – 500 x 4 = 2000 Total = 14800watts 14800/2000 = 7. 4watts/perperson Conclusion With this particular setup the event is sure to run smoothly. The audio system configuration allows for a clean and audible sound (even frequency dispersion) for all attending. The live engineer is equipped with a setup that allows for easy control of both the FOH and the foldback allowing for the best possible performance for the performers present. Bibliography Bartman Audio Production. 2006). Sound Systems – details & rates. Retrieved April 28, 2010, from Bartman Audio Production: http://www. bartmanaudio. com/concert_sound. html BS Sound;. (1998). Balanced vs Unbalanced, Passive vs Active & a third unrelated topic Why do Valves sound better? Retrieved April 28, 2010, from BS Sound, Technical Advice. : http://www. bssound. com. au/advice/bsadvice. htm Crown Audio. (2007). How Much Amplifier Power Do I Need? . Retrieved April 27, 2010, from Crown Audio: http://www. crownaudio. com/amp_htm/amp_info/how_much_power. htm D&B Audiotechnik. (2010). Array Caculators: ArrayCalc 5.

Retrieved April 30, 2010, from D&B Audiotechnik: http://www. dbaudio. com/en/support/down/array/ D&B Audiotechnik. (2010). The J Series. D&B Audiotechnik. D&B Audiotechnik. (2010). The Q Series. D&B Audiotechnik. Digidesign. (2010). VENUE D-Show. Retrieved 2010, from Digidesign: http://www. avid. com/US/products/VENUE-D-Show/features GreatMats. (2010). Temporary Floor Tile. Retrieved 2010, from GreatMats: http://www. greatmats. com/products/temporary-floor-tile. php JBL. (2010). PRX512MI. Retrieved May 1, 2010, from JBL Professional : http://www. jblpro. com/catalog/general/Product. aspx? PId=284&MId=3 APPENDIX


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